PART 1 OF 2
Opinion of O’Connor, J.
NOTICE: This opinion is subject to formal revision before publication in the preliminary print of the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order that corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
No. 03—6696
YASER ESAM HAMDI and ESAM FOUAD HAMDI, as
next friend of YASER ESAM HAMDI, PETITION-
ERS v. DONALD H. RUMSFELD, SECRETARY
OF DEFENSE, et al.
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FOURTH CIRCUIT
[June 28, 2004]
Justice O’Connor announced the judgment of the Court and delivered an opinion, in which The Chief Justice, Justice Kennedy, and Justice Breyer join.
At this difficult time in our Nation’s history, we are called upon to consider the legality of the Government’s detention of a United States citizen on United States soil as an “enemy combatant” and to address the process that is constitutionally owed to one who seeks to challenge his classification as such. The United States Court of Appeals for the Fourth Circuit held that petitioner’s detention was legally authorized and that he was entitled to no further opportunity to challenge his enemy-combatant label. We now vacate and remand. We hold that although Congress authorized the detention of combatants in the narrow circumstances alleged here, due process demands that a citizen held in the United States as an enemy combatant be given a meaningful opportunity to contest the factual basis for that detention before a neutral decisionmaker.
I
On September 11, 2001, the al Qaeda terrorist network used hijacked commercial airliners to attack prominent targets in the United States. Approximately 3,000 people were killed in those attacks. One week later, in response to these “acts of treacherous violence,” Congress passed a resolution authorizing the President to “use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks” or “harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.” Authorization for Use of Military Force (“the AUMF”), 115 Stat. 224. Soon thereafter, the President ordered United States Armed Forces to Afghanistan, with a mission to subdue al Qaeda and quell the Taliban regime that was known to support it.
This case arises out of the detention of a man whom the Government alleges took up arms with the Taliban during this conflict. His name is Yaser Esam Hamdi. Born an American citizen in Louisiana in 1980, Hamdi moved with his family to Saudi Arabia as a child. By 2001, the parties agree, he resided in Afghanistan. At some point that year, he was seized by members of the Northern Alliance, a coalition of military groups opposed to the Taliban government, and eventually was turned over to the United States military. The Government asserts that it initially detained and interrogated Hamdi in Afghanistan before transferring him to the United States Naval Base in Guantanamo Bay in January 2002. In April 2002, upon learning that Hamdi is an American citizen, authorities transferred him to a naval brig in Norfolk, Virginia, where he remained until a recent transfer to a brig in Charleston, South Carolina. The Government contends that Hamdi is an “enemy combatant,” and that this status justifies holding him in the United States indefinitely–without formal charges or proceedings–unless and until it makes the determination that access to counsel or further process is warranted.
In June 2002, Hamdi’s father, Esam Fouad Hamdi, filed the present petition for a writ of habeas corpus under 28 U.S.C. § 2241 in the Eastern District of Virginia, naming as petitioners his son and himself as next friend. The elder Hamdi alleges in the petition that he has had no contact with his son since the Government took custody of him in 2001, and that the Government has held his son “without access to legal counsel or notice of any charges pending against him.” App. 103, 104. The petition contends that Hamdi’s detention was not legally authorized. Id., at 105. It argues that, “[a]s an American citizen, … Hamdi enjoys the full protections of the Constitution,” and that Hamdi’s detention in the United States without charges, access to an impartial tribunal, or assistance of counsel “violated and continue[s] to violate the Fifth and Fourteenth Amendments to the United States Constitution.” Id., at 107. The habeas petition asks that the court, among other things, (1) appoint counsel for Hamdi; (2) order respondents to cease interrogating him; (3) declare that he is being held in violation of the Fifth and Fourteenth Amendments; (4) “[t]o the extent Respondents contest any material factual allegations in this Petition, schedule an evidentiary hearing, at which Petitioners may adduce proof in support of their allegations”; and (5) order that Hamdi be released from his “unlawful custody.” Id., at 108—109. Although his habeas petition provides no details with regard to the factual circumstances surrounding his son’s capture and detention, Hamdi’s father has asserted in documents found elsewhere in the record that his son went to Afghanistan to do “relief work,” and that he had been in that country less than two months before September 11, 2001, and could not have received military training. Id., at 188—189. The 20-year-old was traveling on his own for the first time, his father says, and “[b]ecause of his lack of experience, he was trapped in Afghanistan once that military campaign began.” Id., at 188—189.
