WASHINGTON – White House aides are increasingly convinced that accused 9/11 mastermind Khalid Sheikh Mohammed will never be tried in a civilian court and are trying to cut a deal that would still transfer Guantanamo Bay terrorism suspects to the United States, where many would face charges, a senior administration official said Monday.

President Obama is trying to keep a campaign pledge to close the U.S. military prison in Cuba, a promise that has attracted criticism from Republicans who say it would jeopardize national security. He also has lately been under fire from people within his party who say Obama should not accept any deal that would prosecute Mohammed outside the normal judicial system.

But a senior official said the most important goals are closing Guantanamo Bay and ensuring that the government can prosecute some detainees in U.S. courts. To do so, the only option may be abandoning the administration’s original plan to prosecute the alleged 9/11 conspirators in civilian courts and allow them to go before military tribunals.

Sen. Lindsey Graham is seen as key to the deal. Over the weekend, the South Carolina Republican expressed willingness to cut a deal that leads to closing Guantanamo Bay.

“If we could get Khalid Sheikh Mohammed and the co-conspirators of 9/11 back in the military commission, it’d go down well with the public,” Graham said on CBS’ “Face the Nation” program.

But the deal is far from done. The White House does not want to hold military commissions at Guantanamo Bay. That means the administration would need a deal to close the prison and hold military commissions within the United States.