There are 245 detainees in the prison. The question of what to do with them is a delicate one that balances the desire to close a facility widely seen as damaging to international U.S. standing with the risks of releasing prisoners who many believe still pose a serious threat.
The Pentagon has said that 61 former detainees have taken up arms against the United States or its allies after being released from Guantanamo. Citing that concern, Secretary of Defense Robert M. Gates said the fundamental challenge "is figuring out how do we close Guantanamo and at the same time safeguard the security of the American people."
Some Republicans accused the White House of acting rashly and without sufficient concern for the potential risks.
"This is an executive order that places hope ahead of reality - it sets an objective without a plan to get there," Rep. Peter Hoekstra of Michigan, the top Republican on the House Intelligence Committee, said in a statement.
The Guantanamo executive order establishes a review procedure to allow officials to examine the cases of all detainees at the prison. The order says the government will determine which detainees can be transferred to other countries and which should be tried in federal courts or in military court martial proceedings.
The order acknowledges that there may be detainees considered too dangerous to be released but who also can't be prosecuted in federal or military courts. The order is vague about how the administration will handle those cases.
The Obama administration could continue to hold detainees accused of being enemy combatants, under the provisions of the Geneva conventions. Otherwise they would have to either transfer the prisoners to other countries or seek a new law allowing some sort of detention without trial - a step the administration has shown little willingness to take.
A second order issued by Obama banned the use of so-called "enhanced" interrogation techniques. For the first time, CIA interrogators would be required to abide by a U.S. Army field manual that limits interrogators to 19 approved techniques and eschews any sort of harsh questioning practices.
The approved techniques all rely on various psychological approaches and prohibit interrogators from making any physical contact with suspects, or using force.