The District Court found that Hamdi’s father was a proper next friend, appointed the federal public defender as counsel for the petitioners, and ordered that counsel be given access to Hamdi. Id., at 113—116. The United States Court of Appeals for the Fourth Circuit reversed that order, holding that the District Court had failed to extend appropriate deference to the Government’s security and intelligence interests. 296 F.3d 278, 279, 283 (2002). It directed the District Court to consider “the most cautious procedures first,” id., at 284, and to conduct a deferential inquiry into Hamdi’s status, id., at 283. It opined that “if Hamdi is indeed an ‘enemy combatant’ who was captured during hostilities in Afghanistan, the government’s present detention of him is a lawful one.” Ibid.
On remand, the Government filed a response and a motion to dismiss the petition. It attached to its response a declaration from one Michael Mobbs (hereinafter “Mobbs Declaration”), who identified himself as Special Advisor to the Under Secretary of Defense for Policy. Mobbs indicated that in this position, he has been “substantially involved with matters related to the detention of enemy combatants in the current war against the al Qaeda terrorists and those who support and harbor them (including the Taliban).” App. 148. He expressed his “familiar[ity]” with Department of Defense and United States military policies and procedures applicable to the detention, control, and transfer of al Qaeda and Taliban personnel, and declared that “[b]ased upon my review of relevant records and reports, I am also familiar with the facts and circumstances related to the capture of … Hamdi and his detention by U.S. military forces.” Ibid.
Mobbs then set forth what remains the sole evidentiary support that the Government has provided to the courts for Hamdi’s detention. The declaration states that Hamdi “traveled to Afghanistan” in July or August 2001, and that he thereafter “affiliated with a Taliban military unit and received weapons training.” Ibid. It asserts that Hamdi “remained with his Taliban unit following the attacks of September 11” and that, during the time when Northern Alliance forces were “engaged in battle with the Taliban,” “Hamdi’s Taliban unit surrendered” to those forces, after which he “surrender[ed] his Kalishnikov assault rifle” to them. Id., at 148—149. The Mobbs Declaration also states that, because al Qaeda and the Taliban “were and are hostile forces engaged in armed conflict with the armed forces of the United States,” “individuals associated with” those groups “were and continue to be enemy combatants.” Id., at 149. Mobbs states that Hamdi was labeled an enemy combatant “[b]ased upon his interviews and in light of his association with the Taliban.” Ibid. According to the declaration, a series of “U.S. military screening team[s]” determined that Hamdi met “the criteria for enemy combatants,” and “a subsequent interview of Hamdi has confirmed that he surrendered and gave his firearm to Northern Alliance forces, which supports his classification as an enemy combatant.” Id., at 149—150.
After the Government submitted this declaration, the Fourth Circuit directed the District Court to proceed in accordance with its earlier ruling and, specifically, to “ ‘consider the sufficiency of the Mobbs Declaration as an independent matter before proceeding further.’ ” 316 F.3d at 450, 462 (2003). The District Court found that the Mobbs Declaration fell “far short” of supporting Hamdi’s detention. App. 292. It criticized the generic and hearsay nature of the affidavit, calling it “little more than the government’s ‘say-so.’ ” Id., at 298. It ordered the Government to turn over numerous materials for in camera review, including copies of all of Hamdi’s statements and the notes taken from interviews with him that related to his reasons for going to Afghanistan and his activities therein; a list of all interrogators who had questioned Hamdi and their names and addresses; statements by members of the Northern Alliance regarding Hamdi’s surrender and capture; a list of the dates and locations of his capture and subsequent detentions; and the names and titles of the United States Government officials who made the determinations that Hamdi was an enemy combatant and that he should be moved to a naval brig. Id., at 185—186. The court indicated that all of these materials were necessary for “meaningful judicial review” of whether Hamdi’s detention was legally authorized and whether Hamdi had received sufficient process to satisfy the Due Process Clause of the Constitution and relevant treaties or military regulations. Id., at 291—292.
