Practice Relating to Rule 101. The Principle of Legality

Geneva Convention III
Article 99, first paragraph, of the 1949 Geneva Convention III provides: “No prisoner of war may be tried or sentenced for an act which is not forbidden by the law of the Detaining Power or by international law, in force at the time the said act was committed.” 
Convention (III) relative to the Treatment of Prisoners of War, Geneva, 12 August 1949, Article 99, first para.
Geneva Convention IV
Article 65 of the 1949 Geneva Convention IV provides: “The penal provisions enacted by the Occupying Power shall not come into force before they have been published … The effect of these penal provisions shall not be retroactive.” 
Convention (IV) relative to the Protection of Civilian Persons in Time of War, Geneva, 12 August 1949, Article 65.
Geneva Convention IV
Article 67 of the 1949 Geneva Convention IV provides: “The courts shall apply only those provisions of law which were applicable prior to the offence.” 
Convention (IV) relative to the Protection of Civilian Persons in Time of War, Geneva, 12 August 1949, Article 67.
European Convention on Human Rights
Article 7(1) of the 1950 European Convention on Human Rights provides:
No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence under national or international law at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time the criminal offence was committed. 
European Convention for the Protection of Human Rights and Fundamental Freedoms, Rome, 4 November 1950, as amended by Protocol No. 11, Strasbourg, 11 May 1994, Article 7(1).
Article 15(2) prohibits derogations from Article 7 of the Convention. 
European Convention for the Protection of Human Rights and Fundamental Freedoms, Rome, 4 November 1950, as amended by Protocol No. 11, Strasbourg, 11 May 1994, Article 15(2).
International Covenant on Civil and Political Rights
Article 15(1) of the 1966 International Covenant on Civil and Political Rights provides:
No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed. If, subsequent to the commission of the offence, provision is made by law for the imposition of the lighter penalty, the offender shall benefit thereby. 
International Covenant on Civil and Political Rights, adopted by the UN General Assembly, Res. 2200 A (XXI), 16 December 1966, Article 15(1).
Article 4 provides that no derogations from Article 15 of the Covenant are possible. 
International Covenant on Civil and Political Rights, adopted by the UN General Assembly, Res. 2200 A (XXI), 16 December 1966, Article 4.
American Convention on Human Rights
Article 9 of the 1969 American Convention on Human Rights provides:
No one shall be convicted of any act or omission that did not constitute a criminal offense, under the applicable law, at the time it was committed. A heavier penalty shall not be imposed than the one that was applicable at the time the criminal offense was committed. If subsequent to the commission of the offense the law provides for the imposition of a lighter punishment, the guilty person shall benefit therefrom. 
American Convention on Human Rights, adopted by the OAS Inter-American Specialized Conference on Human Rights, San José, 22 November 1969, also known as Pact of San José, Article 9.
Article 27 prohibits any suspension of Article 9 of the Convention. 
American Convention on Human Rights, adopted by the OAS Inter-American Specialized Conference on Human Rights, San José, 22 November 1969, also known as Pact of San José, Article 27.
Additional Protocol I
Article 75(4)(c) of the 1977 Additional Protocol I provides:
No one shall be accused or convicted of a criminal offence on account of any act or omission which did not constitute a criminal offence under the national or international law to which he was subject at the time when it was committed; nor shall a heavier penalty be imposed than that which was applicable at the time when the criminal offence was committed; if, after the commission of the offence, provision is made by law for the imposition of a lighter penalty, the offender shall benefit thereby. 
Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I), Geneva, 8 June 1977, Article 75(4)(c). Article 75 was adopted by consensus. CDDH, Official Records, Vol. VI, CDDH/SR.43, 27 May 1977, p. 250.
Additional Protocol II
Article 6(2)(c) of the 1977 Additional Protocol II provides:
No one shall be accused or convicted of a criminal offence on account of any act or omission which did not constitute a criminal offence under the national or international law to which he was subject at the time when it was committed; nor shall a heavier penalty be imposed than that which was applicable at the time when the criminal offence was committed; if, after the commission of the offence, provision is made by law for the imposition of a lighter penalty, the offender shall benefit thereby. 
Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (Protocol II), Geneva, 8 June 1977, Article 6(2)(c). Article 6 was adopted by consensus. CDDH, Official Records, Vol. VII, CDDH/SR.50, 3 June 1977, p. 97.
African Charter on Human and Peoples’ Rights
Article 7(2) of the 1981 African Charter on Human and Peoples’ Rights provides: “No one may be condemned for an act or omission which did not constitute a legally punishable offence at the time it was committed.” 
African Charter on Human and Peoples’ Rights, adopted by the Eighteenth Ordinary Session of the OAU Assembly of Heads of State and Government, Nairobi, 27 June 1981, OAU Doc. CAB/LEG/67/3 rev.5, Article 7(2).
Convention on the Rights of the Child
Article 40(2)(a) of the 1989 Convention on the Rights of the Child provides:
No child shall be alleged as, be accused of, or recognized as having infringed the penal law by reason of acts or omissions that were not prohibited by national or international law at the time they were committed. 
Convention on the Rights of the Child, adopted by the UN General Assembly, Res. 44/25, 20 November 1989, Article 40(2)(a).
ICC Statute
Article 22(1) of the 1998 ICC Statute provides: “A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court.” 
Statute of the International Criminal Court, adopted by the UN Diplomatic Conference of Plenipotentiaries on the Establishment of an International Criminal Court, Rome, 17 July 1998, UN Doc. A/CONF.183/9, Article 22(1).
ICC Statute
Article 24(1)–(2) of the 1998 ICC Statute provides:
No person shall be criminally responsible under this Statute for conduct prior to the entry into force of the Statute … In the event of a change in the law applicable to a given case prior to a final judgement, the law more favourable to the person being investigated, prosecuted or convicted shall apply. 
Statute of the International Criminal Court, adopted by the UN Diplomatic Conference of Plenipotentiaries on the Establishment of an International Criminal Court, Rome, 17 July 1998, UN Doc. A/CONF.183/9, Article 24(1)–(2).
UN-Cambodia Agreement Concerning the Prosecution under Cambodian Law of Crimes Committed During the Period of Democratic Kampuchea
Article 12(2) of the 2003 UN-Cambodia Agreement Concerning the Prosecution under Cambodian Law of Crimes Committed During the Period of Democratic Kampuchea provides:
The Extraordinary Chambers shall exercise their jurisdiction in accordance with international standards of justice, fairness and due process of law, as set out in Articles 14 and 15 of the 1966 International Covenant on Civil and Political Rights, to which Cambodia is a party. 
Agreement between the UN and the Royal Government of Cambodia Concerning the Prosecution under Cambodian Law of Crimes Committed During the Period of Democratic Kampuchea, Phnom Penh, 6 June 2003, Article 12(2).
In accordance with Article 2 of the Agreement, Cambodia’s Law on the Establishment of the ECCC (2001), as amended, further implements these provisions. 
Agreement between the UN and the Royal Government of Cambodia Concerning the Prosecution under Cambodian Law of Crimes Committed During the Period of Democratic Kampuchea, Phnom Penh, 6 June 2003, Article 2.
Universal Declaration of Human Rights
Article 11 of the 1948 Universal Declaration of Human Rights provides:
No one shall be held guilty of any penal offence on account of any act or omission which did not constitute a penal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time the penal offence was committed. 
Universal Declaration of Human Rights, adopted by the UN General Assembly, Res. 217 A (III), 10 December 1948, Article 11.
ILC Draft Code of Crimes against the Peace and Security of Mankind (1991)
Article 10 of the 1991 ILC Draft Code of Crimes against the Peace and Security of Mankind, entitled “Non-retroactivity”, provides:
1. No one shall be convicted under this Code for acts committed before its entry into force.
2. Nothing in this article shall preclude the trial and punishment of anyone for any act which, at the time when it was committed, was criminal in accordance with international law or domestic law applicable in conformity with international law. 
Draft Code of Crimes against the Peace and Security of Mankind, adopted by the International Law Commission, reprinted in Report of the International Law Commission on the work of its forty-third session, 29 April–19 July 1991, UN Doc. A/46/10, 1991, Article 10.
Memorandum of Understanding on the Application of IHL between Croatia and the Socialist Federal Republic of Yugoslavia
Paragraph 4 of the 1991 Memorandum of Understanding on the Application of IHL between Croatia and the Socialist Federal Republic of Yugoslavia requires that all civilians be treated in accordance with Article 75 of the 1977 Additional Protocol I. 
Memorandum of Understanding on the Application of International Humanitarian Law between Croatia and the Socialist Federal Republic of Yugoslavia, Geneva, 27 November 1991, § 4.
Agreement on the Application of IHL between the Parties to the Conflict in Bosnia and Herzegovina
Paragraph 2.3 of the 1992 Agreement on the Application of IHL between the Parties to the Conflict in Bosnia and Herzegovina requires that all civilians be treated in accordance with Article 75 of the 1977 Additional Protocol I. 
Agreement between Representatives of Mr. Alija Izetbegović (President of the Republic of Bosnia and Herzegovina and President of the Party of Democratic Action), Representatives of Mr. Radovan Karadžić (President of the Serbian Democratic Party), and Representative of Mr. Miljenko Brkić (President of the Croatian Democratic Community), Geneva, 22 May 1992, § 2.3.
ILC Draft Code of Crimes against the Peace and Security of Mankind (1996)
Article 13 of the 1996 ILC Draft Code of Crimes against the Peace and Security of Mankind, entitled “Non-retroactivity”, provides:
1. No one shall be convicted under the present Code for acts committed before its entry into force.
2. Nothing in this article precludes the trial of anyone for any act which, at the time when it was committed, was criminal in accordance with international law or national law. 
Draft Code of Crimes against the Peace and Security of Mankind, adopted by the International Law Commission, reprinted in Report of the International Law Commission on the work of its forty-eighth session, 6 May–26 July 1996, UN Doc. A/51/10, 1996, Article 13.
EU Charter of Fundamental Rights
Article 49 of the 2000 EU Charter of Fundamental Rights provides:
No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence under national law or international law at the time when it was committed. 
Charter of Fundamental Rights of the European Union, signed and proclaimed by the European Parliament, the Council and the Commission of the European Union, Nice, 7 December 2000, Article 49.
Argentina
Argentina’s Law of War Manual (1969) provides: “Tribunals will only apply legal provisions existing previously to the offence.” It adds that the “legal provisions decreed by the Occupying Power … cannot have a retroactive effect”. 
Argentina, Leyes de Guerra, RC-46-1, Público, II Edición 1969, Ejército Argentino, Edición original aprobado por el Comandante en Jefe del Ejército, 9 May 1967, §§ 5.025 and 5.026.
Argentina
Argentina’s Law of War Manual (1989) states that the prisoner shall be informed of the offence for which he or she is charged, an offence “which shall constitute a criminal act at the time it was committed”. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 3.30.
The manual further states that criminal provisions “cannot have a retroactive effect” and that the alleged offence against the accused “must constitute a criminal act at the moment it was committed”. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, §§ 5.08 and 5.09 (occupied territory); see also § 4.15 (civilians).
The same provision applies in non-international armed conflicts. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 7.10.
Canada
Canada’s LOAC Manual (1999) provides that no prisoner of war “may be tried or punished for any offence which was not, at the time of its commission, forbidden by International Law or the law of the Detaining Power”. 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 10-7, § 76.
With respect to occupied territories, the manual states: “The penal provisions enacted by the occupant must not be retroactive.” 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 12-6, § 49(a).
The manual further provides: “No person may be tried for a war crime unless the crime in question was an offence at the time of its commission in accordance with national legislation or International Law.” 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 16-6, § 42.
The same provision applies to non-international armed conflicts. 
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 17-3, § 29(c).
Canada
Canada’s LOAC Manual (2001) states in its chapter on the treatment of prisoners of war (PWs): “No PW may be tried or punished for any offence, which was not, at the time of its commission, forbidden by International Law or the law of the Detaining Power.” 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1040.2.
In its chapter on rights and duties of occupying powers, the manual states: “Under [the 1949 Geneva Convention IV] the legislative powers of the occupant in the sphere of criminal law are restricted in the following ways: a. The penal provisions enacted by the occupant must not be retroactive”. 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1229.1.a.
In its chapter on “War crimes, individual criminal liability and command responsibility”, the manual further states: “No person may be tried for a war crime unless the crime in question was an offence at the time of its commission in accordance with national legislation or International Law.” 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1617.5.
In its chapter on non-international armed conflicts, the manual states:
As a minimum, accused persons:
c. shall not be found guilty of an offence in respect of any act or omission which was not an offence at the time of commission, nor shall any punishment be more severe than was applicable at that time, although, if the punishment has been alleviated, the accused shall benefit accordingly. 
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 1716.2.c.
Colombia
Colombia’s Instructors’ Manual (1999) provides: “Nobody can be tried except according to the laws that pre-existed the alleged act.” 
Colombia, Derechos Humanos & Derecho Internacional Humanitario – Manual de Instrucción de la Guía de Conducta para el Soldado e Infante de Marina, Ministerio de Defensa Nacional, Oficina de Derechos Humanos, Fuerzas Militares de Colombia, Santafé de Bogotá, 1999, p. 10.
Mexico
Mexico’s Army and Air Force Manual (2009), in a section on the 1949 Geneva Convention III, states:
Judicial procedure must be regular, that is, it must include at least the following guarantees: the accused must be immediately informed of the particulars of the offence he is alleged to have committed, which must have constituted an offence at the time it was committed. 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, § 191.
In a section on the obligations of the occupying power under the 1949 Geneva Convention IV, the manual states:
B. In order to ensure that justice is observed, the courts can apply only those provisions of law which were applicable prior to the offence, and which are in accordance with general principles of law …
C. Judicial procedure must be regular, that is, it must include at least the following guarantees:
b. the crime with which the accused is charged must have constituted an offence at the time it was committed. 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, § 238(B) and (C)(b).
Netherlands
The Military Manual (1993) of the Netherlands provides with respect to non-international armed conflict: “Nobody may be condemned for acts or omissions which did not constitute a punishable act at the time of the act or omission in question.” 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, p. XI-5.
Netherlands
The Military Manual (2005) of the Netherlands states: “A prisoner of war may not be sentenced for an act which was not punishable at the time when it was committed.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0747.
In its chapter on non-international armed conflict, the manual states that “[n]o derogation is possible from the [prohibition] of … penalties heavier than applicable at the time of the offence”. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1020.
In its chapter on non-international armed conflict, the manual states:
Section 11 - Prosecutions and procedural guarantees
1071. The prosecution and punishment of offences relating to the armed conflict should be subject to the following conditions (this relates to the bearing of arms and the committing of offences and war crimes during the internal armed conflict):
- no one may be convicted of an offence that was not punishable by law at the time it was committed. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1071.
In its chapter on peace operations, the manual states:
Section 2 - Applicability of human rights
1211. Human rights should be respected … However, “in time of war or in case of any other general state of emergency which threatens the existence of the country,” certain human rights may be curtailed as long as the situation strictly necessitates such measures. But the right to life, the prohibition of torture, slavery and forced labour, and the legal principle “no punishment without prior legal provision” cannot be waived. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1211.
New Zealand
New Zealand’s Military Manual (1992) states: “No prisoner may be tried or punished for any offence which was not, at the time of its commission, forbidden by international law or the law of the Detaining Power.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 932(2).
The manual further states: “No one shall be accused or convicted of a criminal offence on account of any act or commission which did not constitute a criminal offence under the national or international law to which he was subject at the time when it was committed.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1137(4)(c).
The manual also states: “The penal provisions enacted by the Occupying Power must not be retroactive.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1327(1)(a).
The manual further states: “No person may be tried for a war crime unless the act in question was an offence at the time of its commission.” 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1711(3).
With respect to non-international armed conflicts, the manuals states:
No one shall be guilty of an offence in respect of any act or omission which was not an offence at the time of commission, nor shall any punishment be more severe than was applicable at that time, although, if the punishment has been alleviated, the accused shall benefit accordingly. 
New Zealand, Interim Law of Armed Conflict Manual, DM 112, New Zealand Defence Force, Headquarters, Directorate of Legal Services, Wellington, November 1992, § 1815(2)(c).
Peru
Peru’s IHL Manual (2004) states that a person charged with a criminal offence under international humanitarian law must be provided with certain guarantees, including: “application of the law in force at the time the offence was committed; the effect of criminal law provisions cannot be retroactive”. 
Peru, Manual de Derecho Internacional Humanitario para las Fuerzas Armadas, Resolución Ministerial Nº 1394-2004-DE/CCFFAA/CDIH-FFAA, Lima, 1 December 2004, § 32.n.(3).
Peru
Peru’s IHL and Human Rights Manual (2010) states that a person charged with a criminal offence under international humanitarian law must be provided with certain guarantees, including: “[a]pplication of the law in force at the time the offence was committed; [the effect of criminal law provisions] cannot be retroactive.” 
Peru, Manual de Derecho Internacional Humanitario y Derechos Humanos para las Fuerzas Armadas, Resolución Ministerial No. 049-2010/DE/VPD, Lima, 21 May 2010, § 33(n)(3), p. 251.
Spain
Spain’s LOAC Manual (1996) provides:
No prisoner shall be subject to judicial proceedings or be sentenced for an act which was not previously prohibited whether by the national legislation of the party under whose power he is, or by International Law in force at the time the act was committed. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, Division de Operaciones, 18 March 1996, Vol. I, § 8.7.c.(1).
Spain
Spain’s LOAC Manual (2007) states: “No prisoner of war may be tried or sentenced for an act which is not forbidden by the law of the detaining power or by international law in force at the time the act was committed.” 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 8.7.c.(1).
Sweden
Sweden’s IHL Manual (1991) considers that the fundamental guarantees for persons in the power of one party to the conflict as contained in Article 75 of the 1977 Additional Protocol I are a part of customary international law. 
Sweden, International Humanitarian Law in Armed Conflict, with reference to the Swedish Total Defence System, Swedish Ministry of Defence, January 1991, Section 2.2.3, p. 19.
United Kingdom of Great Britain and Northern Ireland
The UK Military Manual (1958) provides: “No prisoner of war may be tried or sentenced for an act which is not forbidden by the law of the Detaining Power or by international law in force at the time the act in question was committed.” 
United Kingdom, The Law of War on Land being Part III of the Manual of Military Law, The War Office, HMSO, 1958, § 223.
United Kingdom of Great Britain and Northern Ireland
The UK LOAC Pamphlet (1981) provides that no prisoner of war “may be tried or sentenced for an act which is not forbidden by the law of the Detaining Power or by international law in force when the act in question was committed”. 
United Kingdom, The Law of Armed Conflict, D/DAT/13/35/66, Army Code 71130 (Revised 1981), Ministry of Defence, prepared under the Direction of The Chief of the General Staff, 1981, Section 8, p. 33, § 19(f).
United Kingdom of Great Britain and Northern Ireland
The UK LOAC Manual (2004) states in its chapter on the protection of civilians in the hands of a party to the conflict:
In the case of penal offences relating to the armed conflict, the basic principles of natural justice must be observed … These principles include the following: … no one shall be accused or convicted of a criminal offence on account of any act or omission which did not constitute a criminal offence under the national or international law to which he was subject at the time when it was committed; nor shall a heavier penalty be imposed than that which was applicable at the time when the criminal offence was committed; if, after the commission of the offence, provision is made by law for the imposition of a lighter penalty, the offender shall benefit thereby. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 9.6.
With regard to prisoners of war, the manual provides: “No prisoner of war may be tried or sentenced for an act that was not an offence under either the law of the detaining power or the international law in force at the time of its commission.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 8.130.
In its chapter on occupied territory, the manual states: “New criminal law enacted by the occupying power comes into force only after it has been duly published to the inhabitants in writing in their own language. It must not be retroactive.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 11.58 11 .
With regard to internal armed conflicts in which the 1977 Additional Protocol II is applicable, the manual provides:
no one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under the law, at the time when it was committed; nor shall a heavier penalty be imposed than that which was applicable at the time when the criminal offence was committed; if after the commission of the offence, provision is made by law for the imposition of a lighter penalty, the offender shall benefit thereby. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 15.42.
In its chapter on enforcement of the law of armed conflict, the manual states: “It is a fundamental principle of law that no person may be tried for a war crime unless the act in question was an offence at the time of its commission.” 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.30.
United States of America
The US Field Manual (1956) reproduces Article 99 of the 1949 Geneva Convention III. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, § 175.
With respect to situations of occupation, the manual uses the same wording as Article 65 of the 1949 Geneva Convention IV. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, § 435.
United States of America
The US Air Force Pamphlet (1976) provides that no prisoner of war “may be tried or sentenced for an act which is not forbidden by the law of the detaining power or by international law in force at the time the act was committed”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 13-8.
Venezuela
Venezuela’s Penal Code (2005) states:
Article 1. No one may be punished for an act not expressly penalized in the law, nor be subject to penalties not previously established.
Article 2. Penal laws shall have retroactive effect only if they benefit the accused or convicted person and shall be applicable even after the case is closed with the delivery of a final sentence and the convicted person is already serving a sentence. 
Venezuela, Penal Code, 2005, Articles 1–2.
