Washington ? A sharply divided Supreme Court ruled Thursday that Guantanamo Bay detainees can challenge their extended imprisonment in federal court, and struck down as inadequate an alternative review system that Congress set up.

Repudiating a key tenet of the Bush administration’s war-on-terrorism policy, the court’s 5-4 majority concluded that foreigners held at the U.S. naval base at Guantanamo Bay, Cuba, retain the same rights as U.S. residents to seek writs of habeas corpus. The landmark ruling will permit several hundred accused enemy combatants to see the evidence that justifies their captivity.

The long-awaited ruling in the combined cases known as Boumediene v. Bush and Al-Odah v. United States is the latest in a string of judicial defeats for the Bush administration. It marks the third time in four years that the Supreme Court has repudiated the administration’s efforts to exclude foreign prisoners from traditional legal protections.

The ruling covers some 270 men currently held at Guantanamo. It doesn’t directly address the 20 or so men who now are facing trials before separate military commissions.

“It’s been a long struggle,” said Michael Ratner, the president of the Center for Constitutional Rights, which filed the first lawsuits challenging the detentions.