The Government sought to appeal the production order, and the District Court certified the question of whether the Mobbs Declaration, “ ‘standing alone, is sufficient as a matter of law to allow meaningful judicial review of [Hamdi’s] classification as an enemy combatant.’ ” 316 F.3d, at 462. The Fourth Circuit reversed, but did not squarely answer the certified question. It instead stressed that, because it was “undisputed that Hamdi was captured in a zone of active combat in a foreign theater of conflict,” no factual inquiry or evidentiary hearing allowing Hamdi to be heard or to rebut the Government’s assertions was necessary or proper. Id., at 459. Concluding that the factual averments in the Mobbs Declaration, “if accurate,” provided a sufficient basis upon which to conclude that the President had constitutionally detained Hamdi pursuant to the President’s war powers, it ordered the habeas petition dismissed. Id., at 473. The Fourth Circuit emphasized that the “vital purposes” of the detention of uncharged enemy combatants–preventing those combatants from rejoining the enemy while relieving the military of the burden of litigating the circumstances of wartime captures halfway around the globe–were interests “directly derived from the war powers of Articles I and II.” Id., at 465—466. In that court’s view, because “Article III contains nothing analogous to the specific powers of war so carefully enumerated in Articles I and II,” id., at 463, separation of powers principles prohibited a federal court from “delv[ing] further into Hamdi’s status and capture,” id., at 473. Accordingly, the District Court’s more vigorous inquiry “went far beyond the acceptable scope of review.” Ibid.
On the more global question of whether legal authorization exists for the detention of citizen enemy combatants at all, the Fourth Circuit rejected Hamdi’s arguments that 18 U.S.C. § 4001(a) and Article 5 of the Geneva Convention rendered any such detentions unlawful. The court expressed doubt as to Hamdi’s argument that §4001(a), which provides that “[n]o citizen shall be imprisoned or otherwise detained by the United States except pursuant to an Act of Congress,” required express congressional authorization of detentions of this sort. But it held that, in any event, such authorization was found in the post-September 11 Authorization for Use of Military Force. 316 F.3d, at 467. Because “capturing and detaining enemy combatants is an inherent part of warfare,” the court held, “the ‘necessary and appropriate force’ referenced in the congressional resolution necessarily includes the capture and detention of any and all hostile forces arrayed against our troops.” Ibid.; see also id., at 467—468 (noting that Congress, in 10 U.S.C. § 956(5), had specifically authorized the expenditure of funds for keeping prisoners of war and persons whose status was determined “to be similar to prisoners of war,” and concluding that this appropriation measure also demonstrated that Congress had “authorized [these individuals’] detention in the first instance”). The court likewise rejected Hamdi’s Geneva Convention claim, concluding that the convention is not self-executing and that, even if it were, it would not preclude the Executive from detaining Hamdi until the cessation of hostilities. 316 F.3d, at 468—469.
Finally, the Fourth Circuit rejected Hamdi’s contention that its legal analyses with regard to the authorization for the detention scheme and the process to which he was constitutionally entitled should be altered by the fact that he is an American citizen detained on American soil. Relying on Ex parte Quirin, 317 U.S. 1 (1942), the court emphasized that “[o]ne who takes up arms against the United States in a foreign theater of war, regardless of his citizenship, may properly be designated an enemy combatant and treated as such.” 316 F.3d, at 475. “The privilege of citizenship,” the court held, “entitles Hamdi to a limited judicial inquiry into his detention, but only to determine its legality under the war powers of the political branches. At least where it is undisputed that he was present in a zone of active combat operations, we are satisfied that the Constitution does not entitle him to a searching review of the factual determinations underlying his seizure there.” Ibid.
The Fourth Circuit denied rehearing en banc, 337 F.3d 335 (2003), and we granted certiorari. 540 U.S. __ (2004). We now vacate the judgment below and remand.