Note. Many pieces of domestic legislation contain the principle of non-retroactivity in criminal matters. 
See, e.g., India, Constitution, 1950, Article 22; Kenya, Constitution, 1992, Article 77(4); Kuwait, Constitution, 1962, Article 32; Kyrgyzstan, Criminal Code, 1997, Article 7.
These have not been listed here.
Afghanistan
Afghanistan’s Interim Criminal Procedure Code (2004) states: “The Supreme Court amends directly the protested decision when law provisions more favorable to the accused, even if supervened after the filing of the recourse, must be applied.” 
Afghanistan, Interim Criminal Procedure Code, 2004, Article 77(3).
Argentina
Argentina’s Law on the Implementation of the 1998 ICC Statute (2006) states: “No provision establishing criminal offences under the Rome Statute [1998 ICC Statute] or this law shall be applied in violation of the principle of legality”. 
Argentina, Law on the Implementation of the 1998 ICC Statute, 2006, Article 13.
Azerbaijan
Azerbaijan’s Criminal Code (1999), as amended to 2007, states:
The criminality and punishment of a deed (action or inaction) shall be determined by the criminal law that was operative during commitment of this deed (action or inaction). No one shall be applied to criminal liability for a deed which was not admitted as a crime at the time of committing it. 
Azerbaijan, Criminal Code, 1999, as amended to Law 522-11QD dated 25 December 2007, Article 10.1.
Bangladesh
Bangladesh’s International Crimes (Tribunal) Act (1973) states that the “violation of any humanitarian rules applicable in armed conflicts laid down in the Geneva Conventions of 1949” is a crime. 
Bangladesh, International Crimes (Tribunal) Act, 1973, Section 3(2)(e).
Bosnia and Herzegovina
Bosnia and Herzegovina’s Criminal Code (2003) states in its Article 3: “No punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, has not been defined as a criminal offence by law or international law, and for which a punishment has not been prescribed by law.” 
Bosnia and Herzegovina, Criminal Code, 2003, Article 3(2).
The Criminal Code, as amended in 2004, states: “Article 3 … of this Code shall not prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of international law.” 
Bosnia and Herzegovina, Criminal Code, 2003, as amended in 2004, Article 4a.
Burundi
Burundi’s Penal Code (2009), which includes a chapter on war crimes, states:
No offence can be punished by penalties which were not provided for by law before the offence was committed.
However, in the case of concurrence of two criminal laws, a former [law] which was in force when the offence was committed, and another [law] which was enacted since the [commission of the] offence and before a final judgement has been rendered, the new law shall only be applied if it imposes a less severe penalty. 
Burundi, Penal Code, 2009, Article 4.
Cambodia
Cambodia’s Law on the Establishment of the ECCC (2001), as amended in 2004, provides in its chapter on the proceedings of the Extraordinary Chambers:
The Extraordinary Chambers of the … court shall exercise their jurisdiction in accordance with international standards of justice, fairness and due process of law, as set out in Articles 14 and 15 of the 1966 International Covenant on Civil and Political Rights. 
Cambodia, Law on the Establishment of the ECCC, 2001, as amended in 2004, Article 33 new.
Central African Republic
The Central African Republic’s Penal Code (2010), which contains a chapter on war crimes, states in its general provisions: “Crimes, offences or infractions not forbidden by the law at the time the said act was committed may not be punished.” 
Central African Republic, Penal Code, 2010, Article 2.
China
China’s Criminal Law (1979), as amended in 1997, states:
Article 3 For acts that are explicitly defined as criminal acts in law, the offenders shall be convicted and punished in accordance with law; otherwise, they shall not be convicted or punished.
Article 9 This Law shall be applicable to crimes which are stipulated in international treaties concluded or acceded to by the People’s Republic of China and over which the People’s Republic of China exercises criminal jurisdiction within the scope of obligations, prescribed in these treaties, it agrees to perform.
Article 12 If an act committed after the founding of the People’s Republic of China and before the entry into force of this Law was not deemed a crime under the laws at the time, those laws shall apply. If the act was deemed a crime under the laws in force at the time and is subject to prosecution under the provisions of Section 8, Chapter IV [which deals with limitation periods] of the General Provisions of this Law, criminal responsibility shall be investigated in accordance with those laws. However, if according to this Law the act is not deemed a crime or is subject to a lighter punishment, this Law shall apply.
Before the entry into force of this Law, any judgment that has been made and has become effective according to the laws at the time shall remain valid. 
China, Criminal Law, 1979, as amended in 1997, Articles 3, 9 and 12.
Colombia
Colombia’s Law on the Disciplinary Regime of the Armed Forces (2003) states: “The addressees of the present rules may only be investigated and disciplinarily sanctioned for acts which constituted an offence according to the law in force at the time when the acts took place.” 
Colombia, Law on the Disciplinary Regime of the Armed Forces, 2003, Article 3.
Colombia
Colombia’s Criminal Procedure Code (2004) states: “Nobody may be subjected to an investigation or convicted except in accordance with the procedural law in force at the time of the acts”. 
Colombia, Criminal Procedure Code, 2004, Article 6.
Croatia
Croatia’s Criminal Code (1997), as amended to 2006, states:
No one shall be punished, and no criminal sanction shall be applied, for conduct which did not constitute a criminal offence under a statute or international law at the time it was committed and for which the type and range of punishment by which the perpetrator can be punished has not been prescribed by statute. 
Croatia, Criminal Code, 1997, as amended to 2006, Article 2.
Democratic Republic of the Congo
The Democratic Republic of the Congo’s Military Penal Code (2002) provides:
Article 2
No offence can be punished with a penalty not provided for by law before the offence was committed. However, new provisions less severe than those of the old law apply to offences that were committed before the new provisions entered into force and that have not yet led to a final conviction.
However, the application of the new law has no effect on the validity of proceedings completed in accordance with the old law. The penalty nevertheless is no longer executed if it was pronounced for a fact which, according to a law subsequent to the judgement, no longer has the character of an offence. 
Democratic Republic of the Congo, Military Penal Code, 2002, Article 2.
Denmark
Denmark’s Military Criminal Code (1973), as amended in 1978, provides:
Any person who uses war instruments or procedures the application of which violates an international agreement entered into by Denmark or the general rules of international law, shall be liable to the same penalty [i.e. a fine, lenient imprisonment or up to 12 years’ imprisonment]. 
Denmark, Military Criminal Code, 1973, as amended in 1978, § 25(1).
Denmark’s Military Criminal Code (2005) provides:
Any person who deliberately uses war means [“krigsmiddel”] or procedures the application of which violates an international agreement entered into by Denmark or international customary law, shall be liable to the same penalty [i.e. imprisonment up to life imprisonment]. 
Denmark, Military Criminal Code, 2005, § 36(2).
El Salvador
El Salvador’s Penal Code (1997), as amended to 2008, which contains a section on violations of the laws or customs of war, states in its general provisions:
No one may be punished for an act or omission that was not defined by criminal law, in a precise and clear manner, as an offence or a fault, nor can a person be punished or made the object of a security measure if the law was not in force prior [to when the offence was committed]. 
El Salvador, Penal Code, 1997, as amended to 2008, Article 1.
In its concluding general section, the Penal Code further states: “All persons accused of offences or faults, at the time this Code enters into force, will benefit from the application of the more favourable provisions contained either in this law or in the derogated one.” 
El Salvador, Penal Code, 1997, as amended in 2008, Article 407.
Ethiopia
Ethiopia’s Criminal Code (2004) states:
Article 2.- Principle of Legality.
(2) The Court may not treat as a crime and punish any act or omission which is not prohibited by law.
The Court may not impose penalties or measures other than those prescribed by law.
(3) The Court may not create crimes by analogy.
(4) The above provisions shall not prevent the Court from interpreting the law. In cases of doubt the Court shall interpret the law according to its spirit, in accordance with the meaning intended by the legislature so as to achieve the purpose it has in view.
Article 5.- Non-retrospective Effect of Criminal Law.
(1) If an act, declared to be a crime both under the repealed legislation and this Code was committed prior to the coming into force of this Code, it shall be tried in accordance with the repealed law.
(2) An act declared to be a crime under this Code but not under the repealed law and committed prior to the coming into force of this Code is not punishable.
(3) No act shall be tried or punished where it was a crime committed under the repealed legislation but is not declared so to be under this Code. If proceedings have been instituted they shall be discontinued.
Article 6.- Exception: Application of the More Favourable Law.
Where the criminal is tried for an earlier crime after the coming into force of this Code, its provisions shall apply if they are more favourable to him than those in force at the time of the commission of the crime.
The Court shall decide in each case whether, having regard to all the relevant provisions, the new law is in fact more favourable.
Article 9.- Enforcement of Judgments passed under Repealed Legislation.
Where a sentence has been passed in accordance with the repealed legislation its enforcement shall be governed by the following principles:
(1) If the Code no longer restrains the act in respect of which the sentence was passed the punishment shall no longer be enforceable or shall forthwith cease to have effect.
(2) Where a sentence has been passed for the breach of a criminal law enacting a prohibition or an obligation limited to a given period of time for special reasons of a transitory nature, the expiration of the said period shall not bar the enforcement of the punishment, nor shall the prosecution be barred by such expiration.
Article 15.- Crimes Committed in a Foreign Country by a Member of the Defence Forces.
(2) In cases of crimes against international law and specifically military crimes as defined in Article 269–322, the member of the Defence Forces shall remain subject to national law and be tried under the provisions of this Code by Ethiopian military courts. 
Ethiopia, Criminal Code, 2004, Articles 2(2)–(4), 5, 9(1)–(2) and 15(2).
Georgia
Georgia’s Law on Occupied Territories (2008) states:
The application of the provisions of Articles 5 and 8 of this Law [regarding, respectively, right to property in occupied territories and unauthorized officials] shall be extended to relations formed since 1990. No retroactive force shall be applied to any provision of the Articles entailing criminal responsibility. 
Georgia, Law on Occupied Territories, 2008, Article 11(2).
Guatemala
Guatemala’s Law on the Protection of Childhood and Adolescence (2003) states: “Principle of legality. No adolescent may be prosecuted for acts which do not violate criminal law. He or she may not be prosecuted nor subjected to [disciplinary] measures or [penal] sanctions which were not previously established by law.” 
Guatemala, Law on the Protection of Childhood and Adolescence, 2003, Article 145.
Islamic Republic of Iran
The Islamic Republic of Iran’s Islamic Penal Code (1982) states:
No punishment shall be awarded for the commission or omission of an act in accordance with a law passed subsequent to the act. In case, however, a law is framed subsequent to the commission of an offence which involves mitigation or abolition of the punishment or is favourable to the offender, it shall be applicable to the offences which were committed before the law was framed and in whose case no final judgement has been issued by the court. 
Islamic Republic of Iran, Islamic Penal Code, 1982, Section 6.
Ireland
Ireland’s Geneva Conventions Act (1962), as amended in 1998, provides that any “minor breach” of the 1949 Geneva Conventions, including violations of Article 99 of the Geneva Convention III and Articles 65 and 67 of the Geneva Convention IV, and of the 1977 Additional Protocol I, including violations of Article 75(4)(c), as well as any “contravention” of the 1977 Additional Protocol II, including violations of Article 6(2)(c), are punishable offences. 
Ireland, Geneva Conventions Act, 1962, as amended in 1998, Section 4(1) and (4).
Japan
Japan’s Code of Criminal Procedure (1948), as amended in 2006, states:
The court shall, on a ruling, render a dismissal of prosecution when:
(ii) The facts written in the charging sheet, although they may be true, do not include any facts constituting a crime. 
Japan, Code of Criminal Procedure, 1948, as amended in 2006, Article 339(1)(ii).
Morocco
Morocco’s Penal Code (1962) provides:
Article 3
No one can be convicted for an act which is not expressly provided for as an offence by the law, nor punished by penalties the law has not laid down.
Article 4
No one can be convicted for an act which, according to the law in force at the time it was committed, did not constitute an offence.
Article 5
No one can be convicted for an act which, by effect of a law subsequent to its commission, no longer constitutes an offence; if a conviction has been pronounced, the execution of main as well as ancillary penalties is ended.
Article 6
If several laws have been in force since the moment the offence was committed and the final judgement, the law whose provisions are the least severe must be applied. 
Morocco, Penal Code, 1962, Articles 3–6.
Morocco
Morocco’s Constitution (1996) provides: “The law shall be the supreme expression of the will of the Nation. All shall abide by it. The law shall have no retroactive effect.” 
Morocco, Constitution, 1996, Article 4.
Norway
Norway’s Military Penal Code (1902), as amended in 1981, provides:
Anyone who contravenes or is accessory to the contravention of provisions relating to the protection of persons or property laid down in … the Geneva Conventions of 12 August 1949 … [and in] the two additional protocols to these Conventions …is liable to imprisonment. 
Norway, Military Penal Code, 1902, as amended in 1981, § 108.
Pakistan
Pakistan’s Anti-Terrorism Act (1997) states:
Punishment for terrorist act committed before this Act
Where a person has committed an offence before the commencement of this Act which if committed after the date on which this Act comes into force would constitute a terrorist act there under he shall be tried under this Act but shall be liable to punishment as authorized by law at the time the offence was committed. 
Pakistan, Anti-Terrorism Act, 1997, Section 38.
Peru
Peru’s Code of Military and Police Justice (2006) states:
Nobody may be convicted without a trial based on law that predates the act for which the person is prosecuted. The trial must fully respect the rights and guarantees established in the Political Constitution [of Peru], in international treaties for the protection of human rights and the norms in the present Code. 
Peru, Code of Military and Police Justice, 2006, Article 150.
Peru
Peru’s Military and Police Criminal Code (2010), which includes provisions on crimes under international humanitarian law, states in the Preliminary Title:
No member of the military or the police may be investigated, judged or punished for an act or omission which was not expressly and unequivocally established as a crime committed in the line of duty by the criminal law in force at the time of its commission. 
Peru, Military and Police Criminal Code, 2010, Article IV.
Philippines
The Philippines’ Executive Order No. 292 (1987) states: “Laws shall have prospective effect unless the contrary is expressly provided.” 
Philippines, Executive Order No. 292, 1987, Book I, Chapter 5, Section 19.
Poland
Poland’s Constitution (1997) states: “Only a person who has committed an act prohibited by a statute in force at the moment of commission thereof, and which is subject to a penalty, shall be held criminally responsible.” 
Poland, Constitution, 1997, Article 42(1).
Poland
Poland’s Penal Code (1997) states: “Criminal liability shall be incurred only by a person who commits an act prohibited under penalty, by a law in force at the time of its commission.” 
Poland, Penal Code, 1997, Article 1(1).
Rwanda
Rwanda’s Constitution (2003) provides:
A state of emergency and a state of siege shall be governed by the law and declared by the President of the Republic, following a decision of the Cabinet.
A declaration of a state of siege or of a state of emergency shall not under any circumstances violate the right to life and physical integrity of the person, the rights accorded to people by law in relation to their status, capacity and nationality; the principle of non-retroactivity of criminal law; the right to legal defence; and freedom of conscience and religion. 
Rwanda, Constitution, 2003, Article 137.
Senegal
Senegal’s Penal Code (1965), as amended in 1999, states: “No felony, misdemeanour or infraction shall be liable to penalties that were not set forth in legislation or regulations prior to their commission.” 
Senegal, Penal Code, 1965, as amended in 1999, Article 4.
Senegal
Senegal’s Penal Code (1965), as amended in 2007, states:
Notwithstanding the provisions in Article 4 [on the principle of legality] of this Code, any individual may be tried or sentenced for acts or omissions referred to in this Chapter [on crimes under international law, including war crimes] and in Article 295.1 [on torture] of the Penal Code which, at the time and place of its commission, constituted a criminal offence according to the general principles of law recognized by the community of nations, regardless of whether or not they constituted a transgression of the law in force at that time and place. 
Senegal, Penal Code, 1965, as amended in 2007, Article 431-6.
Senegal
Senegal’s Constitution (2001), as amended in 2008, states:
No one may be convicted other than by virtue of a law which entered into force before the act was committed.
However, the provisions of the preceding paragraph shall not hinder the prosecution, trial and conviction of any person for acts or omissions which, at the time when they were committed, were defined as criminal under the rules of international law concerning acts of genocide, crimes against humanity and war crimes. 
Senegal, Constitution, 2001, as amended in 2008, Article 9(2)–(3).
Serbia
Serbia’s Criminal Code (2005) states:
No one may be punished, or other criminal sanction imposed, for an offence that did not constitute a criminal offence at the time it was committed, nor may punishment or other criminal sanction be imposed that was not applicable at the time the criminal offence was committed. 
Serbia, Criminal Code, 2005, Article 1.
Sierra Leone
Sierra Leone’s Constitution (1991) states:
23. Provision to secure protection of law.
(7) No person shall be held to be guilty of a criminal offence on account of any act or omission which did not, at the time it took place, constitute such an offence.
(8) No penalty shall be imposed for any criminal offence which is severer in degree or description than the maximum penalty which might have been imposed for that offence at the time when it was committed.
(10) Nothing contained in or done under the authority of any law shall be held to be inconsistent with or in contravention of any provisions of this section … to the extent that the law in question authorises the taking during a period of public emergency of measures that are reasonably justifiable for the purpose of dealing with the situation that exists before or during that period of public emergency.
29. Public emergency.
(2) The President may issue a Proclamation of a state of public emergency only when –
a. Sierra Leone is at war; [or]
b. Sierra Leone is in imminent danger of invasion or involvement in a state of war; or
c. there is actual breakdown of public order and public safety in the whole of Sierra Leone or any part thereof to such an extent as to require extraordinary measures to restore peace and security; or
d. there is a clear and present danger of an actual breakdown of public order and public safety in the whole of Sierra Leone or any part thereof requiring extraordinary measures to avert the same; or
e. there is an occurrence of imminent danger, or the occurrence of any disaster or natural calamity affecting the community or a section of the community in Sierra Leone; or
f. there is any other public danger which clearly constitutes a threat to the existence of Sierra Leone.
(5) During a period of public emergency, the President may make such regulations and take such measures as appear to him to be necessary or expedient for the purpose of maintaining and securing peace, order and good government in Sierra Leone or any part thereof. 
Sierra Leone, Constitution, 1991, Sections 23(7)–(8) and (10) and 29(2) and (5).
Spain
Spain’s Penal Code (1995), as amended in 2010, which includes a chapter on offences against protected persons and objects in the event of armed conflict, states:
The offences and faults committed up until the day of the entry into force of this Law will be judged according to the criminal legislation in force at the time of their commission. However, this Law will be applicable once it enters into force, as long as its provisions are more favorable to the prisoner, even if the facts occurred prior to its entry into force. 
Spain, Penal Code, 1995, as amended on 23 June 2010, Disposición transitoria primera (1), p. 54878.
Switzerland
Switzerland’s Military Criminal Code (1927), taking into account amendments entered into force up to 2011, which also contains a chapter on war crimes, states in a part on general provisions: “A sentence or measure must only be pronounced for an act expressly declared to be an offence by the law.” 
Switzerland, Military Criminal Code, 1927, taking into account amendments entered into force up to 2011, Article 1.
Switzerland
Switzerland’s Penal Code (1937), taking into account amendments entered into force up to 2011, which also contains a chapter on war crimes, states in the book on general provisions: “A sentence or measure must only be pronounced for an act expressly declared to be an offence by the law.” 
Switzerland, Penal Code, 1937, taking into account amendments entered into force up to 2011, Article 1.
Venezuela
Venezuela’s Law on the State of Emergency (2001), which includes situations of internal and international armed conflict, states:
In accordance with Articles 339 of the Constitution of the Bolivarian Republic of Venezuela, Article 4(2) of the [1966] International Covenant on Civil and Political Rights and Article 27(2) of the [1969] American Convention on Human Rights, the guarantee to the [following] rights must not be restricted:
10. The [principle of] legality and the non-retroactivity of laws, in particular of criminal laws. 
Venezuela, Law on the State of Emergency, 2001, Article 7(10).
Venezuela
Venezuela’s Law on the Protection of Children and Adolescents (2007) states: “An adolescent may not be prosecuted or sanctioned for an act or omission which, at the time of its occurrence, was not previously defined in criminal law in an express and unequivocal way as a crime or misdemeanour.” 
Venezuela, Law on the Protection of Children and Adolescents, 2007, Article 253.
Zimbabwe
Zimbabwe’s Constitution (1979), as amended to 2009, states:
THE DECLARATION OF RIGHTS
18 Provisions to secure protection of law
(5) No person shall be held to be guilty of a criminal offence on account of any act or omission that did not, at the time it took place, constitute such an offence, and no penalty shall be imposed for any criminal offence that is severer in degree or description than the maximum penalty that might have been imposed for that offence at the time when it was committed.
26 Interpretation and other savings
(7) No measures taken in relation to a person who is a member of a disciplined force of a country with which Zimbabwe is at war or with which a state of hostilities exists and no law, to the extent that it authorises the taking of such measures, shall be held to be in contravention of the Declaration of Rights. 
Zimbabwe, Constitution, 1979, as amended to 2009, Sections 18(5) and 26(7).
