In a stinging rebuke to president George Bush's conduct of the fight against terrorism, the US Supreme Court has ruled that military tribunals used to try inmates at Guantánamo Bay violate American law and the Geneva Conventions.
In a 5-3 decision, the court ruled that the trials were not authorised by Congress and their structure and procedures violated the Uniform Code of Military Justice, which governs the US military and international laws on the treatment of prisoners of war.
Mr Bush said he would consult Congress on how to respond to the ruling, which represents a sweeping rejection of the administration's approach to the handling of suspects picked up after September 11th.
"We will seriously look at the findings, obviously. And one thing I'm not going to do, though, is I'm not going to jeopardise the safety of the American people. People have got to understand that. I understand we're in a war on terror; that these people were picked up off of a battlefield; and I will protect the people and, at the same time, conform with the findings of the Supreme Court," Mr Bush said.
The court ruling did not order the closure of the Guantánamo Bay detention centre, where 450 people are held. It upheld an appeal by Salim Ahmed Hamdan (36), a Yemeni who has admitted acting as Osama bin Laden's driver, against the Bush administration's attempt to try him before a military tribunal set up expressly to hear Guantánamo cases.
The court found the military tribunal was illegally set up without congressional approval and that it denied the defendant basic rights, including the right to hear all evidence against him and to be present at his trial. The Bush administration claimed the president's war powers entitled him to set up the military tribunal and that a law passed by Congress late last year meant the Supreme Court was not entitled to hear Mr Hamdan's case.
The court rejected both arguments, although the three most conservative justices - Antonin Scalia, Clarence Thomas and Samuel Alito - dissented from the decision.
Mr Thomas said the court's willingness "to second-guess the determination of the political branches that these conspirators must be brought to justice is both unprecedented and dangerous".
Justice Stephen Breyer disputed that assertion and said the president had overstepped his authority.
"The court's conclusion ultimately rests upon a single ground: Congress has not issued the executive a 'blank cheque'. Indeed, Congress has denied the president the legislative authority to create military commissions of the kind at issue here. Nothing prevents the president from returning to Congress to seek the authority he believes necessary," Mr Breyer wrote.
Cmdr Charles Swift, the Navy lawyer assigned by the military to represent Mr Hamdan, said the logical next step would be for Mr Hamdan to be tried either by a traditional military court martial, as provided for under the Geneva Convention, or by a federal court and that yesterday's judgment marked "a return to our fundamental values".
"That return marks a high-water point. It shows we can't be scared out of who we are, and that's a victory," he said.
Human rights groups welcomed the ruling, which Amnesty International described as a victory for the rule of law and human rights.
"The US administration should ensure that those held in Guantánamo should be either released or brought before civilian courts on the US mainland," it said.
Senate majority leader Bill Frist said he would move quickly to introduce legislation authorising military tribunals to try Guantánamo inmates.
"To keep America safe in the war on terror, I believe we should try terrorists only before military commissions, not in our civilian courts. In response to today's Supreme Court decision, Congress should work with the president to update our laws on terrorist combatants to respond to the new threats of a post-9/11 world. Since this issue so directly impacts our national security, I will pursue the earliest possible action in the United States Senate," he said.
Mr Bush has said repeatedly in recent weeks that he would like to close the Guantánamo detention centre and to repatriate some prisoners and put others on trial.