States have important customary and treaty obligations to observe the law of armed conflict, as a matter of national policy, and to insure its implementation, observance and enforcement by [their] own armed forces. 

The US … ensures observance and enforcement through a variety of national means including close command control, military regulations, rules of engagement, the Uniform Code of Military Justice and other national enforcement techniques. 

It is the policy of the United States to apply the law of armed conflict to all circumstances in which the armed forces of the United States are engaged in combat operations, regardless of whether such hostilities are declared or otherwise designated as “war”. 

Article 0705, Observance of International Law states:

At all times, a commander shall observe, and require their commands to observe, the principles of international law. Where necessary to fulfill this responsibility, a departure from other provisions of Navy Regulations is authorized.  [emphasis in original]

The Handbook also states: “U.S. service members are bound by the law of armed conflict as embodied in customary international law and all treaties to which the United States is a party.” 

Various means are available to belligerents under international law for inducing compliance with the law of armed conflict. To establish the facts, the belligerents may agree to an ad hoc inquiry. In the event of a clearly established violation of the law of armed conflict, the aggrieved nation may:

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. Often referred to as the law of armed conflict, the law of war is that part of international law that regulates the conduct of armed hostilities and occupation.

b. The law of war encompasses all international law for the conduct of hostilities binding on the United States or its individual citizens, including treaties and international agreements to which the United States is a party, and applicable customary international law …

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. These treaties are intended to provide comprehensive humanitarian standards for the treatment of war victims without discrimination. The principles reflected in these treaties are considered customary international law, binding on all nations during international armed conflict. 

Mandatory training for PSCs prior to operating in Iraq will include review of relevant USG [US Government] and Iraqi laws, Rules for the Use of Force, Law of Armed Conflict, Graduated Force Procedures, and those relevant … rules and regulations applicable to their contracts, as well as scenario-based training on a standard set of Use-of-Force vignettes … based on recent incidents and threat reporting. Refresher training will occur annually … A failure to maintain training qualifications will generally result in revocation of firearms authorization for the individual. 

[The appellant]’s many arguments present this court with two overarching questions regarding the detainees at the Guantánamo Bay naval base. The first concerns whom the President can lawfully detain pursuant to statutes passed by Congress. The second asks what procedure is due to detainees challenging their detention in habeas corpus proceedings. …

[The appellant] challenges the statutory legitimacy of his detention by advancing a number of arguments based upon the international laws of war. …

Before considering these arguments in detail, we note that all of them rely heavily on the premise that the war powers granted by the AUMF [Authorization for Use of Military Force, Pub. L. No. 107-40, § 2(a), 115 Stat. 224, 224 (2001)] and other statutes are limited by the international laws of war. This premise is mistaken. There is no indication in the AUMF, the Detainee Treatment Act of 2005, Pub. L. No. 109-148, div. A, tit. X, 119 Stat. 2739, 27 41-43, or the MCA [Military Commissions Act] of 2006 or 2009, that Congress intended the international laws of war to act as extra-textual limiting principles for the President’s war powers under the AUMF. The international laws of war as a whole have not been implemented domestically by Congress and are therefore not a source of authority for U.S. courts. See RESTATEMENT (THIRD) OF FOREIGN RELATIONS LAW OF THE UNITED STATES § 111(3)–(4) (1987). Even assuming Congress had at some earlier point implemented the laws of war as domestic law through appropriate legislation, Congress had the power to authorize the President in the AUMF and other later statutes to exceed those bounds. See id § 115(1)(a). Further weakening their relevance to this case, the international laws of war are not a fixed code. Their dictates and application to actual events are by nature contestable and fluid. See id § 102 cmts. b & c (stating there is “no precise formula” to identify a practice as custom and that “[i]t is often difficult to determine when [a custom’s] transformation into law has taken place”). Therefore, while the international laws of war are helpful to courts when identifying the general set of war powers to which the AUMF speaks, see Hamdi Hamdi v. Rumsfeld, 542 U.S. 507] at 520, their lack of controlling legal force and firm definition render their use both inapposite and inadvisable when courts seek to determine the limits of the President’s war powers. Therefore, putting aside that we find Al-Bihani’s reading of international law to be unpersuasive, we have no occasion here to quibble over the intricate application of vague treaty provisions and amorphous customary principles. The sources we look to for resolution of Al-Bihani’s case are the sources courts always look to: the text of relevant statutes and controlling domestic case law.  

We decline to en banc this case to determine the role of international law-of-war principles in interpreting the AUMF because, as the various opinions issued in the case indicate, the panel’s discussion of that question is not necessary to the disposition of the merits. See Al–Bihani v. Obama, 590 F.3d 866, 871, 873–74 (D.C.Cir.2010) (panel opinion); id. at 883–85 (Williams, J., concurring in the judgment); Al–Bihani v. Obama, No. 09–5051, slip op. at 1 (D.C.Cir. Aug. 31, 2010) (Kavanaugh, J., concurring in the denial of rehearing en banc); see also Gov’t’s Resp. to Pet. for Reh’g and Reh’g En Banc at 1–2 (stating that the dispute over the role of the law of war does not “change[ ] the outcome”). 

Common Article 1 of the four 1949 Geneva Conventions for the Protection of War Victims requires that parties to those treaties “respect and ensure respect” for each of those treaties. The obligation to “respect and ensure respect” was binding upon all parties to the Persian Gulf War. It is an affirmative requirement to take all reasonable and necessary steps to bring individuals responsible for war crimes to justice. 

DOD-mandated instruction and training in the law of war were reflected in US operations, which were in keeping with historic US adherence to the precepts of the law of war. Adherence to the law of war impeded neither Coalition planning nor execution; Iraqi violations of the law of war provided Iraq no advantage.

…

The willingness of commanders to seek legal advice at every stage of operational planning ensured US respect for the law of war throughout Operations Desert Shield and Desert Storm. 

The Heads of the DoD Components shall: … ensure that the members of their Components comply with the law of war during all armed conflicts, however such conflicts are characterized, and with the principles and spirit of the law of war during all other operations. 

Where force is necessary, we have a moral and strategic interest in binding ourselves to certain rules of conduct. And even as we confront a vicious adversary that abides by no rules, I believe the United States of America must remain a standard bearer in the conduct of war. That is what makes us different from those whom we fight. That is a source of our strength. … And that is why I have reaffirmed America’s commitment to abide by the Geneva Conventions. We lose ourselves when we compromise the very ideals that we fight to defend. And we honor – we honor those ideals by upholding them not when it’s easy, but when it is hard. 

We live in a time, when, as you know, the United States finds itself engaged in several armed conflicts. …

…

[L]et me address a question on many of your minds: how has this Administration determined to conduct these armed conflicts and to defend our national security, consistent with its abiding commitment to international law? Let there be no doubt: the … Administration is firmly committed to complying with all applicable law, including the laws of war, in all aspects of these on-going armed conflicts. … We in the … Administration have worked hard since we entered office to ensure that we conduct all aspects of these armed conflicts – in particular, detention operations, targeting, and prosecution of terrorist suspects – in a manner consistent not just with the applicable laws of war, but also with the Constitution and laws of the United States.  [emphasis in original]