Zimbabwe
Zimbabwe’s Constitution (2013) states:
Chapter 4 – Declaration of Rights
69. Right to a fair hearing
(1) Every person accused of an offence has the right to a fair and public trial within a reasonable time before an independent and impartial court.
70. Rights of accused persons
(1) Any person accused of an offence has the following rights –
(k) not to be convicted for an act or omission that was not an offence when it took place;
(l) not to be convicted for an act or omission that is no longer an offence;
(n) to be sentenced to the lesser of the prescribed punishments if the prescribed punishment for the offence has been changed between the time the offence was committed and the time of sentencing.
86. Limitation of rights and freedoms
(2) The fundamental rights and freedoms set out in this Chapter may be limited only in terms of a law of general application and to the extent that the limitation is fair, reasonable, necessary and justifiable in a democratic society based on openness, justice, human dignity, equality and freedom, taking into account all relevant factors, including –
(b) the purpose of the limitation, in particular whether it is necessary in the interests of defence, public safety, public order, public morality, public health, regional or town planning or the general public interest;
(3) No law may limit the following rights enshrined in this Chapter, and no person may violate them –
(e) the right to a fair trial;
87. Limitations during public emergency
(1) In addition to the limitations permitted by section 86, the fundamental rights and freedoms set out in this Chapter may be further limited by a written law providing for measures to deal with situations arising during a period of public emergency, but only to the extent permitted by this section and the Second Schedule.
(4) No law that provides for a declaration of a state of emergency, and no legislative or other measure taken in consequence of such a declaration may –
(a) indemnify, or permit or authorise an indemnity for, the State or any institution or agency of the government at any level, or any other person, in respect of any unlawful act; or
(b) limit any of the rights referred to in section 86(3), or authorise or permit any of those rights to be violated. 
Zimbabwe, Constitution, 2013, Sections 69(1), 70(1)(k)–(l) and (n), 86(2)(b) and (3)(e), and 87(1) and (4).
Australia
In the Polyukhovich case before Australia’s High Court in 1991, in which the accused was charged with crimes committed during the Second World War, Judge Brennan considered the matter of retrospective criminal laws in international law:
[I]international law not only refuses to countenance retrospective provisions in international criminal law; it condemns as offensive to human rights retrospective municipal criminal law imposing a punishment for [a] crime unless the crime was a crime under international law at the time when the relevant act was done. 
Australia, High Court, Polyukhovich case, Legal Reasoning of Judge Brennan, 14 August 1991, § 37.
Bosnia and Herzegovina
In 2006, in the Maktouf case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
[T]he principle of mandatory application of more lenient law is excluded in processing of those criminal offenses for which at the time of their perpetration it was predictable and generally known that they were contrary to general rules of international law. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Maktouf case, Judgment, 4 April 2006, p. 18.
The Court also stated:
This exception from application of more lenient law is fully justified if one takes into consideration the general purpose of criminal sanctions referred to in Article 6 of the Criminal Code of Bosnia and Herzegovina, since it is obvious that the maximum punishment of 20 years of imprisonment stipulated by the adopted CC [Criminal Code] (after abolition of capital punishment) could not achieve the general purpose of punishment given the gravity of these criminal offenses and their consequences, in particular if we consider the cases referred by the ICTY to the Court of Bosnia and Herzegovina. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Maktouf case, Judgment, 4 April 2006, p. 17.
Bosnia and Herzegovina
In 2006, in the Paunović case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
Crimes Against Humanity thus constitute an imperative principle of international law or rather jus cogens, and it is beyond dispute that in 1992 crimes against humanity were an integral part of international customary law.
… [A]pplication of the 2003 BiH CC [Criminal Code of Bosnia and Herzegovina] [for this offence] is based on the provisions of Article 4(a) [of that Code] which refers to “general principles of international law” in which it was stipulated that Articles 3 and 4 shall not prejudice the trial and punishment of any person for any act or omission which, at the time it was committed, was a criminal offence according to general principles of international law. … [T]hese articles do not challenge trial and punishment of some persons for every act or omission to act which includes the criminal offence of Crimes Against Humanity and which, as such, was not stipulated by the criminal code applicable at the time of commission of the criminal offence. … [the offence of] Crimes Against Humanity represents the criminal offence according to general principles of international law. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Paunović case, Judgment, 27 October 2006, p. 8.
Bosnia and Herzegovina
In 2006, in the Samardžija case, the Panel of the Court of Bosnia and Herzegovina stated:
As regards the applicable substantive law, the Accused objected to the application of the CC BiH [Criminal Code of Bosnia and Herzegovina] (in force as of 1 March 2003 ), pointing out that the Criminal Code of the SFRY [Socialist Federal Republic of Yugoslavia], which was applicable at the time of the events concerned, should be applied. The Accused submitted a letter stating he considered the application of the CC BiH to be a violation of Article 7 of the [European Convention on Human Rights], since, among others, the Criminal Code of the SFRY was more lenient.
In Article 7(1) of the [European Convention on Human Rights] the principle of legality is laid down. This provision of the [European Convention on Human Rights] furthermore contains the general principle prohibiting imposing a heavier penalty than the one that was applicable at the time when the criminal offence was committed. Under Article II(2) of the Constitution of Bosnia and Herzegovina, the [European Convention on Human Rights] has priority over all other laws in [Bosnia and Herzegovina]. These principles have also been laid down in the CC BiH.
First, Article 3 of the CC BiH stipulates the principle of legality; that is, that criminal offences and criminal sanctions shall be prescribed only by law and that no punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, has not been defined as a criminal offence by law or international law, and for which a punishment has not been prescribed by law. Furthermore, Article 4 of the CC BiH stipulates that the law that was in effect at the time when the criminal offence was perpetrated shall apply to the perpetrator of the criminal offence; if the law has been amended on one or more occasions after the criminal offence was perpetrated, the law that is more lenient to the perpetrator shall be applied.
While considering the objection raised by the Accused, it has to be noted that in the Criminal Code of the SFRY, which was applicable in the period relevant to this case, no provision explicitly dealt with crime against humanity as provided for in the Criminal Code of [Bosnia and Herzegovina]. However, taking into consideration other provisions of the valid substantive law, as well as the general principles of international law, this objection of the Defence could not be accepted as well-founded.
Article 4(a) of the CC BiH reads that Articles 3 and 4 of the CC BiH shall not prejudice the trial and punishment of any person for any act or omission, which at the time when it was committed, “was criminal according to the general principles of international law.” Also Article 7(2) of the [European Convention on Human Rights] gives the same exemption, providing that “the same Article shall not prejudice the trial and punishment of any person of any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by civilized nations”.
This provides the possibility to depart, under the described circumstances, from the principles laid down in Articles 3 and 4 of the CC of BiH (and Article 7(1) of the [European Convention on Human Rights]) and thus to depart from a mandatory application of the criminal code applicable at the time of commission and of a more lenient law in proceedings for offences constituting criminal offences under international law. This applies to the proceedings against the Accused, for it concerns an incrimination that involves violation of the rules of international law.
The Court points out that the crimes for which the Accused has been found guilty constituted crimes under international criminal law and thus fall under “the general principles of international law” as stipulated in Article 4(a) of the Law on Amendments to the CC of BiH and thus the CC BiH can be applied in this case on the basis of this provision.
The status that Crimes against Humanity and the attribution of individual criminal responsibility in the period relevant to the Indictment have in international customary law is, among others, in the Report of the Secretary General of the United Nations pursuant to Paragraph 2 of the Security Council Resolution 108, dated 3 May 1993, International Law Commission, Comments on the Draft Code of Crimes against the Peace and Security of Mankind (1996) and jurisprudence of the ICTY and the ICTR.
Finally, the application of the CC BiH is additionally justified by the fact that the imposed sentence is in any event more lenient than the death penalty that was applicable at the time of perpetration of the offence, thereby satisfying the principle of time constraints regarding applicability of the criminal code, i.e. application of a law that is more lenient to the perpetrator. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Samardžija case, Judgment, 3 November 2006, pp. 37–38.
Bosnia and Herzegovina
In 2006, in the Samardžić case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
With regard to the application of the substantive law in this criminal case, the Court finds relevant two legal principles: the Principle of Legality, according to which no punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, has not been defined as a criminal offence by law or international law, and for which a punishment has not been prescribed by law (Article 3 of the CC of BiH) [Criminal Code of Bosnia and Herzegovina] and the principle of Time Constraints Regarding Applicability, according to which the law that was in effect at the time when the criminal offence was perpetrated shall apply to the perpetrator of the criminal offence and if the law has been amended on one or more occasions after the criminal offence was perpetrated, the law that is more lenient to the perpetrator shall be applied (Article 4 of the CC of BiH). 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Samardžić case, Judgment, 13 December 2006, pp. 20–21.
The Court also stated:
Accordingly, the criminal offence of crimes against humanity can in any case be subsumed under “general principles of international law” referred to in Article 4(a) of the CC of BiH. Therefore, regardless of whether viewed from the viewpoint of international customary law or the viewpoint of “principles of international law”, it is indisputable that crimes against humanity constituted a criminal offence in the incriminated period, and that the principle of legality has been met. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Samardžić case, Judgment, 13 December 2006, p. 23.
Bosnia and Herzegovina
In 2007, in the Stanković case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
It is also indisputable that, pursuant to the principle of legality, no punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, has not been defined as a criminal offence by law or international law, and for which no punishment was prescribed by the law (Article 3 of the BiH CC) [Criminal Code of Bosnia and Herzegovina], while, pursuant to the principle of time constraints regarding applicability, the law that was in effect at the time when the criminal offence was perpetrated shall apply to the perpetrator of the criminal offence and if the law has been amended on one or more occasions after the criminal offence was perpetrated, the law that is more lenient to the perpetrator shall be applied (Article 4 of the BiH CC). The principle of legality is also stipulated under Article 7 (2) of the ECHR [European Convention on Human Rights] and Article 15 (1) of the International Covenant on Civil and Political Rights (hereinafter: the ICCPR).
However, Articles (4a) of the BiH CC, which the first instance Verdict correctly refers to, regulates that Articles 3 and 4 of the Code shall not prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of international law. Thus, the provisions of Article 7 (2) of the ECHR and Article 15 (2) of the ICCPR have practically been adopted, therefore providing for departure from the mandatory application of a more lenient law in proceedings conducted for acts which are criminal according to international law. It is stated that this is the case in the proceedings against the accused because this is exactly an incrimination which includes a violation of international law. In other words, as correctly reasoned in the contested Verdict, in the period relevant to the Indictment, Crimes Against Humanity indisputably constituted a criminal offense both from the aspect of international customary law and from the aspect of the general principles of international law. The detailed and comprehensive arguments corroborating such conclusion presented by the first instance panel are absolutely valid and correct, and therefore also accepted by this Panel as a whole.
Further, international customary law and international treaties signed by the Socialist Federative Republic of Yugoslavia automatically became binding on Bosnia and Herzegovina, either during the time when it was part of the Socialist Federative Republic of Yugoslavia or after it became a successor to the former Socialist Federative Republic of Yugoslavia. The 1978 Vienna Convention on Succession of States in respect to Treaties, ratified by the Socialist Federative Republic of Yugoslavia on 18 April 1980, in Article 34 stipulates that a treaty in force at the date of the succession of States in respect of the entire territory of the predecessor State continues to be in force in respect of each successor State so formed unless the States concerned agree otherwise. In addition to the above mentioned, on 10 June 1994, Bosnia and Herzegovina declared that it recognized all the international treaties which were binding on the former Yugoslavia. Article 210 of the Constitution of the Socialist Federative Republic of Yugoslavia, indeed, stipulates that international treaties are automatically implemented and applied from the day of entry into force without the adoption of implementing regulations.
The foregoing results in the correct position of the first instance panel that Bosnia and Herzegovina, as a successor to the former Yugoslavia, ratified the ECHR and the ICCPR, therefore, these treaties are binding on it. Given that they regulate the obligation to try and punish any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of international law, which is definitely the case with Crimes Against Humanity pursuant to the above mentioned, it is indisputable that the arguments of the appeal claiming the opposite are entirely ungrounded and as such refused. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Stanković case, Judgment, 28 March 2007, pp. 13–14.
Bosnia and Herzegovina
In 2007, in the Damjanović case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
Crimes Against Humanity thus constitute an imperative principle of international law and it is indisputable that in 1992 crimes against humanity was an integral part of international customary law.
To wit, the application of the 2003 CC of BiH [Criminal Code of Bosnia and Herzegovina] to the specific criminal offence is grounded on the provision of Article 4 (a) of the [Criminal Code], which again refers to the “general principles of international law” … and it prescribes that Articles 3 and 4 of the said Code do not prevent trial or sanctioning of any person for an act or omission to act, which at the time of the act constituted a criminal offence per general principles of international law. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Damjanović case, Judgment, 13 June 2007, p. 13.
Bosnia and Herzegovina
In 2007, in the Kovačević case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
[I]t is beyond dispute that according to the principle of legality, no punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, had not been defined as a criminal offense by law or international law, and for which a punishment had not been prescribed by law … , whereas the principle of time constraints regarding applicability provides that the law that was in effect at the time when the criminal offense was perpetrated shall apply to the perpetrator of the criminal offense; if the law has been amended on one or more occasions after the criminal offense was perpetrated, the law that is more lenient to the perpetrator shall be applied. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Kovačević case, Judgment, 22 June 2007, p. 7.
The Court also stated that the provisions of the Criminal Code enshrining the principle of legality “shall not prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of International law”. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Kovačević case, Judgment, 22 June 2007, p. 7.
Bosnia and Herzegovina
In 2007, in the Šimšić case, the Appellate Panel of the Court of Bosnia and Herzegovina stated:
[T]he Court finds relevant two legal principles: the principle of legality, according to which no punishment or other criminal sanction may be imposed on any person for an act which, prior to being perpetrated, has not been defined as a criminal offence by [domestic] law or international law, and for which a punishment has not been prescribed by law (Article 3 of the CC of BiH [Criminal Code of Bosnia and Herzegovina]) and the principle of time constraints regarding applicability, according to which the law that was in effect at the time when the criminal offence was perpetrated shall apply to the perpetrator of the criminal offence and if the law has been amended on one or more occasions after the criminal offence was perpetrated, the law that is more lenient to the perpetrator shall be applied (Article 4 of the CC of BiH).
[Article 7(1) of the European Convention on Human Rights and Article 15(1) of the International Covenant on Civil and Political Rights] prescribe the prohibition of imposing a heavier penalty, but they do not stipulate the mandatory application of the most/more lenient law (if the law was amended on several occasions) to the perpetrator in relation to the punishment applicable at the time of the commission of the criminal offence.
Article 4(a) of the CC of BiH prescribes that Articles 3 and 4 of the CC of BiH [which stipulate the principle of legality and the principle of time constraints regarding applicability] shall not prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of international law … , thus providing for exceptional departure from the … mandatory application of a more lenient law in the proceedings concerning criminal offences …
[Although at] the time of the commission of the offences, crimes against humanity were not explicitly prescribed under criminal codes in Bosnia and Herzegovina … irrespective of whether viewed from the viewpoint of customary international law or of “principles of international law”, it is indisputable that crimes against humanity constituted a criminal offence in the period relevant to the indictment, and that the principle of legality has been met. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Šimšić case, Judgment, 7 August 2007, pp. 42–45.
Bosnia and Herzegovina
In 2007, in the Lučić case, the Panel of the Court of Bosnia and Herzegovina stated:
The Court finds the principles of legality and of time constraints regarding applicability relevant to determine the substantive law applicable at the time the criminal offences of crimes against humanity were committed, while taking into account the then existent international law provisions.
[I]t is forbidden to impose a heavier penalty than the one applicable at the time when the criminal offence was perpetrated. Hence, these provisions [Articles 3 and 4 of the Criminal Code of Bosnia and Herzegovina (CC BiH), Article 7(1) of the European Convention on Human Rights (ECHR) and Article 15(1) of the International Covenant on Civil and Political Rights (ICCPR)] prescribe a ban on imposing a heavier penalty, failing to determine obligatory application of a more lenient law to the perpetrator, in comparison to the penalty applied at the time of the commission of the criminal offence. This is the rule of the principle of legality, but there is an exception to the principle of legality.
Article 4a) of the CC BiH prescribes that Articles 3 and 4 of the CC BiH shall not prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of international law.
In sum, Article 4a) of the CC BiH adopted, in fact, the provisions of Article 7(2) of the ECHR and Article 15(2) of the ICCPR thus explicitly enabling exceptional departure from the principle referred to in Article 4 of the CC BiH, as well as departure from the obligatory application of a more lenient law in the proceedings concerning criminal offences according to international law, concerning the charges including the violation of the rules of international law. Such a position was taken in the hitherto jurisprudence of the Court of BiH [Bosnia and Herzegovina], following international jurisprudence.
In practice, the [European Court of Human Rights] finds the violation of Article 7 [of the ECHR] when, by retroactively applying the new law which has direct or indirect effect (e.g. the provisions of recidivism) on sentencing, the convicted person is punished with a heavier penalty than the one the person would face at the time of the perpetration of the criminal offence.
… The [European Court of Human Rights] took the rule and the exception to the principle of legality as equally well recognized and making part of the same principle …
According to the jurisprudence of the [European Court of Human Rights], one cannot refer to a violation of Article 7 of the Convention [ECHR] in the event when the applicant has been imposed a life imprisonment or the penalty of long-term imprisonment for a criminal offence for which the death penalty was prescribed at the time of the commission, although a life imprisonment or a long-tern imprisonment were not prescribed under the law that was in force at the time, because life imprisonment is obviously more lenient than the death penalty.
[R]egardless of whether viewed from the aspect of customary international law, international treaty law or “the principles of international law”, it is indisputable that war crimes, including crimes against humanity, constituted a criminal offence at the critical time. In other words the principle of legality is complied with, in the sense of both nullum crimen sine lege and nulla poena sine lege. 
Bosnia and Herzegovina, Court of Bosnia and Herzegovina, Lučić case, Judgment, 19 September 2007, pp. 56–61.
[footnotes in original omitted]
Canada
In 2013, in the Sapkota case, Canada’s Federal Court dismissed a request for review of a decision denying refugee protection to the applicant on grounds of complicity in crimes against humanity in Nepal between 1991 and 2009. While reviewing the submissions of the respondent, Canada’s Minister of Citizenship and Immigration, the Court stated: “The Respondent notes that the Rome Statute of the International Criminal Court … is endorsed in Canada as a source of customary law.” 
Canada, Federal Court, Sapkota case, Reasons for Judgment and Judgment, 15 July 2013, § 28.
Colombia
In 2007, in the Constitutional Case No. C-291/07, the Plenary Chamber of Colombia’s Constitutional Court stated:
Taking into account … the development of customary international humanitarian law applicable in internal armed conflicts, the Constitutional Court notes that the fundamental guarantees stemming from the principle of humanity, some of which have attained ius cogens status, … [include] the obligation to respect … the principle of legality regarding crimes and penalties. 
Colombia, Constitutional Court, Constitutional Case No. C-291/07, Judgment, 25 April 2007, p. 112.
[footnote in original omitted]
Democratic Republic of the Congo
In March 2006, in the Bongi Massaba case, a case against a captain of the armed forces of the Democratic Republic of the Congo, the Military Garrison Court of Ituri at Bunia held:
III. Applicable law
Whereas the Military Garrison Court of Ituri has been seized by referral decision of the Garrison Military Auditor with two charges falling under the competence of the International Criminal Court, namely, first, war crimes as provided for in article 8.2.b.xvi and article 77, and second, article 8.2.a.i and article 77 of the Rome Treaty on the Statute of the International Criminal Court of 17 July 1998;
Whereas that Statute represses the crimes of genocide, crimes against humanity and war crimes committed since the first of July 2002, the crimes of aggression not yet having been defined;
Whereas the Democratic Republic of the Congo has ratified that treaty by Decree-law No. 0013/002 of 30 March 2002;
Whereas the Military Penal Code of 18 November 2002, Law No. 024/2002, in its articles 161 to 175, provides for the crimes of genocide, crimes against humanity and war crimes;
Whereas, in consequence, the material competence of the International Criminal Court is not exclusive, by virtue not only of the principle of complementarity and subsidiarity of that Court in relation to domestic jurisdictions, in the sense that it follows from the reading of that Statute that the domestic jurisdictions are preferred to the ICC, which only intervenes under the conditions determined by that Statute;
Whereas, however, that domestic legislation, in this instance the Military Penal Code of 18 November 2002, in force since 30 March 2003, contains a clear gap by, in fact, not punishing war crimes for which there is no penalty provided;
Whereas, obviously, the Congolese legislator did not at all have the intention to leave unpunished this atrocious crime, whose great gravity it had recognized by ratifying the Treaty of Rome on the Statute of the Court;
Whereas, in consequence, that omission of penalization is, in the end, only a purely material error …;
Whereas, according to article 2 of the Military Penal Code, “No offence can be punished with a penalty not provided for by the law before the offence was committed”;
Whereas, in this instance, indeed, that domestic law has never provided for a penalty for war crimes, not even by the technique of cross-reference;
Whereas, under these conditions, it is necessary to seek to fill these gaps in the domestic legislation by relying on the Rome Treaty on the Statute of the International Criminal Court ratified by the DRC, in order better to attain the aim the Congolese legislator had, namely to have war crimes punished by the military jurisdictions on the national level (read point VII of the legislative background to Laws No. 023 and 024/2002 of 18 November 2002 in the Journal Officiel of the DRC, special issue of 30 March 2003);
Whereas, according to article 215 of the Constitution of the RDC promulgated on 18 February 2006, it is stipulated that “the regularly concluded treaties and international agreements have, from the time of their publication, an authority superior to that of the law, without reserve to the application of the treaty or agreement by the other party”;
Whereas, for this reason, the Military Garrison Tribunal of Mbandaka, seized with a case concerning crimes against humanity provided for by article 166 of the Military Penal Code, in its interlocutory decision pronounced on 12 January 2006, RP No. 086/05, RMP No. 279/GMZ/WAB/2005, has decided to try that charge in accordance with the provisions and penalties of the Rome Statute, which it considered to be more clearly defined, better adapted by having at its disposal mechanisms for the protection of the rights of victims, less severe in as much as it does not know the death penalty, in contrast to the Military Penal Code;
Whereas, in the present case, these reasons justify the prosecution in directly relating its legal definitions of the charges to the Rome Statute, whose ratification by the DRC is part of the armory of laws of the Democratic Republic of the Congo by virtue of legal monism with primacy of international law, in this instance the ICC Statute which inspired the introduction into the Military Penal Code of the crimes falling under its jurisdiction. 
