Related Rule
United States of America
Practice Relating to Rule 5. Definition of Civilians
The US Air Force Pamphlet (1976) states: “Civilians are all persons other than those mentioned as combatants in [Article 4(A) of the 1949 Geneva Convention III].” 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3; see also § 1-2.
The US Naval Handbook (1995) refers first to the notion of non-combatants as primarily applying to “those individuals who do not form part of the armed forces and who otherwise refrain from the commission or direct support of hostile acts. In this context, noncombatants and, generally, the civilian population, are synonymous.” 
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), § 5.3; see also § 11.1.
The manual further specifies: “The civilian population consists of all persons not serving in the armed forces, militia, or paramilitary forces and not otherwise taking a direct part in the hostilities.” 
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), § 11.3.
The US Naval Handbook (2007) states: “A civilian is a person who is not a combatant or noncombatant.” 
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, § 5.4.3.
The Handbook defines noncombatants as “those members of the armed forces who do not take direct part in hostilities because of their status as medical personnel and chaplains.” 
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, § 5.4.2.
In March 2008, in the Hamdan case, a Guantánamo Military Commission considered a Defence motion that, as the accused had been denied the protection of the 1949 Geneva Convention III as a prisoner of war, he was entitled to the protection of the 1949 Geneva Convention IV as a civilian. The Commission denied the Defence motion on the basis that, firstly, the accused (a Yemeni national) did not meet the definition of “protected person” under Geneva Convention IV and, secondly, even had he met the definition, such protection would have been derogated by virtue of his participation as an unlawful combatant. The Commission stated:
Article 4 of GC IV [1949 Geneva Convention IV] identifies “Persons protected by the Convention” in these terms:
Persons protected by the Convention are those who, at a given moment and in any manner whatsoever, find themselves, in case of a conflict or occupation, in the hands of a Party to the conflict or Occupying Power of which they are not nationals.
Nationals of a State which is not bound by the Convention are not protected by it. Nationals of a neutral State who find themselves in the territory of a belligerent State, and nationals of a co-belligerent State, shall not be regarded as protected persons while the State of which they are nationals has normal diplomatic representation in the State in whose hands they are.
Applying this definition to the accused, the Commission finds, for the purposes of this motion, that the accused meets the initial, broad definition of a “protected person” in that he “at any given moment and in any manner whatsoever, [finds himself] … in the hands of a Party to the conflict or Occupying Power of which [he is] not [a] national.” But the second paragraph excludes nationals of a neutral state (such as Yemen) who find themselves in the territory of a belligerent state (such as Afghanistan) “while the state of which they are nationals has normal diplomatic relations” with the State in whose hands they are (such as the United States) … .
… [T]he Commission concludes that the accused is not a “protected person” within the meaning of Article 4 because Yemen then had and continues to have diplomatic relations with the United States.
… [T]he Commission concludes that the Defense has not shown, by a preponderance of the evidence, that the United States presence in Afghanistan was an occupation within the meaning of GC IV or traditional International Law of military occupation. This conclusion reinforces the Commission’s determination that the accused is not a protected person under the Fourth Geneva Convention, and that the relief he seeks, which applies only in occupied territory, should be denied.
The general rule is clearly as the Defense describes it: every person on the battlefield is intended to be protected by one of the Conventions. But this is true only if they meet the requirements of Article 4. The Commission concludes that the accused does not meet those requirements, because he is a citizen of Yemen, which has full diplomatic relations with the United States, and because the United States did not occupy Afghanistan. If the Commission has erred with respect to this conclusion, it likewise appears that his status as an unlawful combatant permits derogation from those rights that would otherwise apply to civilians not engaged in hostilities. He is among that unusual class of persons not protected by either GC III [1949 Geneva Convention III] or GC IV, but entitled to the minimal protections of Common Article 3 [to the 1949 Geneva Conventions]. 
United States, Guantánamo Military Commission, Hamdan case, Ruling, 24 March 2008, pp. 2–5.
In the Hamlily case in 2009, in which the petitioners challenged the legality of their detention at Guantánamo by seeking writs of habeas corpus, the US District Court for the District of Columbia ruled that the US Government’s detention policy is generally consistent with the authority conferred on the US President under the Authorization for Use of Military Force (AUMF), Public Law 107-40, 115 Stat. 224, 18 September 2001, and core law of war principles that govern non-international armed conflicts. In its analysis of the government’s “definitional” framework” providing for the detention of “Taliban or al Qaida forces or associated forces”, the Court stated the following with regard to “civilian” status in armed conflict:
Petitioners argue, just as they did in Gherebi, that because they cannot be classified as “combatants” under Article 4(A) of the Third Geneva Convention [the 1949 Geneva Convention III] or Article 43 of [the 1977] Additional Protocol I, they must be “civilians” – a classification that means they are not subject to military force (i.e., detention) “unless and for such time as they take a direct part in hostilities.” [Additional Protocol I] arts. 51(1), 51(3) … Moreover, the government no longer seeks to detain petitioners on the basis that they are “enemy combatants.” Indeed, the government's abandonment of this term is an implicit acknowledgment that “[i]n non-international armed conflict combatant status does not exist. … The treaty authorities that regulate non-international armed conflicts – Common Article 3, Additional Protocol II and the International Committee of the Red Cross’s Commentaries on both – in fact do not “make any reference whatsoever to the term ‘combatant.’” Gherebi, 2009 WL 1068955, at *18. Gherebi correctly observes that “petitioners evidently interpret this lack of protection for ‘combatants’ in non-international armed conflicts to mean that every individual associated with the enemy to any degree in such a conflict must be treated as a civilian.” Id. Gherebi then explains:
The Geneva Conventions restrict the conduct of the President in armed conflicts; they do not enable it. And the absence of any language in Common Article 3 and [1977] Additional Protocol II regarding prisoners of war or combatants means only that no one fighting on behalf of an enemy force in a non-international armed conflict can lay claim to the protections of such status, not that every signatory to the Geneva Conventions must treat the members of an enemy force in a civil war or transnational conflict as civilians regardless of how important the members in question might be to the command and control of the enemy force or how well organized and coordinated that force might be. Id.
This Court agrees that the lack of combatant status in non-international armed conflicts does not, by default, result in civilian status for all, even those who are members of enemy “organizations” like al Qaeda. 
United States, District Court for the District of Columbia, Hamlily case, Judgment, 19 May 2009, pp. 12–15.
[footnotes in original omitted]