By Paul Reynolds
World affairs correspondent, BBC News website
Not closing: the maximum security wing at Guantanamo Bay
The statement by US Defence Secretary Robert Gates that Washington is "stuck" with Guantanamo Bay is a reflection of the mounting problems that the camp faces.
Mr Gates told a Senate committee that out of the 270 or so prisoners still there, about 50 to 70 were an "irreducible" minimum.
He said: "The problem is that either their home government won't
accept them or we're concerned that the home government will
let them loose once we return them home."
Some released prisoners, Mr Gates suggested, had returned to the battlefield. One is thought to have become a suicide bomber in Mosul in Iraq.
Yet these 50 to 70 prisoners could not be charged either, he said. This is presumably because there is not enough or no evidence against them.
The prospect for these prisoners therefore is indefinite detention, which raises its own legal and moral problems.
Eventual closure is the stated policy of the Bush administration, but one which looks like being missed in the remaining months of the presidential term. Human rights groups and other governments have for long argued for closure anyway.
"Gates is admitting they have a problem we all knew about," said Andy Worthington of the British group Reprieve, which monitors and offers legal advice to Guantanamo Bay prisoners.
"These are the 50-70 who have been cleared for release but who cannot be returned. They come from China, Uzbekistan, Tunisia, Libya and Algeria mainly.
"The US tried last year to agree memoranda of understanding with some countries, including Tunisia and two prisoners were sent back there. They have been jailed for three and seven years after an unsatisfactory trial. A US court has blocked a third return.
"Several Chinese Muslims picked up in Afghanistan were sent to Albania and all but one are thought to be there still. One has applied for asylum in Sweden."
Mr Worthington says there is another group that will also hold up any plans for closure. "This group is made up of prisoners who are regarded as too dangerous to release but against whom there is not sufficient evidence to justify a charge and trial by a military commission.
"But what kind of legal handbook does this come from? They face unlimited imprisonment."
The administration has also faced huge problems in starting the military commissions or tribunals that Congress has authorised.
The tribunals were supposed to be starting soon but the first two had to be put off after military judges ruled that the defendants had not been formally classified as "unlawful enemy combatants," as required by the law, and only as "enemy combatants."
One of those defendants was Osama Bin Laden's driver Salim Ahmed Hamdan. His trial has now been put off for another reason.
The US Supreme Court is due to rule by the end of June on whether prisoners at Guantanamo Bay have a constitutional right to habeas corpus, a procedure whereby a prisoner has to be brought to a court for justification of his detention. Until this issue is ruled upon, the military trials are unlikely to start.
Evidence and torture
There is also a question of evidence. One major al-Qaeda suspect Mohammed al-Qatani, one of six so-called "high-value" prisoners who were charged earlier this year, has had charges against him dropped.
It is thought this is because he was subject to what a military inquiry called "abusive" questioning, described as torture by his lawyer, at Guantanamo Bay and that his defence could move to have evidence based on these interrogations dismissed.
Mohammed al-Qatani is often referred to as the missing "2Oth hijacker" on 9/11, He was not allowed to enter the US on arrival at Orlando, where the hijackers' leader Mohammed Atta is thought to have been waiting to pick him up.
There have also been problems for the administration among the military prosecutors themselves, several of whom have resigned rather
than enforce the system of military tribunals.
One of them, Colonel Morris Davis, was chief prosecutor and he has stated that he did not want to use al-Qatani's alleged confessions as evidence because the prisoner had been abused. Col Davis claims that the senior legal officer for the commissions, Brigadier-General Thomas Hartmann clashed with him on this, though Brig Gen Hartmann denies that he discussed the issue of coerced confessions with Col Davis.
The upshot is that the system is in some doubt, not to say chaos.
However the administration is determined to try to press on with the remaining five "high-value" trials. The defendants include the alleged 9/11 mastermind Khalid Sheikh Mohammed.
He was subjected to waterboarding process but not at Guantanamo Bay , so it is possible that a trial could ignore that. There has been an effort to get subsequent "clean confessions" from these prisoners which could then be presented in court.
In more than one way, Guantanamo Bay continues in its legal limbo.