Related Rule
United States of America
Practice Relating to Rule 89. Violence to Life
The US Field Manual (1956) restates common Article 3 of the 1949 Geneva Conventions. 
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, § 11.
The manual also states that “wilful killing” is a grave breach of the 1949 Geneva Conventions. 
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, § 502.
The manual further provides: “In addition to the ‘grave breaches’ of the Geneva Conventions of 1949, the following acts are representative of violations of the law of war (‘war crimes’): … killing without trial … persons who have committed hostile acts”. 
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, § 504(l).
The US Air Force Pamphlet (1976) states that “wilful killing” is a grave breach of the 1949 Geneva Conventions. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 15-2(b).
The Pamphlet specifies that “wilfully killing without trial persons in custody who have committed hostile acts” in an act involving individual criminal responsibility. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 15-3(c)(10).
The US Air Force Commander’s Handbook (1980) provides: “Even terrorists … and illegal partisans … cannot be summarily executed.” 
United States, Air Force Pamphlet 110-34, Commander’s Handbook on the Law of Armed Conflict, Judge Advocate General, US Department of the Air Force, 25 July 1980, § 4-2(e).
The US Soldier’s Manual (1984) states: “An order to commit a crime such as murder … is in violation of the laws of war.” 
United States, Your Conduct in Combat under the Law of War, Publication No. FM 27-2, Headquarters Department of the Army, Washington, November 1984, p. 26.
The US Instructor’s Guide (1985) provides that violating life and person, in particular murder, is a capital offence prohibited at any time and in any place whatsoever. It specifically prohibits murder of prisoners. 
United States, Instructor’s Guide – The Law of War, Headquarters Department of the Army, Washington, April 1985, pp. 8 and 9.
It also states that “killing, without proper legal trial, … captured persons who have committed hostile acts” is a war crime. 
United States, Instructor’s Guide – The Law of War, Headquarters Department of the Army, Washington, April 1985, p. 14.
The US Naval Handbook (1995) provides that the “killing without just cause” of prisoners of war, civilian inhabitants of occupied territories, the wounded and sick, enemies hors de combat and the shipwrecked is a war crime. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 6.2.5.
The Handbook specifies that “individuals captured as … illegal combatants … may not be summarily executed.” 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 11.7.
The US Manual for Military Commissions (2007), Part IV, Crimes and Elements, includes in the list of crimes triable by military commissions:
MURDER OF PROTECTED PERSONS.
a. Text. “Any person subject to this chapter who intentionally kills one or more protected persons shall be punished by death or such other punishment as a military commission under this chapter may direct.”
b. Elements.
(1) The accused without justification or excuse, intentionally and unlawfully kills a protected person;
(2) The accused knew or should have known of the factual circumstances that established that person’s protected status; and
(3) The killing took place in the context of and was associated with armed conflict.
c. Comment. The intent required for this offense precludes its applicability with regard to collateral damage or death, damage, or injury incident to a lawful attack.
d. Maximum punishment. Death. 
United States, Manual for Military Commissions, published in implementation of the Military Commissions Act of 2006, 10 U.S.C. §§ 948a, et seq., 18 January 2007, Part IV, § 6(1), p. IV-3.
The manual further lists:
MURDER IN VIOLATION OF THE LAW OF WAR.
a. Text. “Any person subject to this chapter who intentionally kills one or more persons, including lawful combatants, in violation of the law of war shall be punished by death or such other punishment as a military commission under this chapter may direct.”
b. Elements.
(1) One or more persons are dead;
(2) The death of the persons resulted from the act or omission of the accused;
(3) The killing was unlawful;
(4) The accused intended to kill the person or persons;
(5) The killing was in violation of the law of war; and
(6) The killing took place in the context of and was associated with an armed conflict.
c. Comment. See comment to “Intentionally Causing Serious Bodily Injury.”
d. Maximum punishment. Death. 
United States, Manual for Military Commissions, published in implementation of the Military Commissions Act of 2006, 10 U.S.C. §§ 948a, et seq., 18 January 2007, Part IV, § 6(15), p. IV-12.
