Senate Armed Services Committee Chairman John McCainJohn McCainRepublicans tie Trump's Defense pick to funding fight Lawmakers haggle over funding bill as shutdown nears Markos Moulitsas: Kill the filibuster MORE (R-Ariz.) was one of the administration's few Republican allies on closing the Guantánamo Bay prison.
But this week, he says, the administration lost him.
"Whether I happen to want to or not," he added. "I do happen to want to, but the vote has always been overwhelming. So it's too bad," he said at a roundtable breakfast.
The administration had been counting on McCain, a former prisoner of war, to rally support for closing the detention center along with McCain's allies like Sen. Lindsey GrahamLindsey GrahamEx-Im Bank fails to get quorum reprieve in stopgap spending bill Overnight Defense: Funding bill would ease Trump Defense pick's confirmation | Obama delivers final security speech Congress wants hearing on Pentagon wasteful spending charges MORE (R-S.C.), a retired military lawyer.
But McCain expressed disappointment with the plan the administration released this week, seven years after he first asked the president for one.
The plan is, McCain said, a "Chinese menu."
"Seven years later, he still doesn't have a plan ... it's a Chinese menu. One from column A, one from column B, and 13 different sites," he said.
The administration submitted the plan to Congress as required by a provision McCain wrote last year into the defense funding measure. The proposal is likely the president's last chance to work with Congress before his term ends.
If Congress were to approve the plan, a prohibition against bringing detainees to the U.S. would be dropped.
But the proposal was supposed to name a specific facility or facilities where detainees could be held, and to specify the associated costs. The Pentagon began surveying possible sites last year in Colorado, Kansas and South Carolina.
The administration referenced 13 possible sites in its eight-page plan but did not endorse any single one. The proposal also includes a seven-page memo from May 14, 2014, that outlines what rights the detainees would have and not have.
But McCain said it left many questions unanswered.
"We have to know how these people are going to be treated. We are going to be capturing terrorists in the future. What's the plan for that? How are they going to be interrogated?" he asked.
"What laws of war are we going to be operating under? In this facility, if we find it, then what will be make up of that? There are so many questions that need to be answered, it seems to me they just decided to throw up something and see if anything can come of it," he said.
Still, McCain said, he anticipates having a hearing on the plan early next month.
"We're have a hearing on it. We'll have a hearing — I think the week after next is what we are looking at. I think it deserves a hearing," he said. "But on both sides — both Republicans and Democrats, I can assure you — from my conversations, this has been met with great skepticism."
McCain said it was just about four months ago that he offered the president his assistance on the plan.
"I said, 'Well, I'd like for you to sort of, maybe we could be part of this process, and maybe make some input into it, especially Lindsey Graham,' " he said.
But that never happened, McCain said.
"Sen. Lindsey Graham has the unique qualifications of having been a military lawyer for 33 years. They've never even given him a call," he said.
He said any other administration would have called on the chairmen and ranking members of the Senate and House Armed Services committees in for a briefing ahead of time.
"So this is the problem that you get when you don't communicate with people," he said. "And so they air drop it in. So every other administration — Republican or Democrat — would have called me, [Rep. Mac] Thornberry [R-Texas], Lindsey Graham, [Rep. Adam] Smith [D-Wash.], over and said, 'Ok, here's our plan.'
'What do you think about this,' etc., and we could have had an exchange. Or before the plan, they would have said, 'We want your input.' There's none of that with this administration. So they shouldn't have been surprised at the reaction to it."
McCain said the president did, however, call him on Monday night to let him know a plan would be coming over.
"I thanked him. I said I wish that we had more consultation and discussion about it but ... what was done is done," he said.
With the plan hitting Capitol Hill with a thud, McCain said he is "very worried" about the president taking executive action.
"We're already hearing rumors that the president's legal advisers are telling him Congress is violating executive powers," he said.
"It would be a serious mistake, in my view, for him to do it. But he's done it in other areas whether it'd be immigration, whether it be the EPA, both of which by the way have been stayed by the courts," he said.
"We've upset the constitutional balance here. ... People who otherwise would be agreeable to listening to the administration want to protect the constitutional role of the Congress," he said.