Democratic Republic of the Congo, Military Garrison Court of Ituri, Bongi Massaba case, Judgment, 24 March 2006.
In November 2006, on the defendant’s appeal, the Military Court of the Eastern Province also held:
Applicable Law
Whereas the Military Court of the Eastern Province is seized with the appeal of the defendant Blaise Bongi Massaba, convicted by the Military Garrison Tribunal of Ituri on the basis of two offences under the competence of the International Criminal Court …;
Whereas the Democratic Republic of the Congo has ratified that treaty by Decree-law No. 0013/2002 of 30 March 2002;
Whereas the Military Penal Code issued by Law No. 024/2002 of18 November 2002, in its articles 161 to 175, provides for:
- crimes of genocide,
- crimes against humanity,
- and war crimes;
Whereas in view of the principle of complementarity and subsidiarity, which rules the International Criminal Court, its material competence is not exclusive;
Whereas, according to the reading of the Rome Treaty, domestic jurisdictions are preferred to the International Criminal Court, which only intervenes under the conditions determined by the same treaty;
Whereas article 173 of the Military Penal Code provides the content of the notion of war crime, but is mute as regards the penalty to inflict, i.e. the incrimination of war crimes is without penal sanction;
Whereas the Congolese legislation could not at all leave unpunished all these atrocities whose gravity it recognized by the ratification of the Rome Treaty on the Statue of the Court;
Whereas according to the terms of article 2 of the Military Penal Code: “No offence can be punished with a penalty not provided for by the law before the offence was committed”;
Whereas, in this instance, article 173 of the Military Penal Code has never provided for a penalty for war crimes, not even by the technique of cross-reference;
Whereas the competence of the Military Court of the Eastern Province cannot have the recognition of these odious crimes by the Military Penal Code as its basis;
Whereas, according to the reading of the legislative background of Laws No. 023 and 024/2002 of 18 November 2002 published in the Journal Officiel of the Democratic Republic of the Congo, special issue of 30 March 2003, point VIII, there is cause to fill this gap of the Congolese legislation by relying on the Rome Treaty on the Statute of the International Criminal Court, ratified by the Democratic Republic of the Congo, and to resort, for the repression of these international crimes, to article 153, paragraph 4 of the Constitution of the Democratic Republic of the Congo, which declares that the Courts and Tribunals, civilian and military, apply international treaties duly ratified, laws, regulations as long as they are in accordance with the laws, as well as custom as long as it is in accordance with public order and morals;
Whereas, based on this constitutional provision, the Military Garrison Tribunal of Mbandaka, in its interlocutory decision RP No. 086/05, RMP No. 279/GMZ/WAB/2005, pronounced on 12 January 2006, seized with a case concerning crimes against humanity provided for by article 166 of the Military Penal Code, has decided to try that charge by relying on the provisions and penalties of the Rome Statute;
Whereas that Tribunal considered the provisions of the Rome Treaty to be more clearly defined and better adapted by having at its disposal mechanisms for the protection of the rights of victims,
Whereas the Military Court of the Eastern Province considers that the provisions of the Rome treaty are more humanizing, in fact, less severe as regards the penalty, the death penalty there being unknown, in contrast to the Military Penal Code.
Whereas it is for these reasons that the Military Court of the Eastern Province has decided to apply the Rome Treaty, whose ratification by the Democratic Republic of the Congo integrates it into the legislative armory, in accordance with article 215 of the Constitution of the Democratic Republic of the Congo. 
Democratic Republic of the Congo, Military Court of the Eastern Province, Bongi Massaba case, Judgment on Appeals, 4 November 2006.
Democratic Republic of the Congo
In August 2006, in the Kahwa Panga Mandro case, the Military Garrison Court of Ituri at Bunia held:
a) The applicable law
Whereas, newly introduced into positive Congolese law first by Decree-Law No. 003/2002 of 30 March 2002 concerning the ratification of the Rome Treaty of 17 July 1998 on the Statute of the International Criminal Court, the crimes against humanity and the war crimes repressed by that Court on the territory of every State party, among them the Democratic Republic of the Congo, were, on 30 March 2003, date of the entry into force of Law No. 024/2002 of 18 November 2002 on the Military Penal Code, placed under the sole competence of the military courts, as stipulated in Article 161 of that Law;
Whereas, as regards the war crimes provided for in Articles 173 to 175, it follows that the Congolese legislator intended that for their repression the military judge refer to the penalties provided in internal law for the various violations of the laws of the Republic that, in view of that Military Penal Code, merely become war crimes because of the fact that they are committed during war in violation of the laws and customs of war;
Whereas, however, the present court will refer to the definition of these crimes such as it is given by the Rome Treaty mentioned, for the reason that the Constitution of the Democratic Republic of the Congo of 18 February 2006, in its Articles 215 and 153, paragraph 4, respectively, stipulates as follows:
“the international treaties and agreements regularly concluded have, from the time of their publication, an authority superior to that of the laws, without reserve of the application of the treaty or agreement by the other party”
“the Courts and Tribunals, civilian and military, apply the international treaties duly ratified, laws, regulations provided that they are in accordance with the laws, as well as custom provided that it is not contrary to the public order or morality”;
Whereas, further, it is already in this sense that in its judgement rendered on 24 March 2006, under RP No. 018/2006, the present Tribunal convicted captain Blaise Bongi Massaba for war crimes on the basis of the Rome Treaty of 18 July 1998 on the Statute of the International Criminal Court …
Whereas, consequently, in the present case this Tribunal again will safely apply the essential provisions of the Rome Statute, on crimes against humanity and war crimes. 
Democratic Republic of the Congo, Military Garrison Court of Ituri, Kahwa Panga Mandro case, Judgment, 2 August 2006.
Democratic Republic of the Congo
In 2009, in the Kyungu Mutanga case, the Military Garrison Court of Haut-Katanga was called upon to decide on several criminal charges against Kyungu Mutanga and others, including charges on war crimes and crimes against humanity allegedly committed as members of the armed group Mai-Mai. Regarding the applicable law, the Court stated:
[Crimes against humanity and war crimes] are provided for in both the … [Military Penal Code (2002)] and the … 1998 … ICC … Statute.
The Court notes that article 153 of the [2006] Constitution clearly provides that “in addition to laws, civil and military courts shall apply also international treaties and agreements which have been duly ratified”.
As the DRC authorised the ratification of the … 1998 … ICC … Statute through its Decree-Law No. 0013/2002 of 3 March 2002, the Court has thus to deal with the fact that there are two conflicting laws.
In the present case, the crimes against humanity and war crimes for which the defendants are charged, are regulated by two conflicting legal instruments with regard to the definitions of such crimes and applicable penalties.
… The domestic law confuses war crimes and crimes against humanity, which, on the other hand, are clearly defined in the [1998] ICC … Statute.
… The domestic law is stricter in the applicable penalty than the international legal instrument.
The former provides for the death penalty, while the latter discards the death penalty in favour of a life sentence.
Thus, the Court finds that the [1998] … ICC … Statute is very favourable to the defendants.
It discards, in the present case, the [application of the] … Military Penal Code [(2002)] in favour of the [application of the] … 1998 … ICC … Statute exclusively with regard to the charges of crimes against humanity and war crimes brought against the defendants. 
Democratic Republic of the Congo, Military Garrison Court of Haut-Katanga, Kyungu Mutanga case, Judgment, 5 March 2009, pp. 69–70.
Democratic Republic of the Congo
In 2009, in the Basele Lutula and Others case, the Military Garrison Court of Kisangani convicted Mai-Mai militia members of various crimes, including the crime against humanity of rape. Regarding the applicable law, the Court stated:
Considering that the Public Prosecutor’s Office upheld the category of crime against humanity by rape provided for and punished by article 7(1)(a)-1 of the … [1998 ICC] Statute … ;
Considering that articles 165 and 169 of the Penal Code provide for and punish the same crime;
Considering that the Democratic Republic of the Congo ratified the … [1998 ICC] Statute through Decree No. 0013/002 of 20 March 2002;
Considering that article 215 of the Constitution … (2006) provides that “regularly concluded international treaties and agreements … have a higher authority than laws … ”;
Considering that the … [1998 ICC] Statute, contrary to the statutes of the ad hoc tribunals, namely the ICTR and the ICTY, and [contrary to] … [the Military Penal Code (2002)], is not ambiguous regarding the definition of … terms, in particular “attack” [and] “widespread or systematic character” …
Considering that the provisions of the … [1998 ICC] Statute on those crimes are soft to the defendants and favourable to the victims;
Considering that in its judgement … RDN No. 086/05, RMP No. 279/2005 of 12 January 2005, the … [Military Garrison Court of Mbandaka], to which [a case on] crimes against humanity had been referred pursuant to article 166 of the Military Penal Code [(2002)], decided to … [apply] the provisions of the … [1998 ICC] Statute because they are not ambiguous;
… [I]n the present case, in view of the above, the Court will apply the relevant essential provisions of the … [1998 ICC] Statute. 
Democratic Republic of the Congo, Military Garrison Court of Kisangani, Basele Lutula and Others case, Judgment, 3 June 2009, pp. 20–21.
France
In 2003, in the Aussaresses case, France’s Criminal Law Chamber of the Court of Cassation held:
Finding on the appeal lodged by the Movement against Racism and for Friendship between Peoples Mouvement contre le Racisme et pour l’Amitié entre les Peuples – MRAP], civil party,
Against the decision of the investigating chamber of the Court of Appeal of Paris of 14 December 2001, which confirmed the order of the investigating judge, refusing to hold an investigation upon its criminal complaint against an unnamed person for a count of crimes against humanity;
Whereas it follows from the decision attacked and from the documents of the proceedings that the Movement against Racism and for Friendship between Peoples, constituting itself as civil party, brought a criminal complaint against unnamed person for crimes against humanity, because of torture and summary executions which, in a book published on 3 May 2001, General Paul X … revealed having carried out or having ordered to be carried out against the civilian population, in Algeria between 1955 and 1957, while he was an intelligence officer in the service of the French army;
Whereas, to confirm the order, the investigating chamber upholds, in the grounds under appeal, that, impossible to be prosecuted under the classification of crimes against humanity, the denounced acts fall under the provisions of Law Nr. 68-697 of 31 July 1968 on amnesty;
Whereas by pronouncing thus, the judges have justified their decision;
Whereas the provisions of the law of 26 December 1964 and those of the Statute of the International Military Tribunal at Nuremberg, annexed to the London Charter of 8 August 1945, only concern the acts committed on behalf of the European Axis countries;
Whereas, furthermore, the principles of legality of crimes and penalties and of non-retroactivity of a more severe criminal law, set out by Article 8 of the Declaration of the [1789] Declaration of the Rights of Man and of the Citizen, Article 7-1 of the European Convention on Human Rights, Article 15-1 of the International Covenant on Civil and Political Rights, 111-3 and 112-1 of the Penal Code, are an obstacle to the application of Articles 211-1 to 212-3 of that Code, repressing crimes against humanity, to acts committed before their entry into force, 1 March 1994;
Whereas international custom cannot make up for the absence of a criminalizing text, under the classification of crimes against humanity, the acts denounced by the civil party;
From which follows that the appeal must be rejected. 
France, Court of Cassation, Aussaresses case, Appeal Nr. 02-80719, Judgment, 17 June 2003.
On the same day, the Court of Cassation, on the same grounds, rejected an appeal lodged by the International Federation for Human Rights [Fédération International des Ligues des Droits de l’Homme – FIDH] against a decision of the investigating chamber of the Court of Appeal of Paris relating to the same facts. 
France, Court of Cassation, Aussaresses case, Appeal Nr. 02-83986, Judgment, 17 June 2003.
Hungary
In Decision No. 53/1993, the Constitutional Court of Hungary stated:
4. The prosecution and punishment of war crimes and crimes against humanity may only proceed within a framework of legal guarantees; it would be self-contradictory to protect human rights without such guarantees. But these international guarantees cannot be replaced or substituted by the legal guarantees of domestic law.
a) International law applies the guarantee of nullum crimen sine lege to itself, and not to the domestic law. “Customary international law,” “legal principles recognized by civilized nations,” “the legal principles recognized by the community of nations,” is such a lex, or a body of written and unwritten laws, which classifies certain behavior prosecutable and punishable according to the norms of the community of nations (via international organizations or membership in a given community of states), irrespective of whether the domestic law contains a comparable criminal offense, and whether those offenses have been integrated into an internal legal system by that country’s accession to the pertinent international agreements …
Article 15 § (1) of the International Covenant on Civil and Political Rights – which, in its content, matches article 7 § (1) of the European Convention for the Protection of Human Rights and Fundamental Freedom – obligates member states to uphold unconditionally the principles of nullum crimen sine lege and nulla poena sine lege. The reference by international law to the criminal offense defined (“[n]o one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time it was committed”) has been interpreted by legal scholars to refer only to those criminal offenses which are undoubtedly punishable by domestic law, either via ratification or direct absorption.
According to article 15 § (2) of the Convention “[n]othing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.” (The content of article 7 § (2) of the European Convention is similar, with the distinction that the latter substitutes “civilized nations” for the term “community of nations”). This exception, is what makes possible the prosecution of the aforenoted and described sui generis criminal offenses defined by international law even by those member states whose domestic system of law does not recognize the definition or does not punish that action or omission. It follows logically, therefore, that such acts must be prosecuted and punished in accordance with the conditions and requirements imposed by international law. The second section of both (International and European) Conventions evidently break through the penal law guarantees of domestic law, also demanded by international law, especially as article 4 § (2) of the International Convention and article 15 § (2) of the European Convention both mandate that the principles of nullum crimen-nulla poena be given effect, even in situations of war or public emergencies threatening the life of the nation. For those states which incorporate the international legal norms concerning war crimes and crimes against humanity subsequent to the commission of these crimes, section 2 of the aforementioned articles authorize the retroactive application of statutorily enacted penal laws in the state’s domestic legal system. But these acts must be adjudged punishable at the time of their commission by international, and not by domestic law. 
Hungary, Constitutional Court of Hungary, Decision No. 53/1993, 13 October 1993, Reasoning, Part IV, § 4.
The Court further stated:
The international legal regulation of war crimes and crimes against humanity pays no heed to the principle of nullum crimen given effect by domestic law when it makes the punishment of these offenses independent of the fact whether or not they constituted a criminal offense in the domestic penal law at the time of their commission. But this action is contradictory only if one sought to harmonize international and domestic law by insisting that international law accommodate the domestic one. But in the case at hand, what is at stake is not simply that with respect to war crimes and crimes against humanity an exception is made from the otherwise unconditionally applied domestic rule of nullum crimen sine lege. Thus, the question cannot be limited to whether the particular regulations aimed at redressing the violations of international humanitarian law may be integrated into article 57 § (4) of the Constitution. The constitutional question must be raised and answered by considering that article 7 § (1) of the Constitution mandates that alongside with the domestic law, another legal system, certain rules of international law, must concurrently be given effect … It is isolation from or rejection of international law which is what would be contrary to article 7 § (1) of the Constitution. But what occurs in this case is not the abandonment or destruction of the principle of nullum crimen but its limitation to the sphere of domestic law. Within its own system, international law demands that certain criminal acts be classified – based on general principles recognized by the community of nations, interpreted by what has been referred to above as international customary law – as war crimes or crimes against humanity at the time of their commission. Through the penal power of the Hungarian state it is, in fact, the penal power of the international community which is given effect within the framework of conditions and guarantees provided by international law. Domestic substantive law may be applied only to the extent international law expressly commands it (for instance, as is the case with imposition of sentencing). No domestic law confronted with a conflicting and express peremptory rule of international law (jus cogens) may be given effect.
The harmonization of domestic and international penal law may proceed in numerous ways. It is possible to enact express rules regarding the independence of the two systems. This is what the International and European Conventions did in their own sphere of jurisdictions when stating that the international obligation assumed for the unconditional application of the principle of nullum crimen in domestic criminal law is not violated or destroyed by giving effect to international legal rules on war crimes and crimes against humanity. This interpretive or “permissive” regulation by the Conventions facilitates the integration of the international rule into the domestic system of law – what the Hungarian Constitution labels “harmony” or “consonance”. Of course, the above mentioned Conventions can only facilitate the integration from the side of international law. The domestic aspect of the “harmony” or “consonance” must be addressed by the domestic law. Given the absence of an interpretive provision in the Hungarian Constitution similar to the provisions of the Convention noted above (and which rule, for instance, is found in the Portuguese Constitution), the Hungarian Constitution also permits the interpretation of international law. This is, in fact, a constitutional requirement by article 7.
On the basis of the reasoning above, there is no contradiction between article 57 § (4) and article 7 § (1) of the Constitution and, instead, they must be interpreted in light of one another. Alongside with the unconditional applicability of the principle of nullum crimen to domestic law, article 7 § (1) brings about the constitutional realization of international penal law’s rules pertaining to war crimes and crimes against humanity. 
Hungary, Constitutional Court of Hungary, Decision No. 53/1993, 13 October 1993, Reasoning, Part V, § 2.
Indonesia
In the Abilio Soares case before the Ad Hoc Human Rights Tribunal for East Timor in 2002, a former governor of Timor-Leste was charged with crimes against humanity. The charges were based on the law establishing the Tribunal, which entered into force in 2000, subsequent to the events for which the accused was on trial. An objection based on the principle of non-retroactivity lodged by the defence was rejected by the Court, which stated:
Concerning the application of the retroactive principle:
In considering, that the prohibition of retroactive law (ex post facto) is a basic right that is a non derogable right, as stipulated in Article 28 (i) 2nd Amendment 1945 Constitution and Article 4 Law No. 39 year 1999 concerning Human Rights, is universal and is derived from Article 11 of the Universal Declaration of Human Rights. In [hearings] that discussed the draft of this Article 11, which reads:
It states that the prohibition shall not prejudice the trial and punishment of any person for any act or omission which, at the time it was committed, was criminal according to general principles of law recognized by the community of nations.
The above provision was later expressed in Article 15 verse (2) of the International Covenant on Civil and Political Rights/ICCPR. The same is also found in Article 7 verse (2) of the European Convention on Human Rights/EHCR. The inclusion of the provision in the two instruments above was intended to remove any doubt as to the legality of the rulings of the Nuremberg and Tokyo Tribunals, which some consider as the application of law ex post facto.
In considering that in later developments the practice in the International Criminal Tribunal for the Former Yugoslavia/ICTY and the International Tribunal for Rwanda/ICTR indicates that the two applied legal provisions formed after the act is committed, and in a certain place. ICTY, which was established through UN Security Council Resolution No. 827 on May 25, 1993, through its Statute has the power to try crimes committed since 1991.
Article 1 of the ICTY Statute, the International Criminal Tribunal for the Former Yugoslavia: “shall have the power to prosecute persons responsible for serious violations of international humanitarian law committed in the territory of the former Yugoslavia since 1991 in accordance with the provisions of the present Statute”.
Similarly in Rwanda, the ICTR Statute states that the Tribunal can prosecute acts of genocide and violation of humanitarian laws taking place in Rwanda from January 1, 1994 to December 31, 1994, as provided in UN Security Council Resolution No. 955 dated November 8. 1994.
The International Tribunal for Rwanda “shall have the power to prosecute persons for having committed serious violations of article 3 common to the Geneva Conventions of 12 August 1949 for the protection of victims of war and to Additional Protocol II hereto of 8 June 1977 …” Article 4 of the Statute of Rwanda Tribunal.
In considering, that in Machteld Boot’s thesis headed “Nullum Crimen Sine Lege and the Subject Matter Jurisdiction of the International Criminal Court; Genocide, Crimes Against Humanity, War Crimes”, dated 15 February 2002, on page 39, states:
that the drafters of the Rome Statute were also still inspired by international conventions, international custom as evidence of general practice accepted as law, and general principles of law recognized by civilized nations;
Therefore it may be concluded that the legality principle is not absolutely valid and there may be exceptions to this principle by stating that the retroactive principle applies in certain cases.
