The court’s action, which had been urged by the Obama administration, wiped away one of the Bush administration’s greatest victories in the lower courts, a 2008 ruling that expanded the limits of executive authority to combat terrorism by allowing such detentions.
But the one-paragraph Supreme Court ruling leaves open the question of whether the military detention of legal residents as enemy combatants can ever be constitutional. The ruling came in the case of Ali Saleh Kahlah al-Marri, a citizen of Qatar who was lawfully in the United States as a student when he was arrested in 2001. The court, which had agreed to hear Mr. Marri’s challenge to his detention in December, said it would not hear the case after all in light of his indictment last week on criminal charges in federal court.
More significantly, the court erased the lower-court ruling in the case, al-Marri v. Spagone, 08-368. Last year, in a fractured decision, the United States Court of Appeals for the Fourth Circuit, in Richmond, Va., said the president had the legal authority to detain Mr. Marri, subject to a court hearing on whether he was properly designated an enemy combatant.
The American Civil Liberties Union, which represents Mr. Marri, had hoped the Supreme Court would consider his case even after his indictment. But Jonathan Hafetz, a lawyer for Mr. Marri, expressed satisfaction with the justices’ decision to undo the Fourth Circuit ruling.
“The fact that the government did not defend its previously claimed detention power and that the Supreme Court wiped out the legally bankrupt lower-court ruling,” Mr. Hafetz said, “should make clear that in the United States no president can imprison legal residents or American citizens without charges or trial by calling them ‘enemy combatants.’ ”
While the government did not defend its power to detain Mr. Marri at present, it left open the possibility that he or others might be subject to military detention as enemy combatants in the future. “Any future detention — were that hypothetical possibility ever to occur — would require new consideration under then-existing circumstances and procedure,” the Justice Department told the court in a brief filed Wednesday.
The government did take pains to deny that it was manipulating the legal system, an accusation made against the Bush administration when it moved Jose Padilla from military detention to criminal court in 2007.
“The government’s agreement here that vacatur of the decision below would be appropriate,” the brief said, “conclusively demonstrates that the government is not attempting to preserve its victory while evading review.”
In Mr. Padilla’s case, the lower-court decision had been left intact. In that case, the Fourth Circuit upheld the detention of Mr. Padilla, an American citizen, though its ruling mostly focused on his activities on the battlefield in Afghanistan.
The Supreme Court has said Congress granted the president the power to detain at least those enemy combatants captured on the battlefield in Afghanistan, even if they were American citizens, for the duration of hostilities there.
The government has said Mr. Marri is a sleeper agent of Al Qaeda. But it has not come forward with evidence to back up that assertion, a burden it will now face in federal court.