Rejecting Bush administration arguments, the US Supreme Court reversed course and agreed Friday to review whether Guantánamo Bay detainees can use the civilian court system to challenge their indefinite confinement.
The justices made the highly unusual reversal without comment along with other end-of-term orders.
In April, the court turned down an identical request, though two justices indicated they could be persuaded otherwise.
"Despite the obvious importance" of the cases, it would be premature to intervene, Justices John Paul Stevens and Anthony Kennedy wrote April 2 when the case was initially refused. At the time, three justices said they wanted to intervene immediately in the matter: Justices Stephen Breyer, Ruth Bader Ginsburg, and David Souter.
The court did not indicate what changed the justices' minds about considering the issue. But last week, lawyers for the detainees filed a statement from a military officer in which he described the inadequacy of the process the US military has been using for the past four years to classify the detainees as enemy combatants.
The Bush administration says that a new law strips civilian courts of their jurisdiction to hear detainee cases.
The move to grant a motion for rehearing in a previously denied case is rare. Court observers pointed to a 1968 case as the closest parallel to what happened Friday.
Five of the nine justices must agree to take a case that previously has been denied a hearing, according to an authoritative text on the Supreme Court.
"This is a stunning victory for the detainees," said Eric Freedman, professor of constitutional law at Hofstra Law School, who has been advising inmates at the US prison in Guantánomo Bay, Cuba. "It goes well beyond what we asked for and clearly indicates the unease up there" at the Supreme Court.
Gordon Johndroe, a spokesman for the National Security Council, said: "We did not think that court review at this time was necessary, but we are confident in our legal position."
The case is expected to be heard in the fall.
In February, the US Circuit Court of Appeals for the District of Columbia upheld a key provision of a law the Bush administration pushed through Congress last year stripping federal courts of their ability to hear the detainees' challenges to their confinement.
On April 2, the Supreme denied the detainees' request to review the February appeals court ruling. The detainees then petitioned the court to reconsider its denial.
Dismissing the petitions would be "a profound deprivation" of the prisoners' right to speedy court review, lawyers for the detainees said.
The administration asked that the detainees' Supreme Court petitions be thrown out.
Many of the 375 detainees have been held at Guantánamo for five years.
In recent months, the main arena in the legal battle over the detainees has been the US Circuit Court of Appeals for the District of Columbia.
The appeals court is considering how to handle the detainees' challenges to tribunals that found them to be enemy combatants, leaving them without any of the legal rights accorded prisoners of war.
The detainees' attorneys want the appeals court to allow a broad inquiry questioning the accuracy and completeness of the evidence the Combatant Status Review Tribunals (CSRTs) gathered about the detainees, most of it classified.
The Justice Department has been seeking a limited review, saying that the findings of the military tribunals are "entitled to the highest level of deference."
An Army reserve officer and lawyer who played a key role in the enemy combatant hearings at Guantánamo Bay says tribunal members relied on vague and incomplete intelligence while being pressured to rule against detainees, often without any specific evidence. The officer's affidavit, submitted to the Supreme Court last Friday, is the first criticism by a member of the military panels that determine whether detainees will continue to be held.
"I suspect that the disclosure about the corrupted CSRT proceedings and the very restrictive government view of what the detainees can do in the lower courts led the justices to conclude that they should take up these issues," said Washington attorney David Remes. Mr. Remes represents 18 detainees. "The court's decision to hear the cases brings the detainees one step closer to receiving their day in court."
The operation of Guantánamo Bay has brought widespread criticism abroad of the Bush administration and condemnation from Democrats in Congress.