President Obama revived the Bush-era system of military tribunals for trials of suspected terrorists held at the Guantánamo Bay detention camp yesterday.

Although the White House emphasised that Mr Obama had never promised to scrap the bitterly criticised system of military commissions, his decision yesterday was markedly different to his rhetoric during the election campaign, when he suggested that detainees held at Guantánamo Bay should be dealt with through the federal courts. His decision risked another confrontation with many of his most fervent supporters on the liberal wing of the Democratic party.

Mr Obama drew swift condemnation from human rights groups increasingly angered by his reliance on legal tools or national security arguments inherited from the Bush administration. But he was praised by conservatives who have repeatedly warned that he is making America less safe.

The President tried to navigate a middle way through a highly partisan atmosphere by emphasising that he would reform the tribunals to make them fairer. “This is the best way to protect our country while upholding our deeply held values,” he said.

When, on his second day in office, Mr Obama halted all trials under the tribunal system and promised to close the camp within a year, he received adulatory headlines around the world for making a decisive break with his predecessor’s policy.

Since then, however, the Administration has discovered that shutting down Guantánamo is fraught with difficulty. It would like some of the remaining 240 inmates — those who represent no security threat — to be resettled abroad. Lakhdar Boumediene, a Bosnian who had been accused of involvement in a plot to bomb the US embassy in Sarajevo, was released yesterday to join relatives in France but US allies, including Britain, have resisted pressure to take more.

Other detainees, against whom there is overwhelming case for prosecution, will face trial in civilian courts. Mr Obama’s advisers, however, have concluded that this is not feasible for about 20 inmates, and it is these who will face revised versions of the military tribunals.

The advantages of such a system are that it helps prosecutors use classified information without compromising intelligence sources and convictions are less subject to lengthy appeals.

A third group of detainees, for whom there is not enough evidence to prosecute but who are deemed too dangerous to release, are likely to be incarcerated indefinitely without trial on the American mainland.

Some lawyers argue that they could be held under the international law of warfare, which allows governments to detain enemy fighters until the end of a conflict. Others say that the Administration would have to ask Congress to enact a law that would allow preventive detention, possibly through a new national security court.

Any such measure is certain to be opposed by the Left on civil liberties grounds and by Republicans who are already running advertisements suggesting that Mr Obama wants to bring dozens of terrorists on to the American mainland. The lack of a coherent proposal for closing Guantánamo led Congress to remove $80 million (£52 million) earmarked for this purpose from a war funding Bill on Thursday.

Military tribunals have already been subject to challenges from civil liberties groups who say that they deny defendants many of the rights that they would have in a civilian courtroom.

Mr Obama, who previously said that the system was flawed, tried to calm fears about reviving the military system by promising reforms “to restore the commissions as a legitimate forum for prosecution, while bringing them in line with the rule of law”.

These would limit the use of hearsay, ban evidence gained through cruel, inhuman or degrading treatment, give defendants more scope to pick their own lawyers and provide more protection if they do not testify.

“Military commissions have a long tradition in the United States. They are appropriate for trying enemies who violate the laws of war, provided that they are properly structured and administered,” Mr Obama said.

Pointing out that military commissions at Guantánamo had prosecuted only three suspected terrorists in more than seven years, he explained that his objection to the Bush policy had been based on it being ineffective.

Jonathan Hafetz, of the American Civil Liberties Union, said: “It’s disappointing that Obama is seeking to revive rather than end this failed experiment. Even with the proposed modifications, this will not cure the commissions or provide them with legitimacy. This is perpetuating the Bush administration’s misguided policy.”

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