The US Naval Handbook (2007) states:
[T]he following acts are prohibited with respect to detainees in DOD [Department of Defense] custody and control:
a. Violence to life and person, in particular murder …
d. … [C]arrying out executions without previous judgment pronounced by a regularly constituted court, affording all the judicial guarantees that are recognized as indispensable by civilized peoples. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 11.2(a) and (d).
The Handbook also states that examples of war crimes that could be considered as grave breaches of the 1949 Geneva Conventions include:
1. Offenses against prisoners of war, including killing without just cause …
2. Offenses against civilian inhabitants of occupied territory, including killing without just cause …
3. Offenses against the sick and wounded, including killing …
4. Denial of quarter (i.e., killing or wounding an enemy unable to fight …) …
5. Offenses against the survivors of ships and aircraft lost at sea, including killing. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 6.2.6(1)–(5).
The US Manual on Detainee Operations (2008) states:
As a subset of military operations, detainee operations must comply with the law of war during all armed conflicts …
… Common Article 3 to the Geneva Conventions of 1949, as construed and applied by U.S. law, establishes minimum standards for the humane treatment of all persons detained by the United States, coalition, and allied forces. Common Article 3 prohibits at any time and in any place: “violence to life and person, in particular murder of all kinds, … [and] the carrying out of executions without previous judgment pronounced by a regularly constituted court, affording all the judicial guarantees which are recognized as indispensable by civilized peoples … ”. 
United States, Manual on Detainee Operations, Joint Chiefs of Staff, 30 May 2008, pp. I-2–I-3.
The manual further states:
DODD 2310.01E [Department of Defense Directive, The Department of Defense Detainee Program] requires that all DOD [Department of Defense] personnel and contractors will apply, without regard to a detainee’s legal status, at a minimum, the standards articulated in Common Article 3 to the Geneva Conventions of 1949. 
United States, Manual on Detainee Operations, Joint Chiefs of Staff, 30 May 2008, pp. III-11–III-12.
The manual also states:
Planning and preparing for the use of force (UOF) is a necessary element in maintaining order. JFCs [joint force commanders] will ensure that detainee facility security personnel are prepared to employ the effective UOF necessary to protect themselves, other members of the force, or detainees … The use of deadly force against detainees should always be considered a measure of last resort. Its use should be authorized when no other means of suppressing the dangerous activity (attack, escape, etc.) is feasible. Furthermore, use of deadly force should be preceded by warnings appropriate to the circumstances. The continuum shown below recognizes five basic types of subjects:
NOTE: Nothing in this Joint Publication limits a Servicemember’s inherent right to self defense.
(5) Lethal: Attempts to kill or inflict serious injury (e.g., using knives, clubs, thrown objects, firearms).
b. The continuum also incorporates five levels of force (see Figure III-4 [which associates the lethal type of subject to the use of deadly force]). Ideally, the Service member starts at Level 1 and progressively moves up the continuum until the detainee complies. However, the UOF is dictated by the actions of the subject during the encounter. Subject actions may escalate or de-escalate rapidly, possibly skipping one or more levels. The levels of force do not have to be applied in order.
(5) Level 5: Deadly Force. Used as a last resort when all lesser means have failed or would be impractical. Used to prevent death or serious injury to self or others; to prevent the theft, damage, or destruction of resources vital to national security or dangerous to others; to terminate an active escape attempt (e.g., firearms, strikes with nonlethal weapons directed at vital points of the body). 
United States, Manual on Detainee Operations, Joint Chiefs of Staff, 30 May 2008, p. III-12–III-14.
The US Manual for Military Commissions (2010), Part IV, Crimes and Elements, includes in the list of crimes triable by military commissions:
MURDER OF PROTECTED PERSONS.
a. Text. “Any person subject to this chapter who intentionally kills one or more protected persons shall be punished by death or such other punishment as a military commission under this chapter may direct.”
b. Elements.