In considering, that an Ad Hoc Tribunal was also conducted for criminals in the former Yugoslavia and Rwanda under special clauses, that determine jurisdiction over crimes in certain locus and tempus, namely;
In considering, that the Ad Hoc Human Rights Tribunal in Central Jakarta is also based on Article 43 of Law No. 26 Year 2000, that was later endorsed by the Indonesian House of Representatives through Keputusan DPR-RI Nomor 55/DPR-RI/III/2001 dated March 12 2001, Concerning Approval by the People’s Representative Council of the Republic of Indonesia of the Proposal to Form an Ad Hoc Human Rights Tribunal for Suspected Serious Human Rights Violations in East Timor and Serious Human Rights Violations in the 1984 Tanjung Priok Case, in conjunction with Presidential Instruction (Keppres) No. 96 Year 2001 concerning Amendments to Keppres. No. 53 year 2001 Concerning Formation of an Ad Hoc Human Rights Tribunal in Central Jakarta, that reads:
Article 2: The Ad Hoc Human Rights Tribunal as referred to in Article 1 is authorized to examine and rule on serious Human Rights violations occurring in East Timor in the legislated regions of Liquisa, Dili, and Suai in April 1999 and September 1999, and occurring in Tanjung Priok in September 1984;
Therefore the retroactive principle may also be valid to examine and try serious human rights violations cases in the prescribed periods, in particular as in the Penjelasan Undang-undang is clearly stated that: “in other words the retroactive principle may be applied to protect human rights itself under Article 28 jo verse (2) Undang-undang Dasar 1945”. 
Indonesia, Ad Hoc Human Rights Tribunal for East Timor, Abilio Soares case, 7 August 2002, pp. 52–53.
The defendant’s petition to the Constitutional Court on the same issue in 2005 was also unsuccessful. The Court stated:
Considering whereas the principal issue of the a quo petition concerns the application of Article 43 Paragraph (1) of the Human Rights Court Law which regulates the Ad Hoc Human Rights Court having the authority to examine gross human rights violations occurring prior to the enactment of the a quo law, on the basis of which the Petitioner has been tried and sentenced, thus the Petitioner claims that that his constitutional rights have been impaired since he has been tried and sentenced based on legal provisions which apply retroactively. According to the Petitioner, this is contradictory to Article 28I Paragraph (1) of the 1945 Constitution which states, “The right to life, the right not to be tortured, the right of freedom of thought and conscience, the right to have a religion, the right not to be enslaved, the right to be recognized as a person before the law, and the right not to be prosecuted under retroactive laws shall constitute human rights which cannot be reduced under any circumstances whatsoever”. Therefore, Article 43 Paragraph (1) of the a quo law is petitioned to the Court to be declared as having no binding legal force;
Considering whereas Article 43 Paragraph (1) of the Human Rights Court Law states, “gross human rights violation which occurred prior to the enactment of this law, shall be examined and decided by an ad hoc Human Rights Court”, unarguably has a legal provision that applies retroactively. However the legal problem that must be considered and decided by the court in the a quo petition is whether such provision is automatically contradictory to Article 28I Paragraph (1) of the 1945 Constitution …
Considering whereas the background of the establishment of the Human Rights Court is as described above and what has to be considered by the court now is: whether the establishment of the Ad Hoc Human Rights Court with retroactive legal provisions is contradictory to Article 28I of the 1945 Constitution, as petitioned by the a quo Petitioner. To answer this question, firstly it needs to be answered: whether the right not to be prosecuted by any law which applies retroactively is an absolute right, as textually formulated in Article 28I Paragraph (1) of the 1945 Constitution;
Considering whereas the provision of Article 28I Paragraph (1) of the 1945 Constitution states that the right not to be prosecuted under retroactive law shall constitute human rights which cannot be reduced under any circumstances whatsoever. Although such literal formulation creates an impression as if the right not to be prosecuted under a retroactive law is absolute, in accordance with the history of its formulation, Article 28I Paragraph (1) can not be interpreted as standing in its own, but rather, it must be read together with Article 28J Paragraph (2). As such, it will be clear that, systematically, human rights – including the right not to be prosecuted under a retroactive law – is not absolute, because in exercising his right and freedom, every person must respect the human rights of others and must submit to the limitation stipulated in laws with the sole purpose of guaranteeing the respect for and enforcement of the rights and freedom of others, as well as to “meet fair demand in accordance with the consideration of morality, religious values security and, public order in a democratic society” as provided for in Article 28 Paragraph (2). By reading Article 28 I Paragraph (1) together with Article 28 J Paragraph (2) it is noticeable that the right not to be prosecuted by retroactive laws is not absolute, and in order to “meet the fair demand in accordance with considerations of morality, religious values, security and order” and such right can be set aside.
Also considering that a retroactive application of a law does not immediately make the law contradictory to the Constitution and instantly loses its binding legal force. Such application also does not immediately constitute human rights violation, instead it must be assessed based on two factors or requirements that must be met in the retroactive application of laws;
Firstly, the magnitude of public interest that must be protected by the law;
Secondly, the weight and nature of the rights violated as a result of such application of law is smaller than the violated public interest;
Considering whereas the above-mentioned crimes are contradictory to the spirit to enforce and highly uphold humanity and justice, which are clearly stated in the preamble of the 1945 Constitution, and at the same time they are also contradictory to the general principles of law recognized by civilized nations. Therefore, the overriding of the principle of non-retroactivity on such crimes is not contradictory to the 1945 Constitution; as the constitution of a civilized nation, the spirit of the 1945 Constitution in fact mandated the enforcement of humanity and justice; hence the above described crimes against humanity must be eradicated. When the demand to uphold humanity and justice is hindered by the principle of non-retroactivity – which historically and initially had the background of the intent to protect individual human beings’ interest from arbitrary actions of absolute rulers – hence the overriding of the principle of non-retroactivity becomes an unavoidable action because the interests which are to be saved through such overriding are the interests of human beings as a whole whose value exceeds the interest of an individual human being;
Considering whereas the establishment of the ad hoc Human Rights Court, as a forum to adjudicate perpetrators of crimes categorized as “the most serious crimes of concern to the international community as a whole”, as regulated in Article 43 Paragraph (1) of the Human Rights Court Law, aside from being justifiable according to the 1945 Constitution, it is also justifiable by international legal practice and development, which among others is shown by the establishment of the ad hoc Criminal Tribunal in the former Yugoslavia, namely the International Criminal Tribunal for the former Yugoslavia (ICTY) and in Rwanda, namely the International Criminal Tribunal for Rwanda (ICTR). The ICTY was formed (in 1993) with the jurisdiction to adjudicate perpetrators of war crimes and crimes against humanity, whose tempus delicti was limited after January 1, 1991 and its locus delicti being the territory of former Yugoslavia. Meanwhile ICTR was formed (in 1994) with the jurisdiction to adjudicate perpetrators of genocide crime and other serious crimes against international humanitarian law, whose tempus delicti was as from January 1 to December 31, 1994, whereas its locus delicti being Rwanda and its neighbouring states. The two ad hoc courts, ICTY and ICTR, were both set up based on the Resolution of the United Nations Security Council, even though formed after the occurrence of the event, substantially with the jurisdiction actually being on violations which are considered as crimes under international law (vide Otto Triffterer, Commentary on the Rome Statute of the International Criminal Court, Nomos Verlagsgesellschaft, Baden-Baden, 1999, page 324). Such is also the case with the ad hoc Human Rights Court formed based on Article 43 Paragraph (1) of the Human Rights Court Law, even though formed after the occurrence of the incident or violation, the types of violations which are under its jurisdictions ( ratione materiae) are actually violations which were crimes prior to the establishment of the ad hoc Human Rights Court, namely genocide and crimes against humanity in this case;
Considering further that the Human Rights Court Law only includes two types of crimes with respect to which the principle of non-retroactivity can be overridden, namely genocide and crimes against humanity. The a quo law does not include war crimes and aggression crimes, although according to international customary law these two types of crimes are also categorized as the most serious crimes of concern to the international community as a whole. This can be understood because at that time, there was no legal need to regulate the two types of crimes in the a quo law, particularly Article 43 Paragraph (1), because it was not relevant to the context of the intent and purpose of the establishment of the ad hoc Human Rights Court;
Considering whereas based on the above description, some of the arguments of the Petitioner which are used as the basis for the refusal of the overriding of the principle of non-retroactivity are justifiable as long as they concern ordinary crimes or extraordinary crimes which can be sufficiently tried through a regular court forum without overriding the non-retroactivity principle. However, the arguments can not be used to develop axiomatic legal construction leading to a conclusion that the right not to be prosecuted based on a retroactive law is an absolute human right. Because, if such thought construction is used, actions categorized as extraordinary crimes which are universally considered as the most serious crimes of concern to the international community as a whole, including crimes regulated in the a quo law, are very likely to escape legal prosecution if the law does not firmly regulate such actions as crimes. If that happens, violations have occurred on a fundamental principle universally accepted as a legal principle namely “there shall be no crimes allowed to pass without punishment” (aut punire aut dedere). Axiomatic legal construction which makes the principle of non-retroactivity absolute, rationally, must also be interpreted as a rejection of the transitional justice mechanism which is the resolution mechanism for violations of law occurring in the past, especially gross human rights violations. Because, the transitional justice mechanism, regardless of the extent, is certain to contain the element of the overriding of the principle of non-retroactivity. 
Indonesia, Constitutional Court, Abilio Soares case, 2 March 2005, pp. 6–7, 10–14, and 18–22.
In their dissenting opinions, three of the nine justices of the Court would have upheld the principle of non-retroactivity and granted the petition. 
Indonesia, Constitutional Court, Abilio Soares case, 2 March 2005, pp. 23–30.
Iraq
In its judgment in the Al-Dujail case in 2006, the Iraqi High Tribunal stated:
Is the principle of criminal legality (Crimes and Penalties according to legal provisions) applied in international criminal law as the fact is in the internal law of each country? Is it not permissible in international law to punish only for actions given the nature of crime by international law at the time those actions were committed?
The answer to these questions requires more efforts to reach the truth from the legal side. In 1948 and specifically on September 10 of the same year, the Universal Declaration of Human Rights was issued, adopted and published publicly by the U.N. general assembly resolution n° 217 thousand (D-3) stipulated in article February 11 therein that “any person shall not be condemned by a crime because of any action or refraining from action that was not in due time considered a crime by virtue of the national or international law, also no penalty is imposed thereon more intensive than the penalty in force at the time the criminal action was committed”.
This Universal Declaration of Human Rights is very important in adopting and determining the concept of the principle of the legality of crimes and penalties and the principle of non-retroactivity in international criminal law. The concept of these principles by virtue of the declaration is not limited to what is adopted by the internal laws of the different countries as a necessity that the action should be stipulated as a punishable crime when committed in the national laws of their countries, but instead the concept of this principle in international criminal law extends to comprise international crimes.
So the action or prevention should form an international crime punishable by virtue of international law, also this action or refraining from action shall be considered (an international crime) when committed, and the same if the origin of this crime and penalty exists in international customs or in international conventions and treaties.
Our court believes that what is stated in the Universal Declaration of Human Rights is at least obligatory for the member countries of the U.N. and Iraq is a constituent member in this international organization and therefore it is obligatory according to the principles stated in this proclamation without the need to stipulate it in the interior law.
This opinion endorses the provisions of article 15 (of the International Covenant on Civil and Political Rights) which was adopted and presented for signature and ratification and enrolment by the UN General Assembly resolution (2200) dated December 16, 1966 effective as of March 23, 1976 ratified by Iraq in 1971.
The aforementioned article stipulated that:
“1) any person shall not be condemned by a crime because of any action or refraining from action that at the time did not constitute a crime by virtue of the national or international law, also no penalty is imposed thereon more intensive than the penalty in force at the time the criminal action was committed, and if it happened after the committed crime, since the law stipulates a less commuted penalty, then the perpetrator of the crime shall benefit from the commutation.
2) Nothing in this article infringes on the trial and the punishment of any person for any action or refraining from action upon committing a crime according to the general principles of law adopted by the U.N.”
It goes without saying, that the Universal Declaration of Human Rights and the special International Covenant on Civil and Political Rights have an international nature and Iraq is committed to the provisions stated therein for the aforementioned reasons.
However, we see in international criminal law acts considered as international crimes having another aspect differing from what is stated in the interior law, this is because the nature of international law being a customary law (unwritten), while the principle of the crimes and legal penalties and what results therefrom, did not develop except under the light of the written law. And the outcome is that the principle disagrees with the custom law, thus pursuant to this principle, the act may become subject to punishment if the said principle is stipulated in the legislation, for it is based on the written law, and therefore it is impossible to apply this principle on the customary regulations. But this does not mean that this principle cannot be absolutely applied in international criminal law.
It is true that this law is originally a customary law (based on customs), but nonetheless, it can be applied in this law in a way that differs from the way it is applied in national laws. For it is difficult to imagine that international law includes previous provisions by which the crimes and penalties are determined similarly as they are determined in the domestic law, i.e. it is difficult to find legal specimen outlined in specified formulas in international criminal law because it differs from the interior law of the various countries from several aspects.
It is true that international criminal law and international humanitarian law have developed towards codification, and significant efforts were exerted in this direction; especially post-Geneva Conventions and the Convention on the Prevention and Punishment of the Crime of Genocide, and finally after sanctioning the basic system of the International Criminal Court (Rome Statute). However, the fact indicates till now, to a large extent, especially concerning crimes against humanity, that bestowing the nature of crimes upon acts which are international crimes is done in the same way as the setting rules of international law are generally formed.
Moreover, the definition of crimes in international law is not precise as the definition of crimes in the national laws of different countries.
For to know which actions are considered crimes in international criminal law, we should rely on international custom which is the fundamental source of international law, and so in light of this basis we can discover the nature of the action and criminalize it.
On the other hand, it may happen, especially in the recent decades, that the criminal property of the action in international criminal law is revealed in writing, and this is the case of crimes stipulated in treaties, especially those named the obligatory legislative treaties even to countries which did not sign or join said treaties, taking into consideration that the terms of these treaties are originally international customary regulations, for the conventions of the Hague and Geneva are but a group of customary regulations known before being finalized in written provisions.
The noticeable matter is that the conventional international law, in respect to international crimes and others, does not decide the rules of international law, for there are other international rules originating from the obligatory international law.
On the other hand the conventional international law decides only the legal regulations already found and decided by virtue of international custom.
As a consequence, for the consideration of some actions punished by international law, it is not enough to refer to international treaties and conventions, but we should rely at first on international customary law.
For there are many actions deriving its properties directly from international custom without the interference of international conventional law, and therefore they are international crimes despite the fact that they are not stipulated in a treaty or convention. Although before year 1958 there did not exist any treaty deciding its criminal property, the same goes to the violations committed against humanity are considered international crimes before international conventional law decided this property in London convention of 1945.
Here we may ask if the principle of crime and penalty legality connects firmly to legislation (written law). Does this mean that it is not applied in international law which is originally a custom law? and does this mean that the results of this principle as the non-retroactive criminal law, and adhering to the limited explanation, do not apply on the crimes of international nature?
This court believes that despite the fact that international law is originally a customary law and despite the fact that the principle of the Crimes and Penalties according to legal provisions is related firmly to legislation, however, the requirements of justice and prevention of injustice and guarantee of individual freedom all require the applying of said principle in the scope of international crimes.
Thus, how can we apply this principle in the scope of international crimes? We can apply it through verifying that the action or prevention forms an international crime not necessarily originating from international conventions and treaties, whereas most of these crimes originate from international custom. Therefore, we have to assure from the existence of an international legal custom regulation criminalizing this action or prevention as being considered an international crime, at the time of attributing the committing of a crime to a person, or its existence (legal regulation) in a general international convention (legislative) or a special international convention in which Iraq is a member.
Consequently, the principle of the crimes and penalties legality is also applied in international criminal law. In international law it is impermissible to punish but for actions given the nature of a crime by international law at the time of committing it. 
Iraq, Iraqi High Tribunal, Trial Chamber, Al-Dujail case, Judgment, 5 November 2006, Part I, pp. 36–40, based on a translation available at http://law.case.edu/saddamtrial/dujail/opinion.asp (last accessed on 1 April 2010).
Iraq
In its judgment in the Al-Anfal case in 2007, the Iraqi High Tribunal stated:
… no act or abstention of action is sentenced if no legal description is available. [The] French had adopted, after their revolution, the crimes and sentences legislative principle … [This] principle had been reinforced via [the] International Human Rights Declaration issued by the UN General Assembly, on 1948 September 10, becoming a pattern to be followed by all countries. Its final form showed up in Article [11/ 2], as follows: “No person must be convicted due to an act or abstention of action unless the following is considered a crime as per national or international law at the time of perpetration. As well, no sentence heavier than that supposed to be issued at the time of perpetration must be given”. This statement expresses the opinion … that no crime or sentence must be applied unless it was previously documented in a text which defines it clearly, at a date previous to that of perpetration. This means that to consider an act as penalized crime, it must be defined by law at a time previous to its perpetration …
All Iraqi constitutions, excluding the monarchy constitution of 1925, clearly declared this principle which is available in the last Iraqi Permanent Constitution of 2005 and valid Iraqi Penal Code No [111] for the year 1969. It is worth mentioning though that Baghdadi Penal Code did not include this principle.
The International Human Rights’ Declaration is highly important in adopting and defining crimes legitimacy principle and sentences, as well as the refusal of retroactivity in International Tribunal Law. The aim of such principles, as per this declaration, is not limited to what nations’ internal laws adopt in different states for the importance of the act being stipulated as a crime, and punishable in the national laws when they were committed. Rather, it stretches within the International Tribunal Law to include international crimes. The act or refrain must be considered as international crime sentenced as per International Tribunal Law, and at the time of its commitment, whether the origin of such incrimination or sentence is available in international agreements and accords or internationally agreed upon.
Our court acknowledges that what occurred in Universal Declaration of Human Rights is obligatory to all countries, at least those members in the U.N., and due to the fact that Iraq is one of its founders, which impose on it to abide by such laws without the necessity to be mentioned in internal legal texts. What confirms the advanced opinion is Article [15] of Special International Convention for Civil and Political Rights, issued following a U.N. Resolution No [2200 A] on 1966 Dec 16, valid starting 1976 March 23, and approved by Iraq in 1976. Article [15] of the aforementioned convention stated:
“1. No individual is charged for acts or refrains which were not considered as crimes at the time of implementation, as per national or international law. Also, it is not allowed to impose a sentence which is more severe than that applicable at the time of implementation. If, after the crime’s perpetration, a legal text had been issued stating new lighter sentences, convicts must get the benefit of such mitigation.
2. This Article does not include any point that breaches the trial or sentence of any individual, for an act or refrain which was considered as a crime at the time of implementation, as per general laws recognized by International Community”.
There is no doubt that both the International Human Rights’ Declaration and the Special International Convention for Political and Civil Rights are characterized by [an] international feature abiding all member countries in the United Nations, including Iraq, due to the aforementioned reasons.
Article [1] of the Iraqi Penal Code stipulated “no punishment over an act or refrain, unless based on a law which stipulates its incrimination at the time of occurrence, as no verdicts or precautionary measures must be signed unless laid down by law”. 
Iraq, Iraqi High Tribunal, Al-Anfal case, Judgment, 24 June 2007, pp. 26–29 and 117, based on a translation available at http://law.case.edu/grotian-moment-blog/anfal/opinion.asp (last accessed on 1 April 2010).
Pakistan
In its judgment in the Baluch case in 1968, the Supreme Court of Pakistan stated:
It is well-settled that a law is not to be given retrospective effect unless it is expressly or by necessary intendment made retrospective … In the present case, what was under challenge in the High Court, was the validity of the detention order passed on the 11th August 1966, which was made before the present amendments came into force. The validity of that order has, of necessity, therefore, to be judged on the basis of the law prevailing on that day. 
Pakistan, Supreme Court, Baluch case, Judgment, 24 May 1968.
Pakistan
In his Separate Opinion in the Shahida Faisal case before Pakistan’s Lahore High Court in 2000, Judge Mian Nazir Akhtar stated:
12. The Universal Declaration of Human Rights incorporates a provision against retrospectivity of a penal offence. Its Article 11 reads as under:–
“No one shall be held guilty of any penal offence on account of any act or omission which did not constitute a penal offence under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed.”
13. The question of retrospectivity of a penal offence came up for consideration before the Supreme Court of Pakistan in the case of Nabi Ahmad and another v. The Home Secretary, Government of West Pakistan, Lahore and 4 others (PLD 1969 SC 599). It was held that statutes are presumed to be applicable to cases and facts coming into existence after their enactment unless there be clear intention to give them retrospective effect. In this judgment it was clarified that the expression retrospective statute is relatable to a civil matter whereas the expression ex post facto legislation pertains to criminal matters. The Court referred to the nature and meaning of ex post facto law as follows: –
“An ex post facto law is one which makes criminal and punishes an act which was done before the passage of the law and which was innocent when done, aggravates a crime or makes it greater than it was when committed, changes the punishment and inflicts a greater punishment than was prescribed when the crime was committed, or, alters the legal rules of evidence and receives less or different testimony than was required to convict at the time the offence was committed. Further, an ex post facto law may be one which, assuming to regulate civil rights and remedies only, in effect imposes a penalty or the deprivation of a right for something which when done, was lawful, deprives persons accused of crime of some lawful protection or defence previously available to them, such as the protection of a former conviction or acquittal, or of a proclamation of amnesty, or generally, in relation to the offence or its consequences, alters the situation of an accused to his material disadvantage.” (Taken from Corpus Juris Secundum, Vol. 16-A, Article 435).