II
The threshold question before us is whether the Executive has the authority to detain citizens who qualify as “enemy combatants.” There is some debate as to the proper scope of this term, and the Government has never provided any court with the full criteria that it uses in classifying individuals as such. It has made clear, however, that, for purposes of this case, the “enemy combatant” that it is seeking to detain is an individual who, it alleges, was “ ‘part of or supporting forces hostile to the United States or coalition partners’ ” in Afghanistan and who “ ‘engaged in an armed conflict against the United States’ ” there. Brief for Respondents 3. We therefore answer only the narrow question before us: whether the detention of citizens falling within that definition is authorized.
The Government maintains that no explicit congressional authorization is required, because the Executive possesses plenary authority to detain pursuant to Article II of the Constitution. We do not reach the question whether Article II provides such authority, however, because we agree with the Government’s alternative position, that Congress has in fact authorized Hamdi’s detention, through the AUMF.
Our analysis on that point, set forth below, substantially overlaps with our analysis of Hamdi’s principal argument for the illegality of his detention. He posits that his detention is forbidden by 18 U.S.C. § 4001(a). Section 4001(a) states that “[n]o citizen shall be imprisoned or otherwise detained by the United States except pursuant to an Act of Congress.” Congress passed §4001(a) in 1971 as part of a bill to repeal the Emergency Detention Act of 1950, 50 U.S.C. § 811 et seq., which provided procedures for executive detention, during times of emergency, of individuals deemed likely to engage in espionage or sabotage. Congress was particularly concerned about the possibility that the Act could be used to reprise the Japanese internment camps of World War II. H. R. Rep. No. 92—116 (1971); id., at 4 (“The concentration camp implications of the legislation render it abhorrent”). The Government again presses two alternative positions. First, it argues that §4001(a), in light of its legislative history and its location in Title 18, applies only to “the control of civilian prisons and related detentions,” not to military detentions. Brief for Respondents 21. Second, it maintains that §4001(a) is satisfied, because Hamdi is being detained “pursuant to an Act of Congress”–the AUMF. Id., at 21—22. Again, because we conclude that the Government’s second assertion is correct, we do not address the first. In other words, for the reasons that follow, we conclude that the AUMF is explicit congressional authorization for the detention of individuals in the narrow category we describe (assuming, without deciding, that such authorization is required), and that the AUMF satisfied §4001(a)’s requirement that a detention be “pursuant to an Act of Congress” (assuming, without deciding, that §4001(a) applies to military detentions).
The AUMF authorizes the President to use “all necessary and appropriate force” against “nations, organizations, or persons” associated with the September 11, 2001, terrorist attacks. 115 Stat. 224. There can be no doubt that individuals who fought against the United States in Afghanistan as part of the Taliban, an organization known to have supported the al Qaeda terrorist network responsible for those attacks, are individuals Congress sought to target in passing the AUMF. We conclude that detention of individuals falling into the limited category we are considering, for the duration of the particular conflict in which they were captured, is so fundamental and accepted an incident to war as to be an exercise of the “necessary and appropriate force” Congress has authorized the President to use.
The capture and detention of lawful combatants and the capture, detention, and trial of unlawful combatants, by “universal agreement and practice,” are “important incident[s] of war.” Ex parte Quirin, 317 U.S., at 28. The purpose of detention is to prevent captured individuals from returning to the field of battle and taking up arms once again. Naqvi, Doubtful Prisoner-of-War Status, 84 Int’l Rev. Red Cross 571, 572 (2002) (“[C]aptivity in war is ‘neither revenge, nor punishment, but solely protective custody, the only purpose of which is to prevent the prisoners of war from further participation in the war’ ” (quoting decision of Nuremberg Military Tribunal, reprinted in 41 Am. J. Int’l L. 172, 229 (1947)); W. Winthrop, Military Law and Precedents 788 (rev. 2d ed. 1920) (“The time has long passed when ‘no quarter’ was the rule on the battlefield … . It is now recognized that ‘Captivity is neither a punishment nor an act of vengeance,’ but ‘merely a temporary detention which is devoid of all penal character.’ … ‘A prisoner of war is no convict; his imprisonment is a simple war measure.’ ” (citations omitted); cf. In re Territo, 156 F.2d 142, 145 (CA9 1946) (“The object of capture is to prevent the captured individual from serving the enemy. He is disarmed and from then on must be removed as completely as practicable from the front, treated humanely, and in time exchanged, repatriated, or otherwise released” (footnotes omitted)).
