Long-awaited US moves to close the controversial detention center at Guantanamo Bay for "war on terror" suspects will run into an array of complex procedural and legal pitfalls, analysts say.
About 245 prisoners are still held at the jail housed at a US naval base in southern Cuba, which has been a rallying point for anti-American sentiment around the world for the last eight years.
President Barack Obama on Thursday signed an executive order to close the prison within a year, and pledged to sift through the evidence and determine why the detainees are still being held in the next six months.
To carry out this huge task, a review board co-chaired by the Justice Department and the Pentagon, among other agencies, will be charged with assessing individual cases.
The inmates are likely to fall into three categories. First those for whom the US has said it has no evidence of wrong-doing, will be transfered and subsequently released.
The second group of detainees will be prosecuted according to the evidence held by the government.
The third and most troubling group for the Obama administration are those deemed too dangerous for release, but against whom the government has either not enough credible evidence or only unusable confessions obtained through "enhanced" interrogation -- or torture, as some charge.
For this group the review board may seek legal means to keep them in detention, perhaps indefinitely.
Obama's Guantanamo decree this week lays out "a process and an aspiration," but it carefully "keeps all options on the table and gives the new administration wide latitude to make policy as it learns over the coming year exactly whom it is dealing with," according to Brookings Institution fellow and research director Benjamin Wittes.
Civil liberties and human rights associations, along with a number of legal groups, have argued that indefinite detention without charge is unjustifiable, even if there is suspicion of a future danger from a released detainee.
The revelation Friday that two former detainees at Guantanamo have been elevated to the senior ranks of Al-Qaeda is set to heighten debate over whether to keep allegedly dangerous prisoners locked-up.
In another complication, the US Supreme Court ruled in June that detainees can challenge their detention in US federal courts in Washington, meaning that different legal reviews of Guantanamo cases may take place in parallel.
Since June, six inmates have been found to have been illegally detained.
Hours after Obama's inauguration on Tuesday, the new administration requested a postponement of legal hearings in three cases, but in such cases "the detainee's lawyer can either consent to or oppose such a request," said David Cynamon, a lawyer representing four Kuwaiti detainees.
"It would then be up to the court to decide whether to grant a delay in each such case," he added.
Questions surrounding where to transfer the prisoners to if they are to remain in detention are also far from being resolved.
Democrats and Republicans alike have made it clear they would not like "terrorists," who were perhaps behind the September 11 attacks, to be held in prisons in their state or district.
Likewise in Europe, where some inmates could be transferred, the issue remains a flashpoint for heated debate.
One of the profound unanswerable questions facing detainees is not whether they will reach a day in court, but whether that court will be federal one, or a military commission.
In a commission the top secret nature of the evidence held against some detainees creates unique challenges for the US justice system.
In some cases the inmates, and in some cases their lawyers, are trapped in a judicial web akin to a Franz Kafka novel, where they are unable to hear or challenge evidence brought against them.
Ill-treatment of the detainees could present difficulties for which court the inmates will eventually see.
Major Jon S. Jackson, who represents alleged September 11 plotter Mustapha al-Hawsawi, says military commissions may be the only course of trying some key Guantanamo detainees.
"It is very important to ask why we are in the military commissions system. One answer is because of what we have done to these individuals," he said.