The Court was pleased to hold that: –
“Rights of the parties arising from facts which come into existence before the passing of a statute should be presumed to be unaffected by it unless it is expressly or by necessary implication made retrospective. The full significance, and implications, of the protection cannot be fully appreciated, unless we discover its reason. This is not a statutory protection, yet the principle has by virtue of a presumption of fair play effectively checked encroachments on existing rights by the all powerful British Parliament, unless they were found to have been clearly and unambiguously so intended. The origin of this presumption is to be found in the conscientious abhorrence that all just men have for the injustice that is inherent in changing the legal implications of a situation to the disadvantage of those who would otherwise benefit by a right which existed at the time of the change. As a manifestation of more or less, a natural or instinctive sense of justice, or perhaps gut instinctive repugnance to what one feels to be injustice, the Courts have held that laws do not ‘impose new liabilities in respect of events taking place before their commencement’. Since the above way of thinking is the consequence of a sense of aversion for injustice, it is immaterial ‘whether the law is changed before the hearing of the case at first instance or whilst an appeal is pending’. One more consideration which appeals is that law-abiding members of society regulate their lives according to the law as it exists at the time of their actions, and they expect the law to be steadfast and reliable. They assess and weigh the consequences according to the demands of existing system of law, including the requirements implicit in the existing system of law, and are entitled to feel cheated if the law later lets them down by taking away or reducing their rights, or increasing their burdens. The time at which a presumption arises against retrospectivity is to be determined by the circumstances which call for protection against injustice. The differences in the manifestations of this deed are mere matters of detail. The need may arise before the commencement of proceedings with reference to the time at which a cause of action arose, or an innocent deed was done. This happens if, for instances, a law is made to eliminate that cause of action or to make that innocent act punishable. It may also arise with reference to the time at which a new law was enforced during the pendency of a proceeding. Such an occasion can arise if, for instance, the right of appeal is abolished after the institution of a proceeding. So also it may arise with reference to the time at which a proceeding, whether civil or criminal was concluded by a decree, conviction or acquittal, and then a law was passed taking away the right of appeal against the decree, conviction or acquittal, when no proceeding was pending. When we think of such an injustice, we are really thinking of the adverse effect of the new law on vested rights.”
14. Justice Blackstone explained ex post facto laws in the case of Philips v. Eyre (1870) 6 QB 1 in the following words:–
“After an action, indifferent in itself, is committed, the Legislature then for the first time, declares it to have been a crime, and inflicts a punishment upon the person who has committed it. Here it is impossible, that the party could foresee that an action, innocent when it was done, should be afterwards converted to guilt by a subsequent law; he had therefore, no cause to abstain from it; and all punishment for not abstaining must of consequence be cruel and unjust”.
15. The prohibition against ex post facto legislation was contained in the 1956 and 1962 Constitutions of Pakistan. Article 6 of the 1956 Constitution of Pakistan containing prohibition against conviction for an offence which was not an offence when committed is materially the same as Article 20 of the Indian Constitution. However, Article 9 of 1962 Constitution is substantially the same as Article 12 of the Constitution of Pakistan, 1973 which reads as under:–
“Protection against retrospective punishment.–
(I) No law shall authorise the punishment of a person–
(a) for an act or omission that was not punishable by law at the time of the act or omission; or
(b) for an offence by a penalty greater than; or of a kind different from; the penalty prescribed by law for that offence at the time the offence was committed.”
The word “law” used in sub-clauses (a) and (b) of clause (1) of the above-quoted Article means law in operation at the time of the commission or omission charged as an offence. A law in force cannot be equated with a law “deemed to be in force” through ex post facto legislation. The term “law” used in the Article postulates actual and not notional existence of the law at the relevant time. 
Pakistan, Lahore High Court, Shahida Faisal case, Separate Opinion of Judge Mian Nazir Akhtar, 14 June 2000, §§ 12–15.
Peru
In 2004, in the Gabriel Orlando Vera Navarrete case, Peru’s Constitutional Court stated:
The lex praevia guarantee derived from the principle of legality is not violated in the case of a continuing crime if a criminal law is applied that was not in force before the point in time when the execution of the crime began but which has entered into force while the crime was being committed. Thus, the fact that the crime of enforced disappearances was not in force does not impede a criminal prosecution for this crime and the punishment of those responsible. 
Peru, Constitutional Court, Gabriel Orlando Vera Navarrete case, Case No. 2798-04-HC/TC, Judgment, 9 December 2004, § 22.
Peru
In 2006, in the Colegio de Abogados de Lima case, Peru’s Constitutional Court stated:
22. As such, the principle of legality ensures: a) the prohibition against retroactive application of criminal law (lex praevia); b) the prohibition of analogy (lex stricta); c) the prohibition of indeterminate legal provisions (lex certa); and d) the prohibition against the application of non-statutory law (lex scripta).
23. In conformity with its lex praevia component, the principle of legality prohibits the retroactive application of criminal law, except of course when its application benefits the accused.
25. … [T]he principle of legality requires not only that the crimes be defined by law, but also that the prohibited conduct be clearly delimited in the law. This is known as the certainty requirement, which prohibits the enactment of indeterminate criminal laws.
26. With regards to the lex scripta requirement, the principle of legality establishes that the accusation and punishment of criminal behaviour be based solely on statutory law, prohibiting, among other issues, basing punishment on customary law. 
Peru, Constitutional Court, Colegio de Abogados de Lima case, Case No. 0012-2006-HC/TC, Judgment, 15 December 2006, §§ 22–23 and 25–26.
Peru
In 2007, in the Chuschi case, the Permanent Criminal Chamber of Peru’s Supreme Court of Justice stated:
[I]n order to avoid breaching the constitutional rule of non-retroactive application of the law, the continuous act [of enforced disappearance] shall be punished under the law that defined the crime if the perpetrator commits the acts fully or partially after the law’s entry into force. The unlawful situation generated by the perpetrator, which encompasses the entire period until the consummation of the offence, must reach the new law’s date of entry into force. 
Peru, Supreme Court of Justice, Permanent Criminal Chamber, Chuschi case, Case No. 1598-2007, Judgment, 24 September 2007, pp. 161–162.
Peru
In 2007, in the Castillo Páez case, the First Provisional Criminal Chamber of Peru’s Supreme Court of Justice stated with regard to the offence of enforced disappearance:
[T]he events of this case occurred on 21 October 1990 (before the current Criminal Code, which contains the crime of enforced disappearance, entered into force). But since enforced disappearance is a continuous crime, it shall be interpreted to have been committed under the current Code and the provisions of this Code shall be considered applicable. Although in constitutional criminal matters the general rule of “lex praevia” applies (by which the norm must exist prior to the commission of the criminal act), the situation described above constitutes the continuous commission of an unlawful act, prolonged in time, and defined by the new law (given that the whereabouts of the victim continue to be unknown). In this sense, it is worth noting that if the accused have committed the unlawful act constituting the crime which is continuous covered by the new law in force, there is no doubt that the law is applicable with no retroactive effect ad malam partem. This has been the position of the Constitutional Court in the following cases: docket no. 2488-2002-HC/TC, the Genaro Villegas Namuche case (judgment of 18 March 2004, para. 26); docket no. 2529-2003-HC/TC, Peter Cruz Chávez case (judgment of 2 July 2004, para. 3); docket no. 467-2005-PHC/TC Juan Nolberto Rivero Lazo case (judgment of 12 August 2005, para. 25); docket no. 0442-2007-HC/TC, Collins Collantes Guerra case (judgment of 30 March 2007, para. 6). 
Peru, Supreme Court of Justice, First Provisional Criminal Chamber, Castillo Páez case, Case No. 0012-2006-HC/TC, Judgment, 18 December 2007, § 3(v).
United States of America
The Agent Orange case in 2005 involved a class action suit filed on behalf of various Vietnamese nationals and an organization, The Vietnamese Association for Victims of Agent Orange/Dioxin, against Dow Chemical and other US chemical manufacturers, for harms allegedly done to them and their land through the United States’ use of Agent Orange and other herbicides during the Vietnam War from 1965 to 1971 and by the South Vietnamese government’s subsequent use of such herbicides until 1975. In dismissing the claims, the Court found that, while recognizing the evolution of international law since 1975, the use of herbicides did not violate, at the time they were used, either customary or conventional international law binding on the United States. With regard to ex post facto liability the Court stated:
A party is not bound by a treaty prior to the date such a treaty enters into force for it; treaties are not retroactive. Vienna Convention on the Law of Treaties, May 23, 1969, art. 28, 1155 U.N.T.S. 331, 339 (entered into force Jan. 27, 1980) (“Unless a different intention appears from the treaty or is otherwise established, its provisions do not bind a party in relation to any act or fact which took place or any situation which ceased to exist before the date of the entry into force of the treaty with respect to that party.”); see also J. Mervyn Jones, The Retroactive Effect of the Ratification of Treaties, 29 AM. J. INT’L L. 51 (1935). The Vienna Convention on the Law of Treaties, albeit not ratified by the United States to date, is regarded as largely declaratory of existing law and has been recognized as such by the United States Department of State. LORI FISLER DAMROSCH, LOUIS HENKIN, RICHARD CRAWFORD PUGH, OSCAR SCHACHTER & HANS SMIT, INTERNATIONAL LAW CASES AND MATERIALS 452-54 (4th ed. 2001); see also DAVID J. BEDERMAN ET AL., INTERNATIONAL LAW: A HANDBOOK FOR JUDGES 18 (Am. Soc’y of Int’l Law 2003) (“[E]ven though the United States is not a party [to the Vienna Convention on the Law of Treaties], it regards almost all of the [Convention]’s provisions as binding customary international law.”). As Professor Anderson opined [Decl. of Kenneth Howard Anderson, Jr., Nov. 2, 2004]:
International law as a general proposition does not permit retroactive application … International law could hardly develop if states believed that by accepting newly developed norms of international law, the result would be to hold them liable under today’s norms for behavior acceptable under yesterday’s. This consideration has particular importance for the international law of war – a body of law in which all acts for which individuals might be held liable are criminal … a body of law in which the acts at issue are ones involving great death, destruction and violence. States, in the interests of protecting their soldiers, would not agree to new and more restrictive rules, including criminal liability, if they believed that it would subject them and their military personnel to ex post facto liability.
Anderson Decl. ¶ 35 (footnote moved to text). 
United States, Eastern States District Court (EDNY), Agent Orange case, Judgment, 28 March 2005, pp. 129–130.
United States of America
The Hamdan case in 2006 involved a Yemeni national in custody at the US naval base in Guantanamo Bay, Cuba, who petitioned for writs of habeas corpus and mandamus to challenge the Executive’s intended means of prosecuting a charge of conspiracy to commit offences triable by a military commission. In a majority opinion, the US Supreme Court found that the military commissions convened to try Hamdan violated in structure and procedure both the Uniform Code of Military Justice (UCMJ) and the 1949 Geneva Conventions. With regard to whether the crime of “conspiracy” is a recognized violation of the laws of war, Justice Stevens, joined by Justices Souter, Ginsberg and Breyer, held that:
[N]one of the major treaties governing the law of war identifies conspiracy as a violation thereof. And the only “conspiracy” crimes that have been recognized by international war crimes tribunals (whose jurisdiction often extends beyond war crimes proper to crimes against humanity and crimes against the peace) are conspiracy to commit genocide and common plan to wage aggressive war, which is a crime against the peace and requires for its commission actual participation in a “concrete plan to wage war.” 1 Trial of the Major War Criminals Before the International Military Tribunal: Nuremberg, 14 November 1945-1 October 1946, p 225 (1947). The International Military Tribunal at Nuremberg, over the prosecution’s objections, pointedly refused to recognize as a violation of the law of war conspiracy to commit war crimes, see, e.g., 22 id., at 469, and convicted only Hitler’s most senior associates of conspiracy to wage aggressive war, see S. Pomorski, Conspiracy and Criminal Organization, in the Nuremberg Trial and International Law 213, 233–235 (G. Ginsburgs & V. Kudriavtsev eds. 1990). As one prominent figure from the Nuremberg trials has explained, members of the Tribunal objected to recognition of conspiracy as a violation of the law of war on the ground that “[t]he Anglo-American concept of conspiracy was not part of European legal systems and arguably not an element of the internationally recognized laws of war.” T. Taylor, Anatomy of the Nuremberg Trials: A Personal Memoir 36 (1992); see also id., at 550 (observing that Francis Biddle, who as Attorney General prosecuted the defendants in Quirin, thought the French judge had made a “‘persuasive argument that conspiracy in the truest sense is not known to international law’”). 
United States, Supreme Court, Hamdan case, Judgment, Part V, 29 June 2006.
United States of America
In 2008, in the Khadr case, a Guantánamo Military Commission considered a Defence motion to dismiss Charge One for failure to state an offence and for lack of subject matter jurisdiction. In denying the Defence motion, the Commission firstly noted Charge One and its Specification:
CHARGE I: VIOLATION OF 10 U.S.C. §950v(b)(15), MURDER IN VIOLATION OF THE LAW OF WAR
Specification: In that Omar Ahmed Khadr, a person subject to trial by military commission as an alien unlawful enemy combatant, did, in Afghanistan, on or about July 27, 2002, while in the context of and associated with armed conflict and without enjoying combatant immunity, unlawfully and intentionally murder U.S. Army Sergeant First Class Christopher Speer, in violation of the law of war, by throwing a hand grenade at U.S. forces resulting in the death of Sergeant First Class Speer. 
United States, Guantánamo Military Commission, Khadr case, Ruling, 21 April 2008, § 2.
The Commission then stated the following regarding the ex post facto aspects of the Defence motion:
8. The defense asserts that the specific statutory provision in question, 10 U.S.C. Sec. 950v(b)(15), did not exist at the time of the offenses charged. Since the offenses charged allegedly occurred in 2002 and the statute in question was enacted in 2006, that assertion is beyond dispute. Assuming for the purposes of this paragraph of this motion that Mr. Khadr is entitled to specific, partial or limited protections of the Constitution, the commission will evaluate the provision in light of Ex Post Facto standards:
a. On its face, the provision applies to Mr. Khadr. The jurisdictional provisions of the MCA [Military Commissions Act 2006] (Section 948d) set forth that any person who may be tried by a military commission may be tried for any offense listed in the MCA – whether committed before, on, or after 11 September 2001.
b. The Supreme Court has recognized Congress’ authority in this area (See, eg., Ex Parte Quirin, 317 U.S. 1, 63 S.Ct. 2 (1942). It has stated that “An important incident to the conduct of war is the adoption of measures by the military command not only to repel and defeat the enemy, but to seize and subject to disciplinary measures those enemies who in their attempt to thwart or impede our military effort have violated the law of war.” Ex Parte Quirin, Id., at 10.
c. The Congressional decision to enact the murder in violation of the law of war provision was not a decision to create a new crime and Congress did not create a new crime. The Supreme Court recognized that Congress has and has had the choice of allowing military commissions to determine for themselves what are violations of the law of war or of setting out specifically certain violations of the law of war. “Congress had the choice of crystallizing in permanent form and in minute detail every offense against the law of war, or of adopting the system of common law applied by military tribunals so far as it should be recognized and deemed applicable by the courts … .” Ex Parte Quirin, Id., at 12.
d. The commission concludes that prosecution of Mr. Khadr for the offense of murder in violation of the law of war, as defined by the provision in question, does not violate ex post facto standards – whether under the Constitution or international law. 
United States, Guantánamo Military Commission, Khadr case, Ruling, 21 April 2008, § 8.
Algeria
In 2006, in its third periodic report to the Human Rights Committee, Algeria stated:
57. Since 1991, Algeria has had to confront terrorism in an atmosphere of indifference and suspicion. Efforts to combat this scourge, requiring the implementation of special measures, have always been deployed within the framework of the law and respect for human dignity.
58. In order to deal with this exceptional situation, in February 1992 the Algerian authorities decided to declare – as they are entitled to do under the Constitution – a state of emergency. Although the state of emergency did impose some restrictions on the exercise of civil rights and liberties, it did not relieve the State of its obligations to guarantee the right to exercise the fundamental civil liberties provided for in the existing domestic constitutional order and in the international agreements ratified by Algeria.
59. The exceptional measures taken during the state of emergency were all accompanied by guarantees for the protection of human rights. No restrictions were placed on the rights and freedoms enshrined in [inter alia, article 15] of the International Covenant on Civil and Political Rights. 
Algeria, Third periodic report to the Human Rights Committee, 7 November 2006, UN Doc. CCPR/C/DZA/3, submitted 22 September 2006, §§ 57–59.
Azerbaijan
In 2007, in its third periodic report to the Human Rights Committee, Azerbaijan stated:
Under the provisions of article 10 of the Criminal Code of the Republic of Azerbaijan, the criminality of a given act and the penalties which it incurs are determined by the criminal law in force at the time the act was committed. No one may be held criminally responsible for an act which was not recognized as an offence at the time of its perpetration. 
Azerbaijan, Third periodic report to the Human Rights Committee, 10 December 2007, UN Doc. CCPR/C/AZE/3, submitted 4 October 2007, § 413.
Bosnia and Herzegovina
In 2005, in its initial report to the Human Rights Committee, Bosnia and Herzegovina stated:
… [T]he Stability Pact [Stability Pact for South Eastern Europe, to which Bosnia and Herzegovina is a party] bans the retroactive implementation of a Criminal Code … [It requires] that the principle of non retroactivity be performed in the regular Criminal Code, both in peace and during war. No one can be found guilty for any actions or faults which were not considered to be criminal actions according to the local and international laws at the time when they were committed. 
Bosnia and Herzegovina, Initial report to the Human Rights Committee, 24 November 2005, UN Doc. CCPR/C/BIH/1, § 194.
Chad
In 1997, in its initial report to the Committee on the Rights of the Child, Chad stated: “In the criminal sphere, articles 22–25 of the Constitution specify that … [n]o one may be arrested or charged except by virtue of a law promulgated prior to the acts of which he is accused.” 
Chad, Initial report to the Committee on the Rights of the Child, 24 July 1997, UN Doc. CRC/C/3/Add.50, submitted 14 January 1997, § 91.
Croatia
In 2007, in its second periodic report to the Human Rights Committee, Croatia stated that its Constitution provides that “no one shall be punished for an act which before its commission was not defined as a punishable offence by law or international law, nor may he or she be sentenced to a penalty which was not defined by law”. 
Croatia, Second periodic report to the Human Rights Committee, 2 December 2008, UN Doc. CCPR/C/HRV/2, submitted 28 November 2007, § 317.
Democratic Republic of the Congo
In 2005, in its third periodic report to the Human Rights Committee, the Democratic Republic of the Congo stated:
56. Article 134, paragraphs 1 and 3, of the transitional Constitution provide that: “In accordance with the provisions of article 73 of the present Constitution, the President of the Republic declares war on a decision of the Council of Ministers on the recommendation of the National Defence Council and authorization of the National Assembly and Senate. The rights and duties of citizens in time of war or in the event of invasion or attack on the country by foreign forces shall be governed by an organization act.”
57. Although the Constitution does not explicitly state which rights may be derogated from, in the event of the proclamation of a state of war or emergency, by constitutional tradition there is no authorization for derogation from the following fundamental rights: the right to life, the right to physical integrity (right not to be tortured), the right to equality, the right not to be kept in slavery or servitude, the right not to be imprisoned for acts of commission or omission which did not constitute offences when they were perpetrated, freedom of thought, conscience and religion, and recognition of legal personality. 
Democratic Republic of the Congo, Third periodic report to the Human Rights Committee, UN Doc. CCPR/C/COD/2005/3, 3 May 2005, §§ 56–57.
Finland
In 2003, in its fifth periodic report to the Human Rights Committee, Finland stated:
230. The principle of legality in criminal law (nullum crimen sine lege) is provided for in section 8 of the Finnish Constitution, according to which no one shall be found guilty of a criminal offence or be sentenced to a punishment on the basis of a deed, which has not been determined punishable by an Act at the time of its commission. The penalty imposed for an offence shall not be more severe than that provided by an Act at the time of commission of the offence.
231. The corresponding obligations in Article 15 of the Covenant [1966 International Covenant on Civil and Political Rights] and in Article 7, paragraph 2, of the European Convention on Human Rights, respectively, are absolute. The reference to human rights conventions in section 23 of the Finnish Constitution means that derogation from the provisions of Article 15 is not possible, not even in exceptional situations.
