Nearly a year has passed since President Barack Obama's self-imposed deadline to shutter the camp, but his spokesman said legal and legislative hurdles would prevent reaching that goal any time soon.
"It's certainly not going to close in the next month. I think it's going to be a while before that prison closes," Robert Gibbs told CNN's State of the Union program on Sunday.
Obama views Guantanamo, which conjures up images of water-boarding and other alleged torture, as a prime symbol of Bush-era war on terror excess that only serves as a recruiting tool for Al-Qaeda.
But his efforts to shut down the prison camp on the southern tip of Cuba have struggled as allies baulk at taking in higher-risk inmates and prosecutions become bogged down in a legal quagmire.
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Only three of the remaining 174 detainees have been formally tried and found guilty. Dozens have been cleared but no foreign ally will accept them and there is strong American opposition to any being allowed on US soil.
US lawmakers effectively blocked one avenue this week by approving a Pentagon budget that forbids funding for an alternate prison, relocating prisoners to the United States or sending detainees to certain countries.
Gibbs called for help from Obama's Republican foes, who in January will gain control of the House of Representatives and trim the Democrats' Senate majority after landslide mid-term election gains.
"I think part of this depends on the Republicans' willingness to work with the administration on this," he said.
"Are they willing to listen to others in the national security arena that have told us and will tell them and have, quite frankly, told the public that Al-Qaeda recruits young people to do harm, to try to blow up airplanes, to blow up themselves and kill others, they use that as a recruiting tool?"
Senator Lindsey Graham, a South Carolina Republican, was in talks that eventually broke off with the White House for a negotiated solution.
Gibbs appeared to acknowledge a draft executive order -- previously only mentioned anonymously by officials -- to formalise the indefinite detention of some Guantanamo detainees but allow them to challenge their incarceration.
"Some would be tried in federal courts, as we've seen done in the past. Some would be tried in military commissions, likely spending the rest of their lives in a maximum security prison that nobody, including terrorists, have ever escaped from," he said.
"And some, regrettably, will have to be indefinitely detained."
