Related Rule
Belgium
Practice Relating to Rule 156. Definition of War Crimes
Belgium’s Law of War Manual (1983) defines as a war crime “any violation of the laws of war … or of the laws of the belligerents, during or on the occasion of war”. However, it criticises this definition, saying that “it includes not only crimes against peace and against humanity … and violations of the laws of war as such … but also violations of the internal legislation of the adversary” which, according to the manual, do not necessarily merit being considered as war crimes. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 54.
The manual states, therefore:
It would be preferable to restrict the term “war crime” to violations that cause outrage to the public conscience owing to their “brutality”, their “inhuman character” or the wilful refusal to recognize rights of property having no connection with military necessity”. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 55.
Under the heading “Grave breaches of the Geneva Conventions”, the manual lists a number of war crimes which are clearly defined and listed as “grave breaches” in the Conventions. It refers to Articles 50–51 of the 1949 Geneva Convention I, Article 51 of the 1949 Geneva Convention II, Article 130 of the 1949 Geneva Convention III and Article 147 of the 1949 Geneva Convention IV, as well as to Articles 11, 85 and 86 of the 1977 Additional Protocol I. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 55.
Belgium’s Penal Code (1867), as amended in 2003, provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such crimes endanger, by act or omission, persons and objects protected by these Conventions, Protocols, laws and customs, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 1.
The Penal Code further provides:
In the case of an armed conflict as defined in … Article 3 common [to the (1949) Geneva Conventions] the grave breaches of [common] Article 3, … listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, objects protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 2.
The Penal Code further states:
The grave breaches set out in Article 15 of the Second Protocol to the 1954 Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict, adopted in The Hague on 26 March 1999, committed in time of armed conflict, as defined in Article 18(1)(2) of the 1954 Hague Convention and in Article 22 of the said Second Protocol, and listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, objects protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Penal Code, 1867, as amended on 5 August 2003, Chapter III, Title I bis, Article 136 quater, § 3.
Belgium’s Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols (1993), as amended in 1999, states:
The grave breaches listed below which cause injury or damage, by act or omission, to persons or objects protected by the Conventions signed at Geneva on 12 August 1949 and approved by the Act of 3 September 1952, and by Protocols I and II additional to those Conventions adopted at Geneva on 8 June 1977 and approved by the Act of 16 April 1986, shall – without prejudice to the criminal provisions applicable to other breaches of the Conventions referred to in the present Act and without prejudice to criminal provisions applicable to breaches committed out of negligence – constitute crimes under international law and be punishable in accordance with the provisions of the present Act. 
Belgium, Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1993, as amended in 1999, Article 1(3).
Belgium’s Law relating to the Repression of Grave Breaches of International Humanitarian Law (1993), as amended in 2003, provides:
War crimes envisaged in the 1949 [Geneva] Conventions … and in the [1977 Additional Protocols I and II] … , as well as in Article 8(2)(f) of the [1998 ICC Statute], and listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such crimes endanger, by act or omission, persons and objects protected by these Conventions, Protocols, laws and customs, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter.
The Law further provides:
In the case of an armed conflict as defined in … Article 3 common [to the (1949) Geneva Conventions] the grave breaches of [common] Article 3, … listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, objects protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 2.
The Law further states:
The grave breaches set out in Article 15 of the Second Protocol to the 1954 Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict, adopted in The Hague on 26 March 1999, committed in time of armed conflict, as defined in Article 18(1)(2) of the 1954 Hague Convention and in Article 22 of the said Second Protocol, and listed below, constitute crimes under international law and shall be punished in accordance with the provisions of the present title, when such breaches endanger, by act or omission, objects protected by these Conventions, without prejudice to criminal provisions applicable to breaches committed out of negligence. 
Belgium, Law relating to the Repression of Grave Breaches of International Humanitarian Law, 1993, as amended on 23 April 2003, Article 1 ter, § 3.
In 1973, during a debate in the Third Committee of the UN General Assembly, the representative of Belgium stated that “with regard to the definition of the concept of war crimes and crimes against humanity, his Government based its position on the Charter of the International Military Tribunal, Nuremberg, and the body of judicial practice to which it had given rise”. 
Belgium, Statement before the Third Committee of the UN General Assembly, UN Doc. A/C.3/SR.2022, 9 November 1973, § 40.
In an explanatory memorandum submitted in 1992 to the Belgian Senate in the context of the adoption of the Draft Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, it was stated that the law reserved the application of other criminal provisions applicable to other breaches of the conventions to which it referred. It further stated that, because of this reservation, “the repression of all violations of the laws and customs of war is covered by ‘ordinary’ national penal law” insofar as the violations correspond to offences punishable under national (penal) law. 
Belgium, Senate, Explanatory Memorandum, Draft Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1990–1991 Session, Doc. 1317-1, 30 April 1991, p. 6.
An early draft of this law was amended in order to include acts committed in the context of non-international conflicts that corresponded to the grave breaches of the 1949 Geneva Conventions and the 1977 Additional Protocol I. Among the reasons for the inclusion of acts committed in the context of non-international conflicts, members of the Senate who submitted the amendment mentioned, inter alia, that international law did not prohibit such criminalization. The amendment was ultimately supported by the Belgian Government, which noted that although the proposals “go further than required by the Conventions and Protocols, they remain within the scope of the – admittedly extensive – application of an international instrument ratified by Belgium”.  
Belgium, Senate, Complementary report submitted on behalf of the Commission of Justice, Draft Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols, 1991–1992 Extraordinary Session, Doc. 481-5, 22 December 1992, pp. 2 ff.
The Report on the Practice of Belgium notes that the Law concerning the Repression of Grave Breaches of the Geneva Conventions and their Additional Protocols shows that Belgium believes that the grave breaches aimed at by the 1949 Geneva Conventions and the 1977 Additional Protocol I are also war crimes when committed in a non-international armed conflict. It further states that the above-mentioned reservation, as well as Belgian practice in the aftermath of the Second World War, when courts, lacking specific legislation in this regard, applied national law to “war crimes”, show that it is Belgium’s opinio juris that the term “war crime” can be a broader one than the technical term of “grave breach” in the meaning of the 1949 Geneva Conventions and the 1977 Additional Protocol I. 
Report on the Practice of Belgium, 1997, Chapter. 6.5.