How did SCOTUS ultimately rule?
Hamdi v. Rumsfeld, 542 US 507 (2004)
That the government's detention of Hamdi violated his due process rights. Hamdi is a US citizen held as an enemy combatant. Lots of issues wrapped up in the case, and the "remedy" prescibed by the court includes somewhat indefinite forward-looking aspects, for example,
There remains the possibility that the standards we have articulated could be met by an appropriately authorized and properly constituted military tribunal. Indeed, it is notable that military regulations already provide for such process in related instances, dictating that tribunals be made available to determine the status of enemy detainees who assert prisoner-of-war status under the Geneva Convention.
Scalia's dissent concisely illustrates some of the alternative venues and remedies, that is, military v. civilian; citizen v. non-citizen; trial for treason v. detention until hostilities are over. It's opening reads as follows:
Justice Scalia, with whom Justice Stevens joins, dissenting.Petitioner, a presumed American citizen, has been imprisoned without charge or hearing in the Norfolk and Charleston Naval Brigs for more than two years, on the allegation that he is an enemy combatant who bore arms against his country for the Taliban. His father claims to the contrary, that he is an inexperienced aid worker caught in the wrong place at the wrong time. This case brings into conflict the competing demands of national security and our citizens' constitutional right to personal liberty. Although I share the Court's evident unease as it seeks to reconcile the two, I do not agree with its resolution.
Where the Government accuses a citizen of waging war against it, our constitutional tradition has been to prosecute him in federal court for treason or some other crime. Where the exigencies of war prevent that, the Constitution's Suspension Clause, Art. I, §9, cl. 2, allows Congress to relax the usual protections temporarily. Absent suspension, however, the Executive's assertion of military exigency has not been thought sufficient to permit detention without charge. No one contends that the congressional Authorization for Use of Military Force, on which the Government relies to justify its actions here, is an implementation of the Suspension Clause. Accordingly, I would reverse the decision below.