With House and Senate lawmakers intent on finishing up the appropriations process before Sept. 30, President Barack Obama faces a tough timeline this summer for getting the money he wants to close the Guantánamo Bay, Cuba, military prison.

Democrats on both sides of the Capitol say that at the very least they want to pass all 12 appropriations measures — including the Defense Department spending bill that would contain any Guantánamo closure money — by the end of the fiscal year.

However, Obama has been waiting for a report from a special interdepartmental task force on how to deal with the hundreds of suspected terrorists now housed at the facility. That report is not due until July 21 and could come too late for House Appropriations Chairman David Obey (D-Wis.), who has set a goal of having all his spending bills passed by the House before it recesses on July 31.

“There’s a train leaving town, which is Defense appropriations, and if [Obama] wants the funding on that train, he needs to one, come up with a plan, and two, convince a majority of Congress to support that plan,— said one senior Senate Democratic aide.

Senate Appropriations Chairman Daniel Inouye (D-Hawaii) has set a goal for the end of the fiscal year for floor passage of the appropriations bills. The Senate traditionally waits for the House to act on spending bills first, which might give Obama time to get the money into the Senate version of the DOD bill.

Plus, Inouye has left the door open to that, saying on the floor last month that: “Many of my colleagues are justifiably concerned about how the terrorists at Guantánamo will be handled. They deserve answers, but so, too, we must begin planning to close the prison.

“That work needs to begin soon for the good of our nation and the men and women still serving in harm’s way. It is up to the administration to fashion a plan, which can win the support of the American people and its Congressional representatives. As we approach the fiscal year 2010 budget, this will be a key element of our continued review of this matter.—

And it’s not as if the interdepartmental task force’s report will be delivered in a vacuum. One Justice Department official said Members of Congress and the White House are regularly consulted on the group’s progress and that the report is likely to contain input from both ends of Pennsylvania Avenue.

Though Obama used one of his first executive orders to direct his new administration to close Guantánamo by January 2010, he experienced a backlash from Congress for not having a specific plan for where to send the detainees nor for how to deal with them in either U.S. civil courts or military commissions.

Both the House and Senate bucked Obama’s budget request to include roughly $80 million for the facility’s closure in the supplemental war spending bill that passed both chambers last month. But Democrats in both chambers went even further in that bill and prohibited Obama from ever transferring detainees to the United States or from ever releasing them on U.S. soil.

They also refused to give him any money to close the prison until he outlines his plan for detainees. That Congressional imperative will likely become law in the next two weeks, when the House and Senate finalize the supplemental conference report.

Still, Obama has general support from Democratic leaders in both chambers for closing Guantánamo, and aides said that whatever he comes up with will likely have the votes — assuming he uses the bully pulpit of the White House to drive the public relations message.

“At the end of the day, the president is going to present the Congress with a plan that he feels is strong enough to answer the concerns of many Members of Congress, and we’ll have the votes to pass it,— said one senior House Democratic aide.

But Obama will have to work hard to sell the plan if it involves bringing detainees into U.S. maximum security prisons, as appears likely. Republicans have hammered Democrats with warnings that such a move would endanger national security. That has made some vulnerable Democrats more nervous about supporting Obama.

“In order to get Members to walk the line for him on this, he’s going to have to put meat on the bones. He’s going to have to put a lot of meat on the bones,— the senior Senate Democratic aide said.

The House aide agreed but said the president will likely get his way: “At the end of the day, it’ll get done.—