(1) The accused without justification or excuse, intentionally and unlawfully kills a protected person;
(2) The accused knew or should have known of the factual circumstances that established that person’s protected status; and
(3) The killing took place in the context of and was associated with hostilities.
c. Comment. The intent required for this offense precludes its applicability with regard to collateral damage or death, damage, or injury incident to a lawful attack.
d. Maximum punishment. Death. 
United States, Manual for Military Commissions, published in implementation of Chapter 47A of Title 10, United States Code, as amended by the Military Commissions Act of 2009, 10 U.S.C, §§ 948a, et seq., 27 April 2010, § 5(1), p. IV-3.
The manual further lists:
MURDER IN VIOLATION OF THE LAW OF WAR.
a. Text. “Any person subject to this chapter who intentionally kills one or more persons, including privileged belligerents, in violation of the law of war shall be punished by death or such other punishment as a military commission under this chapter may direct.”
b. Elements.
(1) One or more persons are dead;
(2) The death of the persons resulted from the act or omission of the accused;
(3) The killing was unlawful;
(4) The accused intended to kill the person or persons;
(5) The killing was in violation of the law of war; and
(6) The killing took place in the context of and was associated with an hostilities.
c. Comment. For purposes of offenses (13) [intentionally causing serious bodily injury], (15) [murder in violation of the law of war], (16) [destruction of property in violation of the law of war], and (27) [spying] in Part IV of this Manual (corresponding to offenses enumerated in paragraphs (13), (15), (16), and (27) of § 950t of title 10, United States Code), an accused may be convicted in a military commission for these offenses if the commission finds that the accused employed a means (e.g., poison gas) or method (e.g., perfidy) prohibited by the law of war; intentionally attacked a “protected person” or “protected property” under the law of war; or engaged in conduct traditionally triable by military commission (e.g., spying; murder committed while the accused did not meet the requirements of privileged belligerency) even if such conduct does not violate the international law of war
d. Maximum punishment. Death. 
United States, Manual for Military Commissions, published in implementation of Chapter 47A of Title 10, United States Code, as amended by the Military Commissions Act of 2009, 10 U.S.C, §§ 948a, et seq., 27 April 2010, § 5(15), p. IV-13.
The US Regulations Governing the Trials of Accused War Criminals in the Pacific Region I (1945) established military commissions which had jurisdiction over offences such as extermination, murder of prisoners of war or persons on the seas, hostages or civilians of or in an occupied territory. 
United States, Regulations Governing the Trials of Accused War Criminals in the Pacific Region I, 1945, Regulation 5.
The US Regulations Governing the Trials of Accused War Criminals in the Pacific Region II (1945) established military commissions which had jurisdiction over offences such as the murder of the civilian population of or in occupied territory, prisoners of war or internees or persons on the seas or elsewhere and “extermination … committed against any civilian population”. 
United States, Regulations Governing the Trials of Accused War Criminals in the Pacific Region II, 1945, Regulation 2(b).
Under the US War Crimes Act (1996), violations of common Article 3 and grave breaches of the 1949 Geneva Conventions are war crimes. 
United States, War Crimes Act, 1996, Section 2441(c).
The US War Crimes Act (1996), as amended by the Military Commissions Act (2006), includes in its definition of war crimes any conduct constituting a grave breach of common Article 3 of the 1949 Geneva Conventions:
§ 2441. War crimes
(c) Definition. – As used in this section the term “war crime” means any conduct –
(3) which constitutes a grave breach of common Article 3 (as defined in subsection (d)) when committed in the context of and in association with an armed conflict not of an international character; or
(d) Common Article 3 Violations. –
(1) Prohibited conduct. – In subsection (c)(3), the term “grave breach of common Article 3” means any conduct (such conduct constituting a grave breach of common Article 3 of the international conventions done at Geneva August 12, 1949), as follows:
(D) Murder. – The act of a person who intentionally kills, or conspires or attempts to kill, or kills whether intentionally or unintentionally in the course of committing any other offense under this subsection, one or more persons taking no active part in the hostilities, including those placed out of combat by sickness, wounds, detention, or any other cause.
