Updated

Senate and House Democrats are working feverishly behind the scenes to pull together a supplemental war funding bill while trying to resolve a major sticking point -- the denial of funds to close the Guantanamo Bay prison facility until the Obama administration presents a detailed plan for closing it.

Senate Majority Leader Harry Reid, D-Nev., aware that the Senate recently voted overwhelmingly, 90-6, to ban the use of all federal funds to close the facility and bring Guantanamo prisoners to the United States. for incarceration without a detailed plan, is inviting the White House to make its case to his party.

It's not clear whether that will help.

Reid invited Deputy National Security Advisor Tom Donilon to meet with Senate Democrats in a special caucus Wednesday night so that he could make the politically unpopular case for transferring some detainees ashore, according to one senior Senate Democratic leadership aide.

"We need 60 votes, ultimately, so there still needs to be more discussion," the aide told FOX News, saying the White House intends to ratchet up the pressure to get the troop funding bill through Congress.

Another Senate Democratic leadership aide was more blunt. "There was a lot of skepticism in that room. This is not popular. I don't know how they're going to get this through," the aide said, referring to any softening of Senate language.

Republicans are worried that Senate Democrats will cave and accept House-passed language that merely bans the use of supplemental funds to begin to close Guantanamo.

"Money can be reprogrammed by departments to close the facility if we don't stop that, and that's what the Senate did," said one senior Senate Republican leadership aide.

"Now, they want to water that down," the aide added, "and we're going to fight that tooth and nail."

The other thing the administration appears to be asking is for a legal escape hatch to bring Guantanamo prisoners to the United States for trial. Another senior GOP leadership aide told FOX News that the concern is that once prisoners are brought to the U.S. for trial, if they are here for the ruling and are found not guilty by the presiding judge, the detainee can be released into the United States.

House Democrats want to try to move by the end of this week or early next the nearly $100 billion supplemental for troop funding in Iraq and Afghanistan. The Senate would then follow that action.