The decisions will surely accelerate the shrivelling, if not the closure, of the detention camp on Cuba’s southeastern shore that has badly damaged the reputation of the US. They may prove to be some of the most significant rulings on the limits of presidential power in war since the Second World War. The rulings most directly affect the ten prisoners at Guantanamo who have been charged. It is hard to see how their trials, or “military commissions”, can go ahead. That would bring to an end the legal fantasy of the past six months, where the ten accused have been brought before chaotic pre-trial hearings, on the working premise that the Supreme Court would uphold the commissions. Defence, prosecution and judge, all in military uniform, have vied with one another to establish the ever-changing rules.

It is also hard to see how Air Force Colonel Morris Davis, the chief prosecutor, can charge another 65 inmates and bring them before the commissions, as he said last week that he would do if the court upheld them.

The court has not directly ruled on the principle of indefinite detention without charge for the 440 other prisoners at the camp. But that is also under sustained legal assault. The court’s decisions strengthen those cases.

The tone of the court’s rulings, as much as the detail, will add to the pressure on Bush to close the camp and bring the American imprisonment and trial of accused terrorists within conventional courts, either criminal or military. That does not mean that the US is bound to declare all the prisoners blameless and let them go. Some have already admitted offences. But the Administration has lost its case for keeping them outside the bounds of US or international law.

Some will say that this is the last reflex of a liberal-leaning Supreme Court and does not reflect the influence of Bush’s appointments. But even had Chief Justice John Roberts been able to vote, it would not have changed the result (he removed himself because he sat on an appeals court round of this case). That would, in any case, be a misreading of the tone of these judgments. They show a deep unease among the justices at Bush’s wide interpretation of the authority that Congress gave him after September 11 to fight the war against terrorism.

The justices seemed particularly aggrieved at the Administration’s claim that the Detainee Treatment Act, passed by Congress and signed into law by Bush last December, stripped federal courts of their jurisdiction over Guantanamo inmates.

This case took root two years ago in a pair of Supreme Court decisions that also curbed presidential powers. The court ruled that even though Guantanamo was not on US soil, Guanta- namo prisoners had the right to bring lawsuits in US courts. Lawyers promptly streamed on to the flights to Cuba. The lawyers for Salim Ahmed Hamdan, Osama bin Laden’s driver, do not dispute that a country at war has the right to remove those attacking it from the battlefield. But then, they argued, that person is a prisoner of war, protected by the Geneva Conventions, not an “unlawful combatant”, as the Administration has claimed.

Hamdan’s lawyers argued that if he were to be tried, it should be under the Uniform Code of Military Justice. That gives the accused the right to be present, to hear the evidence against him and to have that tested by a lawyer. Judges and jurors are strictly separated from the military command structure and there is an appeal to an independent court.

In contrast, at the Guanta- namo commissions, evidence may be unsworn written statements that cannot be tested in cross-examination. The accused may not be allowed to hear it if it is “classified”. The judge, as a senior military officer, can order the defence counsel to proceed against their client’s wishes. Any appeal is to the President.

In recent weeks the Administration has appeared more responsive to the hostility generated by Guantanamo. Tony Blair has called for the camp to close; so has Denmark, one of the closest allies of the US.

The Administration has struck deals with Saudi Arabia and Afghanistan to take back some of their citizens and has cut the prison population by about 30.

The recent suicides of three prisoners brought Guantanamo back into the headlines. But the passage of time alone was putting pressure on the US.

A move that some allies were prepared to overlook in the name of expediency, after September 11, looked, after 4½ years, like an unjustifiable breach of America’s own principles and laws. The court has added legal weight to that political force.

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