(3) Inapplicability of certain provisions with respect to collateral damage or incident of lawful attack. – The intent specified for the conduct stated in subparagraph … (D) o[f] paragraph (1) precludes the applicability of those subparagraphs to an offense under subsection (a) by reasons of subsection (c)(3) with respect to –
(A) collateral damage; or
(B) death, damage, or injury incident to a lawful attack.
(5) Definition of grave breaches. – The definitions in this subsection are intended only to define the grave breaches of common Article 3 and not the full scope of United States obligations under that Article. 
United States, War Crimes Act, 1996, 18 United States Code Sec. 2441, as amended by Military Commissions Act ( 2006), 17 October 2006, § 2441(c)(3) and (d).
The US Intelligence Reform and Terrorism Prevention Act (2004) states in Title V–Border Protection, Immigration and Visa Matters; Subtitle E–Treatment of Aliens Who Commit Acts of Torture, Extrajudicial Killings or Other Atrocities Abroad:
§. 5501. Inadmissibility and Deportability of Aliens Who have Committed Acts of Torture or Extrajudicial Killings Abroad
(a) INADMISSIBILITY.—Section 212(a)(3)(E) of the Immigration and Nationality Act (8 U.S.C. 1182(a)(3)(E)) is amended—
(1) in clause (ii), by striking “has engaged in conduct that is defined as genocide for purposes of the International Convention on the Prevention and Punishment of Genocide is inadmissible” and inserting “ordered, incited, assisted, or otherwise participated in conduct outside the United States that would, if committed in the United States or by a United States national, be genocide, as defined in section 1091(a) of title 18, United States Code, is inadmissible”;
(2) by adding at the end the following: “(iii) COMMISSION OF ACTS OF TORTURE OR EXTRAJUDICIAL KILLINGS.—Any alien who, outside the United States, has committed, ordered, incited, assisted, or otherwise participated in the commission of—
“(I) any act of torture, as defined in section 2340 of title 18, United States Code; or
“(II) under color of law of any foreign nation, any extrajudicial killing, as defined in section 3(a) of the Torture Victim Protection Act of 1991 (28 U.S.C. 1350 note),
is inadmissible.”; and
(3) in the subparagraph heading, by striking “PARTICIPANTS IN NAZI PERSECUTION OR GENOCIDE” and inserting “PARTICIPANTS IN NAZI PERSECUTION, GENOCIDE, OR THE COMMISSION OF ANY ACT OF TORTURE OR EXTRAJUDICIAL KILLING”
(b) DEPORTABILITY.—Section 237(a)(4)(D) of such Act (8 U.S.C. 1227(a)(4)(D)) is amended—
(1) by striking “clause (i) or (ii)” and inserting “clause (i), (ii), or (iii)”; and
(2) in the subparagraph heading, by striking “ASSISTED IN NAZI PERSECUTION OR ENGAGED IN GENOCIDE” and inserting “PARTICIPATED IN NAZI PERSECUTION, GENOCIDE, OR THE COMMISSION OF ANY ACT OF TORTURE OR EXTRAJUDICIAL KILLING”. 
United States, Intelligence Reform and Terrorism Prevention Act, 2004, Public Law 108-458, 17 December 2004, Title V, Subtitle E, § 5501(a) and (b).
In July 2006, the US Deputy Secretary of Defense issued a memorandum to senior military and civilian personnel in the Department of Defense (DoD) on the subject of common Article 3 to the 1949 Geneva Conventions and its application to the treatment of detainees:
The Supreme Court Hamdan v. Rumsfeld, 548 US 557, 29 June 2006] has determined that Common Article 3 to the Geneva Conventions of 1949 applies as a matter of law to the conflict with Al Qaeda. The Court found that the military commissions as constituted by the Department of Defense are not consistent with Common Article 3.
It is my understanding that, aside from the military commission procedures, existing DoD orders, policies, directives, execute orders, and doctrine comply with the standards of Common Article 3 … In addition, you will recall the President’s prior directive [President George W. Bush, Memorandum, Humane Treatment of Al Qaeda and Taliban Detainees, 7 February 2002] that “the United States Armed Forces shall continue to treat detainees humanely,” humane treatment being the overarching requirement of Common Article 3.
