The victory may be only temporary, however. The high court twice previously has extended legal protections to prisoners at the U.S. naval base in Cuba. These individuals were seized as potential terrorists following the Sept. 11, 2001, attacks and only 10 have been charged with a crime.

Despite the earlier rulings, none of the roughly 385 detainees has yet had a hearing in a civilian court challenging his detention because the administration has moved aggressively to limit the legal rights of prisoners it has labeled as enemy combatants.

A federal appeals court in Washington in February upheld a key provision of a law enacted last year that strips federal courts of their ability to hear such challenges.

At issue is whether prisoners held at Guantánamo have a right to habeas corpus review, a basic tenet of the Constitution that protects people from unlawful imprisonment.