There is no bar to this Nation’s holding one of its own citizens as an enemy combatant. In Quirin, one of the detainees, Haupt, alleged that he was a naturalized United States citizen. 317 U.S., at 20. We held that “[c]itizens who associate themselves with the military arm of the enemy government, and with its aid, guidance and direction enter this country bent on hostile acts, are enemy belligerents within the meaning of … the law of war.” Id., at 37—38. While Haupt was tried for violations of the law of war, nothing in Quirin suggests that his citizenship would have precluded his mere detention for the duration of the relevant hostilities. See id., at 30—31. See also Lieber Code, ¶153, Instructions for the Government of Armies of the United States in the Field, Gen. Order No. 100 (1863), reprinted in 2 Lieber, Miscellaneous Writings, p. 273 (contemplating, in code binding the Union Army during the Civil War, that “captured rebels” would be treated “as prisoners of war”). Nor can we see any reason for drawing such a line here. A citizen, no less than an alien, can be “part of or supporting forces hostile to the United States or coalition partners” and “engaged in an armed conflict against the United States,” Brief for Respondents 3; such a citizen, if released, would pose the same threat of returning to the front during the ongoing conflict.
In light of these principles, it is of no moment that the AUMF does not use specific language of detention. Because detention to prevent a combatant’s return to the battlefield is a fundamental incident of waging war, in permitting the use of “necessary and appropriate force,” Congress has clearly and unmistakably authorized detention in the narrow circumstances considered here.
Hamdi objects, nevertheless, that Congress has not authorized the indefinite detention to which he is now subject. The Government responds that “the detention of enemy combatants during World War II was just as ‘indefinite’ while that war was being fought.” Id., at 16. We take Hamdi’s objection to be not to the lack of certainty regarding the date on which the conflict will end, but to the substantial prospect of perpetual detention. We recognize that the national security underpinnings of the “war on terror,” although crucially important, are broad and malleable. As the Government concedes, “given its unconventional nature, the current conflict is unlikely to end with a formal cease-fire agreement.” Ibid. The prospect Hamdi raises is therefore not far-fetched. If the Government does not consider this unconventional war won for two generations, and if it maintains during that time that Hamdi might, if released, rejoin forces fighting against the United States, then the position it has taken throughout the litigation of this case suggests that Hamdi’s detention could last for the rest of his life.
It is a clearly established principle of the law of war that detention may last no longer than active hostilities. See Article 118 of the Geneva Convention (III) Relative to the Treatment of Prisoners of War, Aug. 12, 1949, [1955] 6 U.S. T. 3316, 3406, T. I. A. S. No. 3364 (“Prisoners of war shall be released and repatriated without delay after the cessation of active hostilities”). See also Article 20 of the Hague Convention (II) on Laws and Customs of War on Land, July 29, 1899, 32 Stat. 1817 (as soon as possible after “conclusion of peace”); Hague Convention (IV), supra, Oct. 18, 1907, 36 Stat. 2301(“conclusion of peace” (Art. 20)); Geneva Convention, supra, July 27, 1929, 47 Stat. 2055 (repatriation should be accomplished with the least possible delay after conclusion of peace (Art. 75)); Praust, Judicial Power to Determine the Status and Rights of Persons Detained without Trial, 44 Harv. Int’l L. J. 503, 510—511 (2003) (prisoners of war “can be detained during an armed conflict, but the detaining country must release and repatriate them ‘without delay after the cessation of active hostilities,’ unless they are being lawfully prosecuted or have been lawfully convicted of crimes and are serving sentences” (citing Arts. 118, 85, 99, 119, 129, Geneva Convention (III), 6 T. I .A. S., at 3384, 3392, 3406, 3418)).