You will ensure that all DoD personnel adhere to these standards. In this regard, I request that you promptly review all relevant directives, regulations, policies, practices and procedures under your purview to ensure that they comply with the standards of Common Article 3. 
United States, Department of Defense, Deputy Secretary of Defense, Memorandum, Application of Common Article 3 of the Geneva Conventions to the Treatment of Detainees in the Department of Defense, 7 July 2006.
The US Military Commissions Act (2006), passed by Congress following the Supreme Court’s decision in Hamdan v. Rumsfeld in 2006, amends Title 10 of the United States Code as follows:
§ 950v. Crimes triable by military commissions
“ …
“(b) OFFENSES.—The following offenses shall be triable by military commission under this chapter at any time without limitation:
“(1) MURDER OF PROTECTED PERSONS.—Any person subject to this chapter who intentionally kills one or more protected persons shall be punished by death or such other punishment as a military commission under this chapter may direct.
“ …
“(15) MURDER IN VIOLATION OF THE LAW OF WAR.—Any person subject to this chapter who intentionally kills one or more persons, including lawful combatants, in violation of the law of war shall be punished by death or such other punishment as a military commission under this chapter may direct. 
United States, Military Commissions Act, 2006, Public Law 109-366, Chapter 47A of Title 10 of the United States Code, 17 October 2006, pp. 120 Stat. 2626 and 2628, § 950v(b)(1) and (15).
The Military Commissions Act also provides:
Sec. 6. Implementation of Treaty Obligations
“…
“(b) REVISION TO WAR CRIMES OFFENSE UNDER FEDERAL CRIMINAL CODE.—
“(1) IN GENERAL.—Section 2441 of title 18, United States Code, is amended—
“…
“(B) by adding at the end the following new subsection:
“(d) COMMON ARTICLE 3 VIOLATIONS—
“(1) PROHIBITED CONDUCT—In subsection (c)(3), the term “grave breach of common Article 3” means any conduct (such conduct constituting a grave breach of common Article 3 of the international conventions done at Geneva August 12, 1949), as follows:
“…
“(D) MURDER—The act of a person who intentionally kills, or conspires or attempts to kill, or kills whether intentionally or unintentionally in the course of committing any other offense under this subsection, one or more per sons taking no active part in the hostilities, including those placed out of combat by sickness, wounds, detention, or any other cause. 
United States, Military Commissions Act, 2006, Public Law 109-366, Chapter 47A of Title 10 of the United States Code, 17 October 2006, pp. 120 Stat. 2633 and 2634, Sec. 6(b)(1)(B)(d)(1)(D).
In July 2007, and in accordance with section 6(a)(3) of the Military Commissions Act (2006), the US President issued an Executive Order which stated that a “Program of Detention and Interrogation Operated by the Central Intelligence Agency” complied with US obligations under common Article 3 of the 1949 Geneva Conventions. The Executive Order stated, in part:
Sec. 3. Compliance of a Central Intelligence Agency Detention and Interrogation Program with Common Article 3.
(a) Pursuant to the authority of the President under the Constitution and the laws of the United States, including the Military Commissions Act of 2006, this order interprets the meaning and application of the text of Common Article 3 with respect to certain detentions and interrogations, and shall be treated as authoritative for all purposes as a matter of United States law, including satisfaction of the international obligations of the United States. I hereby determine that Common Article 3 shall apply to a program of detention and interrogation operated by the Central Intelligence Agency as set forth in this section. The requirements set forth in this section shall be applied with respect to detainees in such program without adverse distinction as to their race, color, religion or faith, sex, birth, or wealth.
