They were called the "worst of the worst," hardened terrorists and crazed Islamic jihadists who were shackled, hooded and airlifted to be imprisoned in this Caribbean gulag created by the Bush administration.
Nearly nine years later, the billion-dollar prison complex stands mostly empty. Only about 170 detainees remain. Hundreds have been quietly released, and scores more are cleared but have no where to go.
Only four have gone through the widely discredited war-crimes tribunal process: Osama bin Laden's driver; a bodyguard; his propaganda chief; and an Australian sheep-shearer who embraced Islam and got picked up in Afghanistan.
The fifth will be Omar Khadr, the only Canadian, only child soldier and only detainee charged with battlefield homicide in the killing a U.S. soldier.
For years, Mr. Khadr's long-delayed trial was heralded as a key case to test the legality of Washington's effort to charge a teenager with war crimes despite international conventions outlawing trials of child soldiers.
The case seems about to end, short of its billing, with a plea-bargained deal. The now burly, bearded 24-year-old is expected to plead guilty Monday as part of a deal that leads, eventually, to his return to Canada.
"There is no justice here," said Dennis Edney, the outspoken Canadian lawyer who is part of Mr. Khadr's defence team, adding Mr. Khadr faces a grim choice. "He either pleads guilty to avoid trial or he goes to trial and the trial is an unfair process."
As part of any deal, Mr. Khadr will be required to publicly confess to the terrorism and murder charges.
He has apparently ditched his vow never to admit to tossing the grenade that killed a Sergeant Christopher Speer during a fierce, four-hour firefight at an Afghan compound in July, 2002.
The son of a prominent al-Qaeda financier, he was the grievously wounded sole survivor among those in the compound. He was detained at age 15.
Mr. Khadr will also agree to a long list of facts hammered out in the deal. That will set the stage for a relatively short sentencing phase in which both prosecutors and defence teams will present testimony from mental-health experts.
Also expected to testify in the heavily fortified courtroom will be Tabitha Speer, the widow of Sgt. Speer.
A guilty plea would launch a new phase of Mr. Khadr's life. He would not return to the open, communal living in Camp Four where he has lived for years with dozens of the more compliant detainees who have the most privileges at Guantanamo.
Instead, as a convicted war criminal, he would be imprisoned in Camp Five, a hulking copy of a $150-million Michigan prison, with a cell of his own in a wing with only two other occupants.
Instead of the soccer matches and video games he currently enjoys, Mr. Khadr's would live in near-solitary confinement.
The only other convicted detainees at Guantanamo are Ali Hamza Bahlul, an intemperate ideologue shunned by other detainees and serving a life sentence, and Ibrahim Qosi, a 50-year-old former cook due to be released within a in a year.
"Omar has to give up the only society he has ever known as an adult" for the duration of his Guantanamo sentence, said a source close to the defence team who is still worried that the unpredictable Mr. Khadr could balk at the penultimate moment and refuse the deal.
That would force the Obama administration to proceed with a full-blown trial amid renewed allegations of confessions extracted by torture and the threat of being gang-raped to death unless he co-operated with interrogators.
Unlike Britain and Australia, who demanded the repatriation from Guantanamo of their citizens, the Canadian government has a long-standing refusal to intervene on Mr. Khadr's behalf, which Mr. Edney scornfully derided.
Ottawa sent a pair of sunglasses to protect Mr. Khadr's sole remaining, but damaged, eye, two months ago, Mr. Edney said. It's the only thing the government has ever done for Omar, he added.