232. In the spring of 2003, in connection with the reform of the Penal Code, specific provisions on the principle of legality and temporal restrictions as to the application of the penal provisions, were added to the Penal Code. The new provisions are scheduled to enter into force at the beginning of 2004. According to the new provisions in section 1 of Chapter 3 of the Penal Code, no one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence at the time of its commission. The sentence or any other criminal law sanction must be based on law. New section 2 in the same Chapter concerns the temporal restrictions, providing, inter alia, for the principle of the lighter penalty referred to in Article 15. However, the relevant bills (HE 44/2002) passed already by Parliament are still waiting for approval of the President of the Republic. 
Finland, Fifth periodic report to the Human Rights Committee, 24 July 2003, UN Doc. CCPR/C/FIN/2003/5, submitted 17 June 2003, §§ 230–232.
Finland
In 2006, in a report to the Counter-Terrorism Committee of the UN Security Council, Finland stated: “According to the Constitution of Finland, no one shall be found guilty of a criminal offence or be sentenced to a punishment on the basis of a deed which has not been determined punishable by an Act at the time of its commission.” 
Finland, Report to the Counter-Terrorism Committee of the Security Council in response to its questions on Finland’s implementation of the provisions of resolution 1624(2005) presented in its letter of 15 May 2006, enclosure to Letter dated 14 July 2006 from the permanent representative of Finland to the United Nations addressed to the Chairman of the Counter-Terrorism Committee, annexed to UN Doc. S/2006/506, 19 July 2006, Letter dated 17 July 2006 from the Chairman of the Security Council Committee established pursuant to resolution 1373 (2001) concerning counter-terrorism addressed to the President of the Security Council, p. 7.
Hungary
In 2004, in its second periodic report to the Committee on the Rights of the Child, Hungary stated: “Pursuant to the Criminal Procedures Act, the principle of nullum crimen sine lege is a guaranteed rule.” 
Hungary, Second periodic report to the Committee on the Rights of the Child, 24 May 2005, UN Doc. CRC/C/70/Add.25, submitted 17 February 2004, § 508.
Jordan
The Report on the Practice of Jordan states that Article 75 of the 1977 Additional Protocol I embodies customary law. 
Report on the Practice of Jordan, 1997, Chapter 5.
Morocco
In 2004, in its fifth periodic report to the Human Rights Committee, Morocco stated:
196. Article 10 of the Constitution establishes the principle of the legality of offences and penalties: “No person may be arrested, detained or punished except under the conditions and in the manner prescribed by law.”
197. The principle of the legality of offences and penalties is reiterated in the Criminal Code, which establishes the principle of non-retroactivity of the law. 
Morocco, Fifth periodic report to the Human Rights Committee, 11 May 2004, UN Doc. CCPR/C/MAR/2004/5, submitted 10 March 2004, §§ 196–197.
Morocco
In 2005, in response to the concluding observations of the Human Rights Committee, Morocco stated:
Article 4 of the Criminal Code stipulates as follows: “No one shall be held guilty of an offence on account of an act that did not constitute a criminal offence under the law in force at the time it was committed”. The Moroccan Constitution recognizes the same principle; article 4 provides: “The law shall be the supreme expression of the will of the nation. Everyone shall comply with the law, which shall not have retroactive effect”.  
Morocco, Comments by the Government of Morocco on the Concluding Observations of the Human Rights Committee, January 2005, UN Doc. CCPR/CO/82/MAR/Add.1, 28 February 2005, pp. 4–5.
Nepal
In 2004, in a declaration of commitment on the implementation of human rights and international humanitarian law, the Prime Minister of Nepal stated:
No person shall be prosecuted and punished more than once for the same offence. For the dispensation of justice, only the competent court complying with all judicial proceedings shall have the right to pronounce the verdict in accordance with law. 
Nepal, Declaration of commitment on the implementation of human rights and international humanitarian law, 26 March 2004, § 11.
Oman
In 2005, in its second periodic report to the Committee on the Rights of the Child, Oman stated:
We affirm that this principle is in effect, it being one of the fundaments of the penal legislation in the Sultanate, as stipulated in article 21 of the Basic Law of the State, which prescribes that there shall be no punishment except for acts subsequent to the entry into force of the law providing for those acts. 
Oman, Second periodic report to the Committee on the Rights of the Child, 8 May 2006, UN Doc. CRC/C/OMN/2, submitted 28 April 2005, § 456.
Pakistan
In 2001, in its second periodic report to the Committee on the Rights of the Child, Pakistan stated the following principle from its Constitution: “Penal sanctions shall not be applied without prior legislation, and penal laws shall not be applied retrospectively (art. 12).” 
Pakistan, Second periodic report to the Committee on the Rights of the Child, 11 April 2003, UN Doc. CRC/C/65/Add.21, submitted 19 January 2001, § 366.
Poland
In 2004, in its fifth periodic report to the Human Rights Committee, Poland stated:
In the judgement of 26 July 1991 the Supreme Court indicated that standards of a democratic state of law require that the principle nullum crimen sine lege, arising from article 15 of the [1966 International Covenant on Civil and Political Rights (ICCPR)], should be used in all penal measures (not only in those of criminal law). At present it is one of the constitutional guarantees, according to which “Penal liability shall be incurred only by a person who commits an act prohibited under penalty, by a law in force at the time of its commission”. This principle is likewise contained in article 1 § 1 of the Penal Code. The Constitution specifies that, analogously to article 15.2 of the ICCPR, the above principle does not preclude penalisation for an act which at the time of its commission constituted an offence under international law. It is also guaranteed that war crimes and crimes against humanity are non-prescriptible. A provision to this effect was furthermore contained in the Law on the National Remembrance Institute – Commission for the Prosecution of Crimes Against the Polish Nation. Prosecution of Communist crimes perpetrated in Poland in the period 1944–1989 on the strength of this law takes place with the observance of the principle lex retro non agit in the sense that currently prosecuted are only those acts of functionaries of the Communist state which constituted offences under the criminal law in force at the time of their commission. 
Poland, Fifth periodic report to the Human Rights Committee, UN Doc. CCPR/C/POL/2004/5, 26 January 2004, § 296.
Senegal
In 2011, in its third periodic report to the Committee against Torture, Senegal stated:
Article 2 of the [1984] Convention [against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment
93. New legislative measures have been adopted to strengthen the law in this respect:
- Act No. 2007-02 of 12 February 2007 incorporated articles 431-1, 431-2, 431-3, 431-4 and 431-5 into the [1965 Penal] Code [as amended in 1999]. These articles deal with the crime of genocide, crimes against humanity, war crimes and other crimes under international law, such as those covered by the Hague Conventions of 1954, 1976 and 1980, which had not previously been specified in the Code.
- Article 431-6 of the [Penal] Code stipulates that perpetrators of the violations covered by articles 431-1 to 431-5, the provisions of article 4 of the Code notwithstanding, may be tried and sentenced for an act or an omission which, at the time and in the place of its commission, constituted a criminal offence according to the general principles of law recognized by the community of nations, regardless of whether or not it constituted a crime under the law in force at that time and place. 
Senegal, Third periodic report to the Committee against Torture, 5 October 2011, UN Doc. CAT/C/SEN/3, submitted 9 February 2011, § 93; see also §§ 271–272.
Serbia and Montenegro
In 2003, in its initial report to the Human Rights Committee, Serbia and Montenegro stated:
151. According to Article 99, paragraph 11, of the Constitution of the Federal Republic of Yugoslavia, enactments adopted during a state of war may throughout the duration of the state of war restrict various rights and freedoms of man and the citizen, except specific rights and freedoms guaranteed by the Constitution (… protection from punishment for an act which did not constitute a criminal offence under the law at the time of commission …
153. Pursuant to the Charter of Human and Minority Rights and Civil Liberties [of the State Union of Serbia and Montenegro, adopted in 2003], derogation from human and minority rights guaranteed by this Charter is allowed following the declaration of a state of war or a state of emergency, if the existence of the State Union or a member State is threatened, but only to the extent necessary under the given circumstances. Measures of derogation from human and minority rights cease to have effect following the end of the state of war or the state of emergency. No derogation is permitted even during the state of war or the state of emergency from the … right to a fair trial; … ban on retroactivity. 
Serbia and Montenegro, Initial report to the Human Rights Committee, UN Doc. CCPR/C/SEMO/2003/1, 24 July 2003, §§ 151 and 153.
Serbia and Montenegro
In its oral pleadings before the ICJ in the Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro) in 2006, Serbia and Montenegro stated:
The rules of criminal procedure in all countries demand a strict interpretation of the relevant texts, according to the old maxim nullum crimen sine lege, nulla poena sine lege (no crime can be committed and no punishment can be imposed without an existing law). The fact that international criminal law is to be interpreted strictly is borne out by Article 22.2 of the recent Statute of the International Criminal Court, which stipulates that “[t]he definition of a crime shall be strictly construed and shall not be extended by analogy. In case of ambiguity, the definition shall be interpreted in favour of the person being investigated, prosecuted or convicted.” 
Serbia and Montenegro, Oral pleadings before the ICJ, Application of the Convention on the Prevention and Punishment of the Crime of Genocide case (Bosnia and Herzegovina v. Serbia and Montenegro), 14 March 2006, Verbatim Record CR 2006/18, p. 21, § 41.
Somalia
In 2011, in its report to the Human Rights Council, Somalia stated:
Somalia has not ratified AP II [1977 Additional Protocol II] and it is therefore not directly applicable to Somalia as a matter of treaty law. The Government is aware that many provisions of AP II represent customary IHL rules and therefore apply to the situation in Somalia. Such provisions include … Article 6 providing the rule on penal prosecutions due to the fact that these norms are reflected in Common Article 3 of the [1949] Geneva Conventions. 
Somalia, Report to the Human Rights Council, 11 April 2011, UN Doc. A/HRC/WG.6/11/SOM/1, § 75.
Switzerland
In 2010, in its Report on IHL and Current Armed Conflicts, Switzerland’s Federal Council stated:
3.4 [Increasing use] of anti-guerrilla tactics
Apart from the direct fight against insurgents, international humanitarian law also addresses other anti-guerrilla tactics. … If members of militias or opposition groups fall into the hands of the government they benefit from the protection of art. 75 of [the 1977] Additional Protocol I as well as that of art. 3 common to the [1949] Geneva Conventions. 
Switzerland, Federal Council, Report on IHL and Current Armed Conflicts, 17 September 2010, Section 3.4, p. 15.
[footnotes in original omitted]
Syrian Arab Republic
The Report on the Practice of the Syrian Arab Republic asserts that the Syrian Arab Republic considers Article 75 of the 1977 Additional Protocol I to be part of customary international law. 
Report on the Practice of the Syrian Arab Republic, 1997, Chapter 5.1.
Syrian Arab Republic
In 2004, in its third periodic report to the Human Rights Committee, the Syrian Arab Republic stated:
61. The State of Emergency Act, which was promulgated in Legislative Decree No. 51 of 22 December 1962, as amended by Legislative Decree No. 1 of 9 March 1963, and which is currently in force in the Syrian Arab Republic, is an exceptional constitutional regime, based on the concept of an imminent threat to the country’s integrity, under which the competent authorities are empowered to take all the measures provided by law to protect the territory territorial waters and air space of the State, in whole or in part, from the dangers arising from external armed aggression by transferring some of the powers of the civil authorities to the military authorities. Article 101 of the Constitution states that the President of the Republic can declare and terminate a state of emergency in the manner stated in the law. Article 1 of this Act specifies the reasons justifying its promulgation by stipulating that a state of emergency can be proclaimed in the event of war, a situation entailing the threat of war or a situation in which security or public order in the territory of the Republic, or any part thereof, is jeopardized by internal disturbances or the occurrence of general disasters.
62. Since 1948, the Syrian Arab Republic, which was a founding member of the United Nations, has been subjected, like other neighbouring Arab States, to a real threat of war by Israel and, on many occasions, this threat of war has culminated in actual aggression against the territory, territorial waters and air space of the Syrian Arab Republic, particularly in 1967 when Israel seized part of the territory of the Syrian Arab Republic, which it is still occupying, and expelled a large proportion of its population. The latest incident of Israeli aggressions was in Ein El-Saheb on 5 October 2003.
63. This state of affairs, consisting in a real threat of war, the continued occupation of part of the territory of the Syrian Arab Republic and the existence of a real threat of seizure and ongoing occupation of further land in violation of United Nations resolutions, gave rise to an exceptional situation that necessitated the rapid and extraordinary mobilization of forces in the Syrian Arab Republic and, consequently, the promulgation of legislation to ensure the Administration’s ability to act rapidly in the face of these imminent threats when application of the ordinary legislation cannot guarantee rapid action in such circumstances. Accordingly, there was a need to promulgate this Act and maintain it in force. It should be borne in mind that all countries of the world have applied exceptional legislation, in one form or another, when they were faced with a state of war or a threat of war in order to protect their national security. This is a fundamental right recognized in the International Covenant on Civil and Political Rights, article 4 of which stipulates that: “In time of public emergency which threatens the life of the nation and the existence of which is officially proclaimed, the States Parties to the present Covenant may take measures derogating from their obligations under the present Covenant to the extent strictly required by the exigencies of the situation”.
68. The application of the provisions of the Emergency Act in Syria does not mean in any way a suspension of the provisions of the Constitution and other laws nor a derogation from other international obligations, including obligations in which Syria has entered by virtue of bilateral or multilateral international agreements, such as provisions of the International Covenant on Civil and Political Rights and the obligation to submit reports under article 40 of the Covenant. Furthermore, the grounds for a declaration of a state of emergency do not involve any discrimination on grounds of race, colour, gender, language, religion or social origin. The declaration of the state of emergency has not led to any violations of inter alia, article 15 of the International Covenant on Civil and Political Rights] which remain[s] enforceable under the Constitution and laws, in conformity with the Covenant. 
Syrian Arab Republic, Third periodic report to the Human Rights Committee, 19 October 2004, UN Doc. CCPR/C/SYR/2004/3, submitted 5 July 2004, §§ 61–63 and 68.
Uganda
In 2003, in its initial report to the Human Rights Committee, Uganda stated:
410. The principle of non-retroactive jurisdiction is contained in Uganda’s domestic legislation. Under Article 28 (7) of the Constitution “No person shall be charged with or convicted of a criminal offence which is founded on an act or omission that did not at the time it took place constitute a criminal offence”. The constitution also in a related manner prohibits “double jeopardy”, Article 28 (9) states that “A person who shows that he or she has been tried by a competent court for criminal offence and convicted or acquitted of that offence, shall not again be tried for the offence or for any criminal offence of which he or she could have been convicted at the trial for that offence, except upon the order of superior court in the course of appeal or review proceedings relating to the conviction or acquittal”.
411. Furthermore, article 28(10) prohibits trying a person for a criminal offence in which he has previously been pardoned. It states “No person shall be tried for a criminal offence if the person shows that he or she has been pardoned in respect of that offence”. There has not been a case since 1986 where the principle of non-retroactive jurisdiction has been violated. Even if it was, it would have been challenged under the law and under the independent judiciary in the country. 
Uganda, Initial report to the Human Rights Committee, 25 February 2003, UN Doc. CCPR/C/UGA/2003/1, submitted 14 February 2003, §§ 410–411.
United States of America
According to the Report on US Practice, “Articles 4, 5 and 6 [of the 1977 Additional Protocol II] reflect general US policy on treatment of persons in the power of an adverse party in armed conflicts governed by common Article 3” of the 1949 Geneva Conventions. The report also notes: “It is the opinio juris of the US that persons detained in connection with an internal armed conflict are entitled to humane treatment as specified in Articles 4, 5 and 6 [of the 1977 Additional Protocol II].” According to the report, it is also the opinio juris of the United States that military necessity will not justify derogation of the right not to be subjected to retroactive penal legislation. 
Report on US Practice, 1997, Chapter 5.3 and 5.7.
No data.
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International Criminal Court
In the Lubanga case before the ICC in 2006, Thomas Lubanga Dyilo, a former president of the Union des Patriotes Congolais (UPC) and commander-in-chief of the Forces patriotiques pour la libération du Congo (FPLC), was charged, inter alia, with the war crimes of enlisting, conscripting and using children under the age of 15 years to participate actively in hostilities, punishable under Article 8(2)(b)(xxvi) and (e)(vii) of the 1998 ICC Statute. 
ICC, Lubanga case, Warrant of Arrest, 10 February 2006.
In its Decision on the Confirmation of Charges in 2007, the Pre-Trial Chamber stated in relation to the consistency of these terms with the principle of legality:
302. Having regard to the principle of legality, the terms enlisting, conscripting and using children under the age of fifteen years to participate actively in hostilities are defined with sufficient particularity in articles 8(2)(b)(xxvi) and 8(2)(e)(vii), 22 to 24 and 77 of the Rome Statute and the Elements of Crimes, which entered into force on 1 July 2002, as entailing criminal responsibility and punishable as criminal offences.
303. Accordingly, there is no infringement of the principle of legality if the Chamber exercises its power to decide whether Thomas Lubanga Dyilo ought to be committed for trial on the basis of written (lex scripta) pre-existing criminal norms approved by the State Parties to the Rome Statute (lex praevia), defining prohibited conduct and setting out the related sentence (lex certa), which cannot be interpreted by analogy in malam partem (lex stricta). 
ICC, Lubanga case, Decision on the Confirmation of Charges, 29 January 2007, §§ 302–303.
International Criminal Tribunal for Rwanda
In its judgment in the Imanishimwe case in 2006, the ICTR Appeals Chamber commented on the consistency of its approach in interpretation with the principle of nullum crimen sine lege:
The Appeals Chamber recalls that the principle of legality, or the nullum crimen sine lege doctrine, does not prevent a court from determining an issue through a process of interpretation and clarification of the applicable law; nor does it prevent a court from relying on previous decisions which reflect an interpretation as to the meaning to be ascribed to particular provisions. The Appeals Chamber wishes to clarify that when it interprets certain provisions of the [1994 ICTR] Statute or the Rules [of Procedure and Evidence], it is merely identifying what the proper interpretation of that provision has always been, even though it was not previously expressed that way. 
ICTR, Imanishimwe case, Judgment on Appeal, 7 July 2006, § 127.
International Criminal Tribunal for the former Yugoslavia
In the Galić case before the ICTY in 1999, the accused, a senior officer in the Army of the Republika Srpska (VRS), was charged, inter alia, with “unlawfully inflicting terror upon civilians as set forth in Article 51 of Additional Protocol I and Article 13 of Additional Protocol II to the Geneva Conventions of 1949”, punishable under Article 3 of the 1993 ICTY Statute, as a violation of the laws or customs of war, for his alleged role in events in Sarajevo in 1992–1994. 
ICTY, Galić case, Indictment, 26 March 1999, Count 1.
In its judgment in 2003, the ICTY Trial Chamber, in its analysis of “acts of violence the primary purpose of which is to spread terror among the civilian population” as a violation of the laws or customs of war, stated:
92. The Majority also acknowledges the importance of the principle found in Article 15 of the 1966 International Covenant on Civil and Political Rights, which states, in relevant part: “No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. […] Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognised by the community of nations.”
93. The principle (known as nullum crimen sine lege) is meant to prevent the prosecution and punishment of a person for acts which were reasonably, and with knowledge of the laws in force, believed by that person not to be criminal at the time of their commission. In practice this means “that penal statutes must be strictly construed” and that the “paramount duty of the judicial interpreter [is] to read into the language of the legislature, honestly and faithfully, its plain and rational meaning and to promote its object.” Moreover:
The effect of strict construction of the provisions of a criminal statute is that where an equivocal word or ambiguous sentence leaves a reasonable doubt of its meaning which the canons of construction fail to solve, the benefit of the doubt should be given to the subject and against the legislature which has failed to explain itself. 
ICTY, Galić case, Judgment, 5 December 2003, §§ 92–93.
By majority decision, the Trial Chamber convicted the accused, inter alia, of “acts of violence the primary purpose of which is to spread terror among the civilian population” as a violation of the laws or customs of war. The accused was sentenced to 20 years’ imprisonment. 
ICTY, Galić case, Judgment, 5 December 2003, §§ 752 and 769, VI. Disposition.
In its judgment in 2006, the Appeals Chamber, by majority decision, upheld the Trial Chamber’s verdict, but quashed the sentence of 20 years’ imprisonment and imposed a sentence of life imprisonment. 
ICTY, Galić case, Judgment on Appeal, 30 November 2006, XVIII. Disposition, p. 185.
International Criminal Tribunal for the former Yugoslavia
In its judgment in the Stakić case in 2003, the ICTY Trial Chamber discussed the meaning of forcible transfer as an “other inhumane act”, a crime against humanity under the 1993 ICTY Statute:
719. The Trial Chamber recalls that “[t]he use of ‘other inhumane acts’ as a crime against humanity under Article 5(i) of the [1993 ICTY] Statute to attach criminal liability to forcible transfers, which are not otherwise punishable as deportations, raises serious concerns.” While noting that “[n]ot every law can be defined with ultimate precision and that it is for the jurisprudence to interpret and apply legal provisions which need, in part, to be formulated in the abstract”, the Trial Chamber declared that the description of a criminal offence extends beyond the permissible when the specific form of conduct prohibited can not be identified.” The Trial Chamber therefore held that as “[t]he crime of ‘other inhumane acts’ subsumes a potentially broad range of criminal behaviour and may well be considered to lack sufficient clarity, precision and definiteness” it might violate the fundamental criminal law principle nullum crimen sine lege certa.