(b) I hereby determine that a program of detention and interrogation approved by the Director of the Central Intelligence Agency fully complies with the obligations of the United States under Common Article 3, provided that:
(i) the conditions of confinement and interrogation practices of the program do not include:
(B) any of the acts prohibited by section 2441(d) of title 18, United States Code, including murder, torture, cruel or inhuman treatment, mutilation or maiming, intentionally causing serious bodily injury, rape, sexual assault or abuse, taking of hostages, or performing of biological experiments;
(C) other acts of violence serious enough to be considered comparable to murder, torture, mutilation, and cruel or inhuman treatment, as defined in section 2441(d) of title 18, United States Code. 
United States, Executive Order 13440, Interpretation of the Geneva Conventions Common Article 3 as Applied to a Program of Detention and Interrogation Operated by the Central Intelligence Agency, 20 July 2007, Sec. 3(a)–(b)(i)(B) and (C).
In 2009, the US President issued Executive Order 13491, Ensuring Lawful Interrogations, which stated:
By the authority vested in me by the Constitution and the laws of the United States of America, in order to improve the effectiveness of human intelligence-gathering, to promote the safe, lawful, and humane treatment of individuals in United States custody and of United States personnel who are detained in armed conflicts, to ensure compliance with the treaty obligations of the United States, including the [1949] Geneva Conventions, and to take care that the laws of the United States are faithfully executed, I hereby order as follows:
Section 1. Revocation. Executive Order 13440 of July 20, 2007, is revoked. All executive directives, orders, and regulations inconsistent with this order, including but not limited to those issued to or by the Central Intelligence Agency (CIA) from September 11, 2001, to January 20, 2009, concerning detention or the interrogation of detained individuals, are revoked to the extent of their inconsistency with this order. Heads of departments and agencies shall take all necessary steps to ensure that all directives, orders, and regulations of their respective departments or agencies are consistent with this order.
Sec. 2. Definitions. As used in this order:
(f) … “violence to life and person” [and] “murder of all kinds” … refer to, and have the same meaning as, those same terms in Common Article 3 [to the 1949 Geneva Conventions].
Sec. 3. Standards and Practices for Interrogation of Individuals in the Custody or Control of the United States in Armed Conflicts.
(a) Common Article 3 Standards as a Minimum Baseline. Consistent with the requirements of the Federal torture statute, 18 U.S.C. 2340–2340A, section 1003 of the Detainee Treatment Act of 2005, 42 U.S.C. 2000dd, the Convention Against Torture, Common Article 3, and other laws regulating the treatment and interrogation of individuals detained in any armed conflict, such persons shall in all circumstances be treated humanely and shall not be subjected to violence to life and person (including murder of all kinds, mutilation, cruel treatment, and torture), nor to outrages upon personal dignity (including humiliating and degrading treatment), whenever such individuals are in the custody or under the effective control of an officer, employee, or other agent of the United States Government or detained within a facility owned, operated, or controlled by a department or agency of the United States. 
United States, Executive Order 13491, Ensuring Lawful Interrogations, 2009, Sections 1, 2(f) and 3(a).
The US Military Commissions Act (2009) amends Chapter 47A of Title 10 of the United States Code as follows:
§ 950t. Crimes triable by military commission
“The following offenses shall be triable by military commission under this chapter at any time without limitation:
“(1) MURDER OF PROTECTED PERSONS.—Any person subject to this chapter who intentionally kills one or more protected persons shall be punished by death or such other punishment as a military commission under this chapter may direct.
“…
“(15) MURDER IN VIOLATION OF THE LAW OF WAR.—Any person subject to this chapter who intentionally kills one or more persons, including privileged belligerents, in violation of the law of war shall be punished by death or such other punishment as a military commission under this chapter may direct. 
United States, Military Commissions Act, 2009, § 950t(1) and (15).
In its judgment in the Dostler case in 1945, the US Military Commission found the accused guilty of the summary execution of 15 US prisoners of war. The Commission considered that the execution of the prisoners of war without trial was contrary to the 1907 Hague Regulations and to customary international law. 
United States, Military Commission at Rome, Dostler case, Judgment, 12 October 1945.
In its judgment in the Jaluit Atoll case in 1945, the US Military Commission in the Far East found the five accused guilty of
wilfully, feloniously, with malice aforethought without justifiable cause, and without trial or other due process, assault and kill, by shooting and stabbing to death, three American fliers … then … captured and unarmed prisoners of war in the custody of the … accused. 
