(i)
The Court does not question the Government’s position thatCuba maintains sovereignty, in the legal and technical sense, over Guantanamo, but it does not accept the Government’s premise that de jure sovereignty is the touchstone of habeas jurisdiction. Common-
law habeas’ history provides scant support for this proposition,and it is inconsistent with the Court’s precedents and contrary tofundamental separation-of-powers principles. Pp. 22–25.
(ii)
Discussions of the Constitution’s extraterritorial application
in cases involving provisions other than the Suspension Clauseundermine the Government’s argument. Fundamental questions regarding
the Constitution’s geographic scope first arose when the Nation
acquired Hawaii and the noncontiguous Territories ceded bySpain after the Spanish-American War, and Congress discontinued its prior practice of extending constitutional rights to territories by statute. In the so-called Insular Cases, the Court held that the Constitution
had independent force in the territories that was not contingent
upon acts of legislative grace. See, e.g., Dorr v. United States, 195 U. S. 138. Yet because of the difficulties and disruption inherentin transforming the former Spanish colonies’ civil-law system into an Anglo-American system, the Court adopted the doctrine of territorialincorporation, under which the Constitution applies in full in incorporated
Territories surely destined for statehood but only in part inunincorporated Territories. See, e.g., id., at 143. Practical considerations
likewise influenced the Court’s analysis in Reid v. Covert, 354
U.
S. 1, where, in applying the jury provisions of the Fifth and Sixth Amendments to American civilians being tried by the U. S. militaryabroad, both the plurality and the concurrences noted the relevance of practical considerations, related not to the petitioners’ citizenship,but to the place of their confinement and trial. Finally, in holdingthat habeas jurisdiction did not extend to enemy aliens, convicted of violating the laws of war, who were detained in a German prison during
the Allied Powers’ post-World War II occupation, the Court, in Johnson v. Eisentrager, 339 U. S. 763, stressed the practical difficulties
of ordering the production of the prisoners, id., at 779. The Government’s
reading of Eisentrager as adopting a formalistic test for determining
the Suspension Clause’s reach is rejected because: (1) the

discussion of practical considerations in that case was integral to apart of the Court’s opinion that came before it announced its holding, see id., at 781; (2) it mentioned the concept of territorial sovereigntyonly twice in its opinion, in contrast to its significant discussion ofpractical barriers to the running of the writ; and (3) if the Government’s
reading were correct, the opinion would have marked not only a change in, but a complete repudiation of, the Insular Cases’ (andlater Reid’s) functional approach. A constricted reading of Eisentrager
overlooks what the Court sees as a common thread uniting all these cases: The idea that extraterritoriality questions turn on objective
factors and practical concerns, not formalism. Pp. 25–34.
(iii) The Government’s sovereignty-based test raises troubling separation-of-powers concerns, which are illustrated by Guantanamo’s
political history. Although the United States has maintained
complete and uninterrupted control of Guantanamo for over 100 years, the Government’s view is that the Constitution has no effect
there, at least as to noncitizens, because the United States disclaimed
formal sovereignty in its 1903 lease with Cuba. The Nation’s basic charter cannot be contracted away like this. The Constitution grants Congress and the President the power to acquire, dispose of,and govern territory, not the power to decide when and where its terms apply. To hold that the political branches may switch the Constitution
on or off at will would lead to a regime in which they, notthis Court, say “what the law is.” Marbury v. Madison, 1 Cranch 137, 177. These concerns have particular bearing upon the Suspension
Clause question here, for the habeas writ is itself an indispensable
mechanism for monitoring the separation of powers. Pp. 34–36.
(iv) Based on Eisentrager, supra, at 777, and the Court’s reasoning
in its other extraterritoriality opinions, at least three factors are relevant in determining the Suspension Clause’s reach: (1) thedetainees’ citizenship and status and the adequacy of the process through which that status was determined; (2) the nature of the sites where apprehension and then detention took place; and (3) the practical
obstacles inherent in resolving the prisoner’s entitlement to thewrit. Application of this framework reveals, first, that petitioners’status is in dispute: They are not American citizens, but deny theyare enemy combatants; and although they have been afforded someprocess in CSRT proceedings, there has been no Eisentrager–style trial by military commission for violations of the laws of war. Second, while the sites of petitioners’ apprehension and detention weigh against finding they have Suspension Clause rights, there are critical differences between Eisentrager’s German prison, circa 1950, and theGuantanamo Naval Station in 2008, given the Government’s absoluteand indefinite control over the naval station. Third, although the

Court is sensitive to the financial and administrative costs of holdingthe Suspension Clause applicable in a case of military detention abroad, these factors are not dispositive because the Government presents no credible arguments that the military mission at Guantanamo
would be compromised if habeas courts had jurisdiction. The situation in Eisentrager was far different, given the historical context and nature of the military’s mission in post-War Germany. Pp. 36–
41.
(d)
Petitioners are therefore entitled to the habeas privilege, and if that privilege is to be denied them, Congress must act in accordance
with the Suspension Clause’s requirements. Cf. Rasul, 542
U.
S., at 564. Pp. 41–42.
3. Because the DTA’s procedures for reviewing detainees’ statusare not an adequate and effective substitute for the habeas writ,MCA §7 operates as an unconstitutional suspension of the writ. Pp.42–64.
(a) Given its holding that the writ does not run to petitioners, the
D. C. Circuit found it unnecessary to consider whether there was anadequate substitute for habeas. This Court usually remands for consideration
of questions not decided below, but departure from this rule is appropriate in “exceptional” circumstances, see, e.g., Cooper Industries, Inc. v. Aviall Services, Inc., 543 U. S. 157, 169, here, the grave separation-of-powers issues raised by these cases and the fact that petitioners have been denied meaningful access to a judicial forum
for years. Pp. 42–44.
(b) Historically, Congress has taken care to avoid suspensions ofthe writ. For example, the statutes at issue in the Court’s two leading
cases addressing habeas substitutes, Swain v. Pressley, 430 U. S. 372, and United States v. Hayman, 342 U. S. 205, were attempts tostreamline habeas relief, not to cut it back. Those cases provide little guidance here because, inter alia, the statutes in question gave thecourts broad remedial powers to secure the historic office of the writ, and included saving clauses to preserve habeas review as an avenueof last resort. In contrast, Congress intended the DTA and the MCA to circumscribe habeas review, as is evident from the unequivocal nature
of MCA §7’s jurisdiction-stripping language, from the DTA’s text limiting the Court of Appeals’ jurisdiction to assessing whether the CSRT complied with the “standards and procedures specified by theSecretary of Defense,” DTA §1005(e)(2)(C), and from the absence of a saving clause in either Act....