720. This legal issue was addressed in Kupreškić, where the Trial Chamber held that the category “other inhumane acts” was:
deliberately designed as a residual category, as it was felt undesirable for this category to be exhaustively enumerated. An exhaustive categorization would merely create opportunities for evasion of the letter of the prohibition.
After referring to several international human rights instruments such as the Universal Declaration of Human Rights of 1948 and the two United Nations Covenants of 1966, the Kupreškić Trial Chamber concluded that by referring to such instruments one would be able to identify “less broad parameters for the interpretation of ‘other inhumane acts’” and “identify a set of basic rights appertaining to human beings, the infringement of which may amount, depending on the accompanying circumstances, to a crime against humanity.”
721. This Trial Chamber disagrees with that approach and notes that the international human rights instruments referred to by the Kupreškić Trial Chamber provide somewhat different formulations and definitions of human rights. However, regardless of the status of the enumerated instruments under customary international law, the rights contained therein do not necessarily amount to norms recognised by international criminal law. The Trial Chamber recalls the report of the Secretary-General according to which “the application of the principle nullum crime sine lege requires that the international tribunal should apply rules of international humanitarian law which are beyond doubt part of customary law.” Accordingly, this Trial Chamber hesitates to use such human rights instruments automatically as a basis for a norm of criminal law, such as the one set out in Article 5(i) of the Statute. Its hesitation is even more pronounced when, as in the present case, there is no need to undertake such an exercise. A norm of criminal law must always provide a Trial Chamber with an appropriate yardstick to gauge alleged criminal conduct for the purposes of Article 5(i) so that individuals will know what is permissible behaviour and what is not.
722. This Trial Chamber is not persuaded by the Prosecution’s argument that there are certain limited circumstances when the principle of certainty does not require specification of a prohibited conduct. For the present case, the Statute already provides a means to address illegal population transfers as the crime against humanity of deportation. Thus, from the point of view of consistent interpretation of the law, it is preferable to adopt the contextually correct definition of deportation. 
ICTY, Stakić case, Judgment, 31 July 2003, §§ 719–722.
[emphasis in original]
In contrast, in its judgment in 2006, the ICTY Appeals Chamber held:
The Appeals Chamber notes … that the notion of “other inhumane acts” contained in Article 5(i) of the [1993 ICTY] Statute cannot be regarded as a violation of the principle of nullum crimen sine lege as it forms part of customary international law. The function of this provision as a residual category is clear, as spelled out by the Trial Chamber in the Kupreškić Trial Judgement [quoted above by the Trial Chamber]. 
ICTY, Stakić case, Judgment on Appeal, 22 March 2006, § 315.
International Criminal Tribunal for the former Yugoslavia
In the Hadžihasanović case before the ICTY in 2003, the accused, senior officers in the Army of Bosnia and Herzegovina (ABiH), were charged with several counts of violations of the laws or customs of war for their alleged omissions as commanders in relation to acts allegedly committed by ABiH forces under their command and effective control in central Bosnia in 1993–1994. With regard to the question whether international law, at the relevant time, provided for criminal responsibility of superiors in the context of non-international armed conflicts, the Trial Chamber, in its 2002 Decision on Joint Challenge to Jurisdiction, held:
This Trial Chamber understands the principle of nullum crimen sine lege, a constitutive element of the principle of legality, in relation to the factual criminality of a particular conduct. In interpreting the principle of nullum crimen sine lege, it is critical to determine whether the underlying conduct at the time of its commission was punishable. The emphasis on conduct, rather than on the specific description of the offence in substantive criminal law, is of primary relevance. This interpretation of the principle is supported by the subsequent declaratory formulation of the principle of nullum crimen sine lege in Article 22 of the ICC Statute:
A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court.
This interpretation is further supported by the relevant practice between States in the field of extradition. In order to determine whether the requirement of double criminality is fulfilled, the test to be applied is not so much whether a certain conduct is qualified in the respective national jurisdiction in the same way, but whether the conduct in itself is criminalised under those jurisdictions. The Trial Chamber is fully aware of the different contexts in which these two principles are applied. However, the Trial Chamber observes the similarity of the underlying problem and legal guarantee. In order to meet the principle of nullum crimen sine lege, it must only be foreseeable and accessible to a possible perpetrator that his concrete conduct was punishable at the time of commission. Whether his conduct was punishable as an act or an omission, or whether the conduct may lead to criminal responsibility, disciplinary responsibility or other sanctions is not of material importance. 
ICTY, Hadžihasanović case, Decision on Joint Challenge to Jurisdiction, 12 November 2002, § 62.
[emphasis in original]
In its 2003 Decision on Interlocutory Appeal Challenging Jurisdiction in Relation to Command Responsibility, the ICTY Appeals Chamber agreed with the Trial Chamber’s findings and stated:
34. The Appellants argued … that the principle of legality requires that the crime charged be set out in a law that is accessible and that it be foreseeable that the conduct in question may be criminally sanctioned at the time when the crime was allegedly committed. The Appeals Chamber agrees with the answers given by the Trial Chamber. As to foreseeability, the conduct in question is the concrete conduct of the accused; he must be able to appreciate that the conduct is criminal in the sense generally understood, without reference to any specific provision. As to accessibility, in the case of an international tribunal such as this, accessibility does not exclude reliance being placed on a law which is based on custom. The Tadic Jurisdiction Decision shows that individual criminal responsibility can attach to a breach of a customary prohibition of certain conduct.
35. The Appellants further argue that the principle of legality requires the existence of a conventional as well as customary basis for an incrimination. The Appeals Chamber also agrees with the Trial Chamber’s rejection of this argument. The obligation of the Tribunal to rely on customary international law excludes any necessity to cite conventional law where customary international law is relied on. 
ICTY, Hadžihasanović case, Decision on Interlocutory Appeal Challenging Jurisdiction in Relation to Command Responsibility, 16 July 2003, §§ 34–35.
International Criminal Tribunal for the former Yugoslavia
In the Beqa Beqai case before the ICTY in 2004, the accused was charged with several counts of “contempt of the Tribunal”, on the basis of the ICTY’s “inherent power” and Rule 77 of its Rules of Procedure and Evidence. Allegedly, he had interfered with witnesses or potential witnesses in the case of the Prosecutor v. Fatmir Limaj, Haradin Bala and Isak Musliu (Case No. IT-03-66-T). 
ICTY, Beqa Beqai case, Amended Indictment, 8 November 2004, Counts 1–3.
In its judgment in 2005, responding to the “Defence’s argument that the Accused did not know about the specifics of the offence of contempt of court in the Tribunal’s Rules”, the Trial Chamber endorsed a statement by the Appeals Chamber in the Kordić and Čerkez case, according to which “‘the nullum crimen sine lege principle does not require that an accused knew the specific legal definition of each element of a crime he committed’”. (emphasis in original) It further agreed with the Prosecution’s argument “that ignorance of the law cannot be pleaded”, and found that the accused’s “awareness of the prohibition to interfere with witnesses is confirmed by his supposed knowledge of the rules on contempt of court in Kosovo”. 
ICTY, Beqa Beqai case, Judgment on Contempt Allegations, 27 May 2005, § 14.
The accused was found guilty of one count of contempt. 
ICTY, Beqa Beqai case, Judgment on Contempt Allegations, 27 May 2005, Part. VII (Disposition).
Special Court for Sierra Leone
In the Norman case before the SCSL in 2004, the accused, a senior member of the Civil Defence Forces (CDF), was charged, inter alia, with the use of child soldiers as an other serious violation of international humanitarian law, punishable under Article 4(c) of the 2002 Statute of the Special Court for Sierra Leone. 
SCSL, Norman case, Indictment, 4 February 2004, § 29, Count 8.
In its Decision on Preliminary Motion Based on Lack of Jurisdiction (Child Recruitment), the Appeals Chamber stated in relation to the principle of legality:
It is the duty of this Chamber to ensure that the principle of non-retroactivity is not breached. As essential elements of all legal systems, the fundamental principle nullum crimen sine lege and the ancient principle nullum crimen sine poena, need to be considered. In the ICTY case of Prosecutor v Hadžihasanović, it was observed that “In interpreting the principle of nullum crimen sine lege, it is critical to determine whether the underlying conduct at the time of its commission was punishable. The emphasis on conduct, rather than on the specific description of the offence in substantive criminal law, is of primary relevance.” In other words it must be “foreseeable and accessible to a possible perpetrator that his concrete conduct was punishable”. 
SCSL, Norman case, Decision on Preliminary Motion Based on Lack of Jurisdiction (Child Recruitment), Appeals Chamber, 31 May 2004, § 25.
In his Dissenting Opinion, Justice Robertson commented on the absolute nature of the principle of legality and stated:
11. … What restrains judges from creating new crimes is the overriding principle of legality, expressed invariably in Latin, nullum crimen sine lege – conduct, however awful, is not unlawful unless there is a criminal law against it in force at the time it was committed. As Article 15 of the International Covenant on Civil and Political Rights puts it,
No-one shall be held guilty of any criminal offence on account of any act or commission which did not constitute a criminal offence, under national or international law, at the time when it was committed.
13. The principle of legality, sometimes expressed as the rule against retroactivity, requires that the defendant must at the time of committing the acts alleged to amount to a crime have been in a position to know, or at least readily to establish, that those acts may entail penal consequences. Ignorance of the law is no defence, so long as that law is capable of reasonable ascertainment … In every case, the question is whether the defendant, at the time of conduct which was not clearly outlawed by national law in the place of its commission, could have ascertained through competent legal advice that it was contrary to international criminal law.
14. … There are some European Court of Human Rights decisions which suggest that the rule is primarily a safe-guard against arbitrary conduct by government. But it is much more than that. It is the very basis of the rule of law, because it impels governments (in the case of national law) and the international community (in the case of international criminal law) to take positive action against abhorrent behaviour, or else that behaviour will go unpunished. It thus provides the rationale for legislation and for treaties and Conventions – i.e. for a system of justice rather than an administrative elimination of wrongdoers by command of those in power. It is the reason why we are ruled by law and not by police.
15. Professor Cassesse explains in his textbook on International Criminal Law how the nulla crimen doctrine of strict legality, originating in Article 39 of Magna Carta has replaced the “substantive justice” doctrine initially adopted by international law. He poses the question:
A logical and necessary corollary of the doctrine of strict legality is that criminal rules may not cover acts or conduct undertaken prior to the adoption of such rules. Otherwise executive power, or the judiciary, could arbitrarily punish persons for actions that were legally allowed when they were carried out. By contrast, the ineluctable corollary of the doctrine of substantive justice is that, for the purpose of defending society against new and unexpected forms of criminality, one may go so far as to prosecute and punish conduct that was legal when taken. These two approaches lead to contrary conclusions. The question is: which approach has been adopted in international law?
The question must be answered firmly in favour of the doctrine of strict legality. A general rule prohibiting the retroactive application of criminal law has evolved after being laid down repeatedly in human rights treaties: see for example Article 7 of the European Convention of Human Rights; Article 15 of the UN Covenant on Civil and Political Rights; Article 9 of the Inter-American Convention on Human Rights and Article 7(2) of the African Charter of Human and People’s Rights. It is to be found in the Geneva Conventions … see Article 99 of Convention III, Article 67 of Convention IV and Article 75(4)(c) of the first Protocol, all relating to criminal trials. It is set out in Article 22(1) of the Statute of the ICC. In the case of the Special Court for Sierra Leone, it was spelled out very plainly in paragraph 12 of the Secretary-General’s Report:
In recognition of the principle of legality, in particular nullum crimen sine lege, and the prohibition on retroactive criminal legislation, the international crimes enumerated are crimes considered to have had the character of customary international law at the time of the alleged commission of the crime.
16. Professor Cassese concludes that “the principle of non-retroactivity of criminal rules is now solidly embodied in international law. It follows that courts may only apply substantive criminal rules that existed at the time of commission of the alleged crime”. There is room for judicial development, but he lays down three rules for such development:
1. It must be in keeping with the rules of criminal liability defining the essence of the offence.
2. It must conform with the fundamental principles of international criminal law.
3. The particular development must be reasonably foreseeable by the defendant.
17. This tripartite test is designed [to] define the limits of judicial “development” of existing legal rules. It is relevant to, but not the same process as, … determining whether and when a rule of customary international law binding on states has developed or changed so as to entail criminal consequences for individuals – as the Secretary-General puts it …, “Whether it is customarily recognised as a war crime entailing the individual responsibility of the accused.” In this context, for an international court to recognise the creation of a new criminal offence without infringing the nullum crimen principle, I would formulate the test as follows:
i. The elements of the offence must be clear and in accordance with fundamental principles of criminal liability.
ii. That the conduct could amount to an offence in international criminal law must have been capable of reasonable ascertainment at the time of commission;
iii There must be evidence (or at least inference) of general agreement by the international community that breach of the customary law rule would or would now, entail international criminal liability for individual perpetrators, in addition to the normative obligation on States to prohibit the conduct in question under their domestic law. 
SCSL, Norman case, Decision on Preliminary Motion Based on Lack of Jurisdiction (Child Recruitment), Appeals Chamber, 31 May 2004, Dissenting Opinion of Justice Robertson, §§ 11 and 13–17.
Extraordinary Chambers in the Courts of Cambodia
In the Kaing case before the ECCC, the accused was charged, both individually and as a superior, with, inter alia, various crimes against humanity and grave breaches of the 1949 Geneva Conventions. In its judgment in 2010, the Trial Chamber considered the principle of legality, stating:
27. Article 15(1) of the [1966] International Covenant on Civil and Political Rights (“ICCPR”) states that “[n]o one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed.” This principle is qualified in Article 15(2) of the ICCPR, which adds: “Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.”
28. The international jurisprudence has clarified that compliance with the principle of legality requires that the offence with which an accused is charged was sufficiently foreseeable and that the law providing for such liability was sufficiently accessible to the accused at the relevant time. A State practice of tolerating or encouraging certain acts will not operate as a bar to their perpetrators being brought to justice and punished where those acts are crimes under national or international law. The principle of legality applies both to the offences as well as to the forms of responsibility.
31. An assessment of the foreseeability and accessibility requirements integral to the principle of legality should take into account the particular nature of international law, including its reliance on unwritten custom. The ICTY Appeals Chamber has noted that,
[a]s to foreseeability, the conduct in question is the concrete conduct of the accused; he must be able to appreciate that the conduct is criminal in the sense generally understood, without reference to any specific provision. As to accessibility, in the case of an international tribunal such as this, accessibility does not exclude reliance being placed on a law which is based on custom. [ICTY, Hadžihasanović case, Decision on Interlocutory Appeal Challenging Jurisdiction in Relation to Command Responsibility, § 34]
32. Further, “[a]lthough the immorality or appalling character of an act is not a sufficient factor to warrant its criminalisation under customary international law, it may in fact play a role in that respect, insofar as it may refute any claim by the Defence that it did not know of the criminal nature of the acts.” [ICTY, Milutinović case, Decision on Dragoljub Ojdanic’s Motion Challenging Jurisdiction – Joint Criminal Enterprise, § 42]
33. The Chamber may also rely on conventional international law where a treaty is (i) unquestionably binding on the parties at the time of the alleged offence and (ii) not in conflict with or derogating from peremptory norms of international law. As stated by the ICTY Appeals Chamber, the principle of legality “is also satisfied where a State is already treaty-bound by a specific convention, and the International Tribunal applies a provision of that convention irrespective of whether it is part of customary international law.” [ICTY, Kordić and Čerkez case, Judgement on Appeal, § 44] International tribunals have in practice nevertheless ascertained whether a treaty provision is also declaratory of custom.
34. The legality principle does not prevent the Chamber from determining an issue through a process of interpretation and clarification of the elements of a particular offence. Nor does it prevent the Chamber from relying on appropriate decisions which interpret particular ingredients of an offence. Specifically, the Chamber’s reliance on decisions of international tribunals that post-date [the alleged offences] does not contravene the principle of legality. Rather, these decisions provide interpretative guidance as regards the evolving status of certain offences and forms of responsibility under international law. In addition, the fact that the ECCC was established and conferred with jurisdiction over offences after they were allegedly committed does not violate the principle of legality. 
ECCC, Kaing case, Judgment, 26 July 2010, §§ 27–28 and 31–34.
[footnotes in original omitted]
Human Rights Committee
In its concluding observations on the combined fourth and fifth periodic reports of Sri Lanka in 2003, the Human Rights Committee stated:
[The Committee] is further concerned that article 15 of the Constitution permits derogation from article 15 of the [1966 International Covenant on Civil and Political Rights], which is non-derogable, by making it possible to impose restrictions on the freedom from retroactive punishment …
The State party should bring the provisions of chapter III of the Constitution into conformity with articles 4 and 15 of the Covenant. 
Human Rights Committee, Concluding observations on the combined fourth and fifth periodic reports of Sri Lanka, UN Doc. CCPR/CO/79/LKA, 1 December 2003, § 8.
[emphasis in original]
Human Rights Committee
In Casafranca de Gomez v. Peru in 2003, the Human Rights Committee held:
With regard to the author’s claims that there was a violation of the principles of non-retroactivity and equality before the law as a result of the application of Act No. 24651 of 6 March 1987, subsequent to the events in the case, the Committee notes that the State party acknowledges that this occurred. While it is true, as asserted by the State party, that acts of terrorism at the time of the events were already offences under Legislative Decree No. 46 of March 1981, it is equally true that Act No. 24651 of 1987 amended the penalties, by imposing higher minimum sentences and thereby making the situation of guilty parties worse. Although [the author’s son] was sentenced to the minimum term of 25 years under the new law, this was more than double compared to the minimum term under the previous law, and the Court gave no explanation as to what would have been the sentence under the old law if still applicable. Accordingly, the Committee finds that there was a violation of article 15 of the [1966 International Covenant on Civil and Political Rights]. 
Human Rights Committee, Casafranca de Gomez v. Peru, Views, 19 September 2003, § 7.4.
European Court of Human Rights
In its judgment in Kokkinakis v. Greece in 1993, the European Court of Human Rights maintained:
Article 7 § 1 of the [1950 European Convention on Human Rights] is not confined to prohibiting the retroactive application of the criminal law to an accused’s disadvantage. It also embodies, more generally, the principle that only the law can define a crime and prescribe a penalty (nullum crimen, nulla poena sine lege) and the principle that the criminal law must not be extensively construed to an accused’s detriment, for instance by analogy; it follows from this that an offence must be clearly defined in law. This condition is satisfied where the individual can know from the wording of the relevant provision and, if need be, with the assistance of the court’s interpretation of it, what acts and omissions will make him liable. 
European Court of Human Rights, Kokkinakis v. Greece, Judgment, 25 May 1993, § 52.
European Court of Human Rights
In its judgment in S.W. v. UK in 1995, the European Court of Human Rights stated:
Article 7 [of the 1950 European Convention on Human Rights] cannot be read as outlawing the gradual clarification of the rules of criminal liability through judicial interpretation from case to case, provided that the resultant development is consistent with the essence of the offence and could reasonably be foreseen. 
European Court of Human Rights, S.W. v. UK, Judgment, 22 November 1995, § 36.
Inter-American Court of Human Rights
In its judgment in the Castillo Petruzzi and Others case in 1999, the Inter-American Court of Human Rights held:
The Court considers that crimes must be classified and described in precise and unambiguous language that narrowly defines the punishable offense, thus giving full meaning to the principle of nullum crimen nulla poena sine lege praevia in criminal law. This means a clear definition of the criminalized conduct, establishing its elements and the factors that distinguish it from behaviors that are either not punishable offences or are punishable but not with imprisonment. Ambiguity in describing crimes creates doubts and the opportunity for abuse of power, particularly when it comes to ascertaining the criminal responsibility of individuals and punishing their criminal behavior with penalties that exact their toll on the things that are most precious, such as life and liberty. Laws of the kind applied in the instant case, that fail to narrowly define the criminal behaviors, violate the principle of nullum crimen nulla poena sine lege praevia recognized in Article 9 of the [1969 American Convention on Human Rights]. 
Inter-American Court of Human Rights, Castillo Petruzzi and Others case, Judgment, 30 May 1999, § 121.
ICRC
To fulfil its task of disseminating IHL, the ICRC has delegates around the world teaching armed and security forces that:
The conviction must be pronounced by an impartial and regularly constituted court respecting the generally recognized principles of regular judicial procedure, which include … law in force at the time the offence was committed (i.e. no retroactive law). 
Frédéric de Mulinen, Handbook on the Law of War for Armed Forces, ICRC, Geneva, 1987, § 202(c).
Turku Declaration of Minimum Humanitarian Standards
The Turku Declaration of Minimum Humanitarian Standards, adopted by an expert meeting convened by the Institute for Human Rights of Åbo Akademi University in Turku/Åbo, Finland in 1990, provides a list of the minimum judicial guarantees, including: “No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under applicable law, at the time when it was committed.” 
Turku Declaration of Minimum Humanitarian Standards, adopted by an expert meeting convened by the Institute for Human Rights, Åbo Akademi University, Turku/Åbo, 30 November–2 December 1990, Article 9(g), IRRC, No. 282, 1991, p. 334.