Less than six months before his self-imposed deadline to shut down Guantanamo, US President Barack Obama faces key fights over where to move detainees and how to prosecute them.
His administration has only had limited success in emptying the detention center of those considered its most low-risk inmates, sending them home or to third countries willing to provide them with asylum.
Portugal this week joined Bermuda, France, Ireland, and even the Pacific archipelago of Palau in agreeing to accept detainees from the prison, located on a US naval base at Guantanamo Bay, Cuba.
Obama is still wrestling with what to do with some 229 detainees who remain, among them the highest-profile arrests in his predecessor George W. Bush’s "war on terror" including Khalid Sheikh Mohammed, the self-described mastermind of the September 11, 2001 attacks.
Obama made shutting the camp — a symbol for many of all that was wrong with Bush’s "war on terror" — by the end of his first year in office on January 2010 a major campaign pledge.
But his decision earlier this year to prosecute some detainees in reformed versions of the Bush-era military commissions and try others in federal courts has met with growing opposition.
Human rights groups say commissions commute detainees’ legal rights and remain unconvinced by the Obama administration’s promise to refer as many cases as possible to civilian courts.
A group of senators, including Republicans Lindsey Graham and John McCain, Independent Joe Lieberman and Democrat Jim Webb, released a letter on Thursday calling on the administration to avoid using federal civilian courts at all.
"Given the robust procedural and substantive rights now provided by this revised system of military commissions and the sensitive nature of much of the evidence that would be brought forth, we are disturbed that your administration has expressed a clear preference for… federal district courts," they wrote.
"We strongly believe that it would be unwise to try alleged war criminals in civilian communities with civilian juries, as do a significant majority of our colleagues."
The administration has promised to reform the much-criticized military commission system, which was overhauled in 2006 after a Supreme Court ruling.
The reshaped tribunals, overseen by a military judge and jury, will allow detainees to pick their own lawyers, and will have tougher rules on the use of hearsay — evidence from a witness who did not learn it firsthand.
The administration has also pledged to ban the use of evidence obtained though "cruel, inhumane and degrading treatment."
The proposed reforms do not go far enough for some, with Sarah Mendelsohn of the Center for Strategic and International Studies pointing out that "they are not going to put a US citizen through the military commissions."
Mendelsohn and others note that the military commissions at Guantanamo have prosecuted fewer than five detainees in the same time that US federal courts have convicted over 100 terror suspects.
"This conversation is constantly missing the empirical fact that military commissions have not done a good job at handling terrorist cases," Mendelsohn told AFP.
Democratic Senator Dick Durbin points to the record of civilian courts in handling terror cases.
"From 9/11 to the end of 2007, 145 terrorists have been convicted and sentenced for their crimes," he said. "In just the last five months, since January 1, 2009, more than 30 terrorists have been successfully prosecuted."
Defense lawyers for some of the detainees also question the jurisdiction of the military tribunals, which have not been used in the United States since World War Two, and are traditionally a forum to prosecute war crimes.
"We are not dealing with law of war offenses," said Major David Frakt, a military defense lawyer for Afghan detainee Mohamed Jawad, who has been ordered released from Guantanamo by a federal court.
Frakt argues that many of the allegations against detainees stem from acts that occurred before 9/11, when the United States was not at war.
Obama also faces opposition to the transfer of detainees into the United States, with two Kansas senators this week threatening to hold up votes on administration nominees after reports of possible transfers to a Kansas military prison.
"Enemy combatants should under no circumstances be housed at Fort Leavenworth," Republican Kansas Senator Sam Brownback said in a statement.
"This is a bad idea chasing after another bad idea on a hurry up timeline."