"It's extremely inefficient," said Ken Gude, chief of staff and vice president at the liberal Center for American Progress think tank, who has followed developments at Guantanamo Bay since 2005.
"That ... may be what finally gets us to actually close the prison. I mean the costs are astronomical, when you compare them to what it would cost to detain somebody in the United States," Gude said.
The cost argument could be a potent weapon at a time of running budget battles between Obama and the Republican-controlled House of Representatives, and of across-the-board federal spending cuts that kicked in in March. The "sequestration" as it is known, is due to cut some $109 billion in spending up to the end of September and has cut government services small and large.
Just one inmate from Guantanamo, for example, is equivalent to the cost of 12 weeks of White House tours for the public - a treasured tradition that the Secret Service says costs $74,000 a week and that has been axed under sequestration.