The U.S. Supreme Court on Thursday strongly limited the power of the Bush administration to conduct military tribunals for suspected terrorists imprisoned at the U.S. Navy base in Guantanamo Bay, Cuba.
The 5-3 ruling means officials will have to come up with a new policy to prosecute at least 10 so-called "enemy combatants" awaiting trial -- it does not address the government's right to detain suspects.
The case was a major test of Bush's authority as commander-in-chief during war. Bush has aggressively asserted the power of the government to capture, detain, and prosecute suspected terrorists in the wake of the 9/11 attacks.
At the center of the dispute was a Yemeni man, Salim Ahmed Hamdan, who was al Qaeda leader Osama bin Laden's driver and bodyguard.
"The military commission at issue is not expressly authorized by any congressional act," said Justice John Paul Stevens, writing for the majority. The tribunals, he said, "must be understood to incorporate at least the barest of those trial protections that have been recognized by customary international law."
"In undertaking to try Hamdan and subject him to criminal punishment, the executive (Bush) is bound to comply with the rule of law that prevails in this jurisdiction," Stevens said.
Dissenting were justices Antonin Scalia, Clarence Thomas and Samuel Alito. Scalia, in his dissenting opinion, used the word "mess" to describe the court's reasoning.
"The president's decision to try Hamdan before a military commission for his involvement with al Qaeda is entitled to a heavy measure of deference," said Thomas.
"It seems clear that the commissions at issue here meet the standard" established by the government to try the accused terrorists, Alito wrote.
Chief Justice John Roberts did participate in the case because he ruled on the case, in favor of the government, at the appellate level.
Hamdan's lawyers argued that Bush exceeded his authority by setting up military commissions to try terrorist suspects, whom the administration terms "enemy combatants," rather than prisoners of war.
The administration's position was that the term means detainees do not have the rights traditionally afforded prisoners of war, as outlined in the Geneva Conventions.
The enemy combatant designation, according to the Bush administration, means the suspect can be held without charges in a military prison without the protections of the U.S. criminal justice system, such as the right to counsel -- a status the court rejected.
The Guantanamo Bay facility opened in 2002 and holds about 460 men suspected of links to al Qaeda and the Taliban.
President Bush on Wednesday said he was considering shutting the facility, and would decide after the court ruled. "I'd like to end Gitmo, like it to be over with," he said at a European Union summit in Vienna.
"One of the things we will do is that we will send people back to their home countries. We have about 400 people left; 200 have been sent back. There are some who need to be tried in U.S. courts," Bush said. "They are cold-blooded killers. They will murder somebody if they are let out on the street. And yet we believe there ought to be a way forward in the court of law."
Many world leaders have pressured Bush to close the camp.
Late last year, Congress passed and President Bush signed the Detainee Treatment Act, which ostensibly limited court intervention over the prisoner issue.
Hamdan's attorney, Neal Katyal, told the justices, "If you adopt the government's reading here, they have said they want to try 75 military commission cases or so in the first wave, you will then be left with 75 trials that take place without even the most basic question of what the parameters are that these commissions are operating under."