Règle correspondante
United States of America
Practice Relating to Rule 87. Humane Treatment
Section A. General
The US Field Manual (1956) restates common Article 3 of the 1949 Geneva Conventions:
Under the terms of Common Article 3, the parties to a non-international armed conflict occurring in the territory of a party to the Conventions are obliged to apply “as a minimum”, the following provisions:
(1) Persons taking no active part in the hostilities, including members of armed forces who have laid down their arms and those placed hors de combat by sickness, wounds, detention, or any other cause, shall in all circumstances be treated humanely, without any adverse distinction founded on race, colour, religion or faith, sex, birth or wealth, or any other similar criteria. 
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.
According to the US Air Force Pamphlet (1976), common Article 3 of the 1949 Geneva Conventions “represents the first attempt to provide protection for victims of all internal armed conflicts. Its general provisions insure humane treatment to civilians and others who are hors de combat.” 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 11-3.
The US Soldier’s Manual (1984) states that the “humane treatment of non-combatants may produce valuable information, gain active support and deny support for the enemy. Mistreatment serves only the interests of the enemy.” The manual specifies that non-combatants include civilians, medical personnel, chaplains, detained or captured persons and the wounded and sick. 
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. 5.
The US Instructor’s Guide (1985) provides that the rules of IHL “are based on one general principle: treat all non-combatants … humanely”. 
United States, Instructor’s Guide – The Law of War, Headquarters Department of the Army, Washington, April 1985, pp. 4, 8 and 17.
Under the US War Crimes Act (1996), violations of common Article 3 of the 1949 Geneva Conventions are war crimes. 
United States, War Crimes Act, 1996, Section 2441(c).
In 1987, the Deputy Legal Adviser of the US Department of State affirmed:
We support in particular the fundamental guarantees contained in Article 75 [of the 1977 Additional Protocol I] such as the principle that all persons who are in the power of a party to a conflict and who do not benefit from more favorable treatment under the Conventions be treated humanely in all circumstances and enjoy, at a minimum, the protections specified in the Conventions. 
United States, Remarks by Michael J. Matheson, Deputy Legal Adviser, US Department of State, The Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law: A Workshop on Customary International Law and the 1977 Protocols Additional to the 1949 Geneva Conventions, American University Journal of International Law and Policy, Vol. 2, 1987, p. 427.
The Report on US Practice states: “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.