United States, Military Commission in the Far East, The Jaluit Atoll case, Judgment, 7–13 December 1945.
In the Isayama case in 1946, the US Military Commission at Shanghai tried Lieutenant-General Harukei Isayama and other members of the Japanese Military Tribunal on charges that members of the Japanese Military Tribunal did “permit, authorize and direct an illegal, unfair, unwarranted and false trial [of prisoners of war] … upon false and fraudulent evidence and without affording said prisoners of war a fair hearing”. The Commission found that the accused were executed in violation of international law. The Commission found Lieutenant-General Isayama and the seven other accused guilty of all counts alleged. 
United States, Military Commission at Shanghai, Isayama case, Judgment, 25 July 1946.
In its judgment in the List case (The Hostages Trial) in 1948, the US Military Tribunal at Nuremberg found ten of the accused, former high-ranking officers in the German army, guilty of offences committed by troops under their command, in particular murder of civilians, used as a means of maintaining order in occupied territories in the face of guerrilla opposition. 
United States, Military Tribunal at Nuremberg, List case (The Hostages Trial), Judgment, 19 February 1948.
In its judgment in the Schultz case in 1969, a US Court of Military Appeal upheld a court-martial conviction of a soldier for killing a person who, the soldier believed, had signalled enemy guerrillas with a light. While the Court recognized that this act could have been considered as an unauthorized communication with the enemy, it held that the victim was entitled to protection against summary execution once he had been taken prisoner. The Court referred to the 1949 Geneva Convention IV and identified murder, manslaughter and assaults as “crimes universally recognized as properly punishable under the law of war”. 
United States, Court of Military Appeals, Schultz case, Judgment, 7 March 1969.
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 the question of whether the use of herbicides constituted extrajudicial killing, the Court stated:
The use of herbicides in Vietnam does not fit within the definition of either torture or extrajudicial killing. Plaintiffs were not within the defendants’ custody or physical control, nor that of the United States, when herbicides were used. Nor were herbicides used to intentionally inflict pain and suffering. They were used to kill plants.
Herbicide spraying by the United States did not constitute “willful killing” or “wilfully causing great suffering or serious injury to body or health” since the United States lacked the requisite criminal intent. 
United States, Eastern States District Court (EDNY), Agent Orange case, Judgment, 28 March 2005, pp. 176–177 and 179.
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 [the accused], 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 …, in violation of the law of war, by throwing a hand grenade at U.S. forces resulting in the death of Sergeant First Class …. 
United States, Guantánamo Military Commission, Khadr case, Ruling, 21 April 2008, § 2.
The Commission then noted that the US Manual for Military Commissions (2007) contained both the text of §950v(b)(15) and the Secretary [for Defense’s] implementation of the statute. Also noted was paragraph 6(13) of the manual, containing Comment to “Intentionally Causing Serious Bodily Injury”:
For the accused to have been acting in violation of the law of war, the accused must have taken acts as a combatant without having met the requirements for lawful combatancy. It is generally accepted international practice that unlawful enemy combatants may be prosecuted for offenses associated with armed conflicts, such as murder; such unlawful enemy combatants do not enjoy combatant immunity because they have failed to meet the requirements of lawful combatancy under the law of war. 
United States, Guantánamo Military Commission, Khadr case, Ruling, 21 April 2008, § 3.c.
The Commission then stated the following in relation to the lawfulness of the offence of murder being tried by US military commissions:
4. Congress possesses express enumerated authority under Article I, Section 8, Clause 10 of the Constitution to enact the Military Commissions Act of 2006. The plenary power given to Congress “to define and punish Piracies and Felonies committed on the high seas, and Offences against the Law of Nations” establishes the prima facie validity of the statute in question.
5. The Supreme Court has recognized that Congress could define offenses against the Law of Nations:
It is no objection that Congress in providing for the trial of such offenses has not itself undertaken to codify that branch of international law or to mark its precise boundaries, or to enumerate or define by statute all the acts which that law condemns. … 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. It chose the latter course. Ex Parte Quirin, 317 U.S. 1, 12, 63 S.Ct. 2 (1942).