Hamdi contends that the AUMF does not authorize indefinite or perpetual detention. Certainly, we agree that indefinite detention for the purpose of interrogation is not authorized. Further, we understand Congress’ grant of authority for the use of “necessary and appropriate force” to include the authority to detain for the duration of the relevant conflict, and our understanding is based on longstanding law-of-war principles. If the practical circumstances of a given conflict are entirely unlike those of the conflicts that informed the development of the law of war, that understanding may unravel. But that is not the situation we face as of this date. Active combat operations against Taliban fighters apparently are ongoing in Afghanistan. See, e.g., Constable, U.S. Launches New Operation in Afghanistan, Washington Post, Mar. 14, 2004, p. A22 (reporting that 13,500 United States troops remain in Afghanistan, including several thousand new arrivals); J. Abizaid, Dept. of Defense, Gen. Abizaid Central Command Operations Update Briefing, Apr. 30, 2004, http://www.defenselink.mil/transcripts/ ... 0-1402.htm l (as visited June 8, 2004, and available in the Clerk of Court’s case file) (media briefing describing ongoing operations in Afghanistan involving 20,000 United States troops). The United States may detain, for the duration of these hostilities, individuals legitimately determined to be Taliban combatants who “engaged in an armed conflict against the United States.” If the record establishes that United States troops are still involved in active combat in Afghanistan, those detentions are part of the exercise of “necessary and appropriate force,” and therefore are authorized by the AUMF.
Ex parte Milligan, 4 Wall. 2, 125 (1866), does not undermine our holding about the Government’s authority to seize enemy combatants, as we define that term today. In that case, the Court made repeated reference to the fact that its inquiry into whether the military tribunal had jurisdiction to try and punish Milligan turned in large part on the fact that Milligan was not a prisoner of war, but a resident of Indiana arrested while at home there. Id., at 118, 131. That fact was central to its conclusion. Had Milligan been captured while he was assisting Confederate soldiers by carrying a rifle against Union troops on a Confederate battlefield, the holding of the Court might well have been different. The Court’s repeated explanations that Milligan was not a prisoner of war suggest that had these different circumstances been present he could have been detained under military authority for the duration of the conflict, whether or not he was a citizen.1
Moreover, as Justice Scalia acknowledges, the Court in Ex parte Quirin, 317 U.S. 1 (1942), dismissed the language of Milligan that the petitioners had suggested prevented them from being subject to military process. Post, at 17—18 (dissenting opinion). Clear in this rejection was a disavowal of the New York State cases cited in Milligan, 4 Wall., at 128—129, on which Justice Scalia relies. See id., at 128—129. Both Smith v. Shaw, 12 Johns. *257 (N. Y. 1815), and M’Connell v. Hampton, 12 Johns. *234 (N. Y. 1815), were civil suits for false imprisonment. Even accepting that these cases once could have been viewed as standing for the sweeping proposition for which Justice Scalia cites them–that the military does not have authority to try an American citizen accused of spying against his country during wartime–Quirin makes undeniably clear that this is not the law today. Haupt, like the citizens in Smith and M’Connell, was accused of being a spy. The Court in Quirin found him “subject to trial and punishment by [a] military tribunal[ ]” for those acts, and held that his citizenship did not change this result. 317 U.S., at 31, 37—38.
Quirin was a unanimous opinion. It both postdates and clarifies Milligan, providing us with the most apposite precedent that we have on the question of whether citizens may be detained in such circumstances. Brushing aside such precedent–particularly when doing so gives rise to a host of new questions never dealt with by this Court–is unjustified and unwise.
To the extent that Justice Scalia accepts the precedential value of Quirin, he argues that it cannot guide our inquiry here because “[i]n Quirin it was uncontested that the petitioners were members of enemy forces,” while Hamdi challenges his classification as an enemy combatant. Post, at 19. But it is unclear why, in the paradigm outlined by Justice Scalia, such a concession should have any relevance. Justice Scalia envisions a system in which the only options are congressional suspension of the writ of habeas corpus or prosecution for treason or some other crime. Post, at 1. He does not explain how his historical analysis supports the addition of a third option–detention under some other process after concession of enemy-combatant status–or why a concession should carry any different effect than proof of enemy-combatant status in a proceeding that comports with due process. To be clear, our opinion only finds legislative authority to detain under the AUMF once it is sufficiently clear that the individual is, in fact, an enemy combatant; whether that is established by concession or by some other process that verifies this fact with sufficient certainty seems beside the point.