(CNN)The Senate on Tuesday passed and will send to the White House a broad defense policy bill that would block the President from bringing terrorism suspects held in Guantanamo Bay, Cuba, to the United States.
Senate passes defense bill blocking Obama's Guantanamo plan
Unknown is whether President Barack Obama -- who made closing the detention center a key campaign promise -- will veto the bill or sign it despite the Gitmo restrictions.
The overwhelming and bipartisan vote was 91 to 3, which means it has more than enough supporters to override a presidential veto, though Obama's Press Secretary Josh Earnest said the President would sign the defense bill.
"A number of provisions in the NDAA that are important to running and protecting the country," Earnest said during a White House briefing, adding "that certainly does not reflect a change in our position, or intensity of position, of the need to close the Guantanamo Bay prison."
Congressional Republicans are bracing this week for what they fear will be a decision by the President to cite his executive authority and order the prison closed.
"I think that's likely from everything he's said," said Sen. Richard Burr, R-North Carolina, who chairs the intelligence committee.
But it was not clear if the President planned to issue such an order or simply release a plan to Congress with recommendations for how to close the controversial base. The recommendations, which come from the Department of Defense, are expected to list pros and cons of possible places to house detainees within the U.S., including locations in Kansas, South Carolina and Colorado.
On Monday, Obama's spokesman didn't rule out executive action.
"I certainly wouldn't take off the table the ability of the President to use whatever authority is available to him to try to move closer to accomplishing this goal," said White House Press Secretary Josh Ernest. "I don't say that with any specific action in mind. I just say it to illustrate to you the determination that the President feels to try to get this done."
Meanwhile, one of the few GOP proponents of shutting the prison is frustrated the White House hasn't developed a comprehensive plan to do so.
"We need a specific plan, one that I've been seeking for six and a half years," said Sen. John McCain of Arizona, the chairman of the Armed Services Committee, who predicted that whatever the President releases "won't be satisfactory."
McCain also said if Obama acted unilaterally, it would "undermine the Constitution of the United States." He predicted congressional Republicans would turn to the courts to block the action.
Senate Majority Leader Mitch McConnell warned the President not to act on his own, noting that Congress has repeatedly voted to ban Gitmo prisoners from coming to the U.S.
"Each of these bills contains a clear, bipartisan prohibition on the President moving Guantanamo terrorists into the backyards of the American people," McConnell said before the vote.
If the President did act unilaterally, it would infuriate GOP lawmakers, especially those from states where the detainees could be sent.
In a conference call set up by the Republican National Committee, senators from South Carolina, Colorado and Kansas, blasted the idea of prisoners being forced on them.
"Why in the world you would bring these enemy combatants to domestic soil is mindboggling. This is nothing short of gambling national security to keep a campaign promise," said Sen. Tim Scott, R-South Carolina.
Sen. Pat Roberts of Kansas, which is home to a major Army prison at Fort Leavenworth, suggested any prison that held terrorism suspects would be subject to attack by other terrorists.
"What does that mean with regard to the security and the danger of that community?" Roberts asked.
McCain said he had worked with the administration to develop a plan to close the base that he might be able to sell to skeptical GOP senators. But he said beyond an initial meeting with Secretary of Defense Ashton Carter and Lisa Monaco, a top national security official in the White House, the effort never went anywhere.