6. As if anticipating the defense motion in this case, the Supreme Court actually defined those who are protected by the Law of Nations and those who are not:
By universal agreement and practice the law of war draws a distinction between the armed forces and the peaceful populations of belligerent nations and also between those who are lawful and unlawful combatants. Lawful combatants are subject to capture and detention as prisoners of war by opposing military forces. Unlawful combatants are likewise subject to capture and detention, but in addition they are subject to trial and punishment by military tribunals for acts which render their belligerency unlawful. … [A]n enemy combatant who without uniform comes secretly through the lines for the purpose of waging war by destruction of life or property, … [is a familiar … example of a belligerent who is] generally deemed not to be entitled to the status of prisoners of war, but to be … [an offender] against the law of war subject to trial and punishment by military tribunals. (Ex Parte Quirin, Id., at 12, emphasis added)
7. The commission has considered the cases and authorities cited by the defense and prosecution and finds:
1) There was a reasonable basis for Congress, in 2006, to determine that the offense of murder in violation of the law of war was part of the common law of war, before, on, and after 11 September 2001; and,
2) There was a reasonable basis for Congress, in 2006, to determine that the offense of murder in violation of the law of war was punishable by military commissions, before, on, and after 11 September 2001.
9. The commission has reviewed Charge I and its Specification. The Specification alleges a violation of the statute. The act alleged in the Specification, the killing of a lawful combatant by an unlawful combatant, is a violation of the law of war. 
United States, Guantánamo Military Commission, Khadr case, Ruling, 21 April 2008, §§ 4–7 and 9.
[emphasis in original]
In 1992, in reports submitted pursuant to paragraph 5 of UN Security Council Resolution 771 (1992) on grave breaches of the 1949 Geneva Convention IV committed in the former Yugoslavia, the United States described acts of “wilful killing” and “summary executions” perpetrated by the parties to the conflict. 
United States, Former Yugoslavia: Grave Breaches of the Fourth Geneva Convention, annexed to Letter dated 22 September 1992 to the UN Secretary-General, UN Doc. S/24583, 23 September 1992, pp. 4–6; Former Yugoslavia: Grave Breaches of the Fourth Geneva Convention (Second Submission), annexed to Letter dated 22 October 1992 to the UN Secretary-General, UN Doc. S/24705, 23 October 1992, pp. 4–10; Former Yugoslavia: Grave Breaches of the Fourth Geneva Convention (Third Submission), annexed to Letter dated 5 November 1992 to the UN Secretary-General, UN Doc. S/24791, 10 November 1992, pp. 3–11; Former Yugoslavia: Grave Breaches of the Fourth Geneva Convention (Fourth Submission), annexed to Letter dated 7 December 1992 to the UN Secretary-General, UN Doc. S/24918, 8 December 1992, pp. 3–11.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense listed Iraqi war crimes, including the murder of civilians. It also noted specific Iraqi war crimes, including wilful killing in violation of Articles 32 and 147 of the 1949 Geneva Convention IV. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, pp. 632 and 634.
In its written statement submitted to the ICJ in the Nuclear Weapons case in 1995, the United States held that none of the instruments asserting the right to life prohibited, directly or indirectly, the taking of life for legitimate purposes, including in the exercise of the right to self-defence. It added that these provisions were clearly understood by their drafters as to exclude the lawful taking of life. 
United States, Written statement submitted to the ICJ, Nuclear Weapons case, 20 June 1995, p. 20.
In a concurrent resolution adopted in 2000, the US Congress expressed its sense concerning the war crimes committed by the Japanese military during the Second World War, in particular the beating to death and summary executions of many US military and civilian prisoners. 
United States, House of Representatives (Senate concurring), Concurrent Resolution, H.CON.RES. 357, 106th Congress, 2nd Session, 19 June 2000.
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].” 
Report on US Practice, 1997, Chapter 5.3.