My current favourite bits from the decision [emphases added]:

A brief account of the writ’s history and origins shows that protection for the habeas privilege was one of the few safeguards of liberty specified in a Constitution that, at the outset, had no Bill of Rights; in the system the Framers conceived, the writ has a centrality that must inform proper interpretation of the Suspension Clause. That the Framers considered the writ a vital instrument for the protection of individual liberty is evident from the care taken in the Suspension Clause to specify the limited grounds for its suspension: The writ may be suspended only when public safety requires it in times of rebellion or invasion. The Clause is designed to protect against cyclical abuses of the writ by the Executive and Legislative Branches. It protects detainee rights by a means consistent with the Constitution’s essential design, ensuring that, except during periods of formal suspension, the Judiciary will have a time-tested device, the writ, to maintain the “delicate balance of governance.” Hamdi, supra, at 536. Separation-of-powers principles, and the history that influenced their design, inform the Clause’s reach and purpose.

 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, not this Court, say “what the law is.” 

At the CSRT stage the detainee has limited means to find or present evidence to challenge the Government’s case, does not have the assistance of counsel, and may not be aware of the most critical allegations that the Government relied upon to order his detention. His opportunity to confront witnesses is likely to be more theoretical than real, given that there are no limits on the admission of hearsay. The Court therefore agrees with petitioners that there is considerable risk of error in the tribunal’s findings of fact. And given that the consequence of error may be detention for the duration of hostilities that may last a generation or more, the risk is too significant to ignore. Accordingly, for the habeas writ, or its substitute, to function as an effective and meaningful remedy in this context, the court conducting the collateral proceeding must have some ability to correct any errors, to assess the sufficiency of the Government’s evidence, and to admit and consider relevant exculpatory evidence that was not introduced during the earlier proceeding.

 Petitioners have met their burden of establishing that the DTA review process is, on its face, an inadequate substitute for habeas. Among the constitutional infirmities from which the DTA potentially suffers are the absence of provisions allowing petitioners to challenge the  President’s authority under the AUMF to detain them indefinitely, to contest the CSRT’s findings of fact, to supplement the record on review with exculpatory evidence discovered after the CSRT proceedings, and to request release. The statute cannot be read to contain each of these constitutionally required procedures. MCA §7 thus effects an unconstitutional suspension of the writ. 

Petitioners need not seek review of their CSRT determinations in the D. C. Circuit before proceeding with their habeas actions in the District Court. If these cases involved detainees held for only a short time while awaiting their CSRT determinations, or were it probable that the Court of Appeals could complete a prompt review of their applications, the case for requiring temporary abstention or exhaustion of alternative remedies would be much stronger. But these qualifications no longer pertain here. In some instances six years have elapsed without the judicial oversight that habeas corpus or an adequate substitute demands. To require these detainees to pursue the limited structure of DTA review before proceeding with habeas actions would be to require additional months, if not years, of delay. This holding should not be read to imply that a habeas court should intervene the moment an enemy combatant steps foot in a territory where the writ runs. Except in cases of undue delay, such as the present, federal courts should refrain from entertaining an enemy combatant’s habeas petition at least until after the CSRT has had a chance to review his status. 

In considering both the procedural and substantive standards used to impose detention to prevent acts of terrorism, the courts must accord proper deference to the political branches. However, security subsists, too, in fidelity to freedom’s first principles, chief among them being freedom from arbitrary and unlawful restraint and the personal liberty that is secured by adherence to the separation of powers. 

See The Suspension Clause: English Text, Imperial Contexts and American Implications, Halliday & White, SSRN [pdf]

Update:  I’m watching a former Reagan and H.W. Bush official, David Rivkin, freak out on the Lehrer News Hour about the “reach” of the SCOTUS decision, saying things like the purview the US Constitution has now been extended so that it can be bestowed upon foreign citizens at places like Basrah Airport.  Yeah, the US really has complete control over Iraq, like they do at Guantanamo.  As long as the US is successful in its game of trying to make it look like the Iraq government is in control, even as the US is busy trying to blackmail them into agreeing to its security deal while keeping Iraqi money hostage in America, Iraqis are not going to be entitled to the privileges extended by the US Constitution.  On the other hand, I’d love to try the argument …

And with respect to the sovereignty issue, Ok guys, so who DOES have control over Guantanamo?  Cuba?  Fine.  Let the Cubans determine the fate of the detainees.

It’s so hard to watch these slippery slope geeks try to make Americans frightened of their “left wing” Supremes.  I hate it.  This is really a pretty conservative judgement.  Anyone who disgrees, tell me exactly how and why.  The trials at Gitmo will go on.  And the day that an American court releases a detainee as the result of a writ of habeas corpus will be a day to celebrate.  But the real celebration will be a lot longer coming.  Gitmo will be gone, most of the detainees will be repatriated or afforded refugee status in a safe place, the US will be out of Iraq and so will Blackwater … sigh.  That will be some celebration and I won’t live to see it.