Règle correspondante
United States of America
Practice Relating to Rule 87. Humane Treatment
Section C. Wounded and sick
The US Field Manual (1956) restates Article 12 of the 1949 Geneva Convention II. 
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, § 215.
The US Air Force Pamphlet (1976) provides: “One of the important principles relating to wounded and sick requires … humane treatment.” 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 3-4(d).
The US Naval Handbook (1995) states: “Wounded and sick personnel falling into enemy hands must be treated humanely.” 
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), § 11-4.
The US Naval Handbook (2007) states: “Wounded and sick personnel falling into enemy hands must be treated humanely.” 
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, § 11.6.
The US Manual on Detainee Operations (2008) states:
Legal Considerations
a. As a subset of military operations, detainee operations must comply with the law of war during all armed conflicts, however such conflicts are characterized, and in all other military operations …
c. The four Geneva Conventions of 1949 are fully applicable as a matter of international law to all military operations that qualify as international armed conflicts … The principles reflected in these treaties are considered customary international law, binding on all nations during international armed conflict. Although often referred to collectively as the “Geneva Conventions,” the specific treaties are:
(1) [1949] Geneva Convention [I] … This convention … requires humane treatment for wounded and sick personnel who fall into enemy hands …
(2) [1949] Geneva Convention [II] … This convention requires the humane treatment and protection of members of the armed forces and other persons at sea who are wounded, sick, or shipwrecked. 
United States, Manual on Detainee Operations, Joint Chiefs of Staff, 30 May 2008, pp. I-2–I-3.
In 1987, the Deputy Legal Adviser of the US Department of State affirmed: “We support the principle that all wounded and sick and shipwrecked be respected and protected.” 
United States, Remarks of 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. 423.
According to the Report on US Practice, it is the opinio juris of the United States that the wounded and sick in internal armed conflicts should be treated humanely. 
Report on US Practice, 1997, Chapter 5.1.