United States of America
Practice Relating to Rule 27. Religious Personnel
The US Field Manual (1956) restates Article 24 of the 1949 Geneva Convention I.
The US Naval Handbook (1995) states: “Chaplains attached to the armed forces are entitled to respect and protection.”
The Annotated Supplement to the US Naval Handbook (1997) notes: “The United States supports the principle in [Article 15 of the 1977 Additional Protocol I] that civilian … religious personnel be respected and protected and not be made the objects of attack.”
The US Naval Handbook (2007) states: “Chaplains attached to the armed forces are entitled to respect and protection.”
The Handbook also states:
Noncombatants [§ 5.4.2. – “Noncombatants are those members of the armed forces who do not take direct part in hostilities because of their status as medical personnel and chaplains”] may not be deliberately or indiscriminately attacked, unless they forgo their protection by taking a direct part in hostilities.
The Handbook also states:
[C]haplains falling into enemy hands … unless their retention by the enemy is required to provide for the … religious needs of prisoners of war, … must be repatriated at the earliest opportunity.
The US Manual for Military Commissions (2010), Part IV, Crimes and Elements, states: “The term ‘protected person’ means any person entitled to protection under one or more of the  Geneva Conventions, including … military … religious personnel.”
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
“(a) DEFINITIONS AND CONSTRUCTION. – In this section:
“(2) PROTECTED PERSON. – The term “protected person” means any person entitled to protection under one or more of the Geneva Conventions, including –
“(C) military medical or religious personnel.
The US Military Commissions Act (2009) amends Chapter 47A of Title 10 of the United States Code as follows:
“§ 950p. Definitions; construction of certain offenses; common circumstances
“(a) DEFINITIONS.—In this subchapter:
“ (2) The term ‘protected person’ means any person entitled to protection under one or more of the  Geneva Conventions, including … military … religious personnel.
David Hicks, an Australian citizen, was captured in Afghanistan in December 2001 and afterwards detained at Guantanamo Bay Naval Base, Cuba. In March 2007, in the Hicks case, the accused became the first person to be tried and convicted under the US Military Commissions Act of 2006. Following a pre-trial agreement struck with the Convening Authority, the accused pleaded guilty to the charge of “providing material support for terrorism”. In April 2007, Hicks returned to Australia to serve the remaining nine months of a suspended seven-year sentence. In the case’s record of trial for the 30 March 2007 hearing, the military judge defined various terms contained in the charge to which the accused had pleaded guilty:
“Protected person” means any person entitled to protection under one or more of the Geneva Conventions, including: (a) civilians not taking part in hostilities; (b) military personnel placed hors de combat by sickness, wounds, or detention; and (c) military medical or religious personnel.
In 1987, the Deputy Legal Adviser of the US Department of State affirmed that “we support the principle that medical and religious personnel must be respected and protected” as provided in Article 15 of the 1977 Additional Protocol I.
Upon signature of the 1977 Additional Protocols I and II, the United States declared:
It is the understanding of the United States of America that the terms used in Part III of [the 1977 Additional Protocol II] which are the same as the terms defined in Article 8 [of the 1977 Additional Protocol I] shall so far as relevant be construed in the same sense as those definitions.
According to the Report on US Practice, it is the opinio juris
of the United States that medical and religious personnel are not to be knowingly attacked or unnecessarily prevented from performing their duties in either international or non-international armed conflicts.