With just weeks to go before their deadline, Republicans on the House Budget Committee have yet to break their stalemate on spending levels, leaving open the chance of a government shutdown showdown mere months before the November elections.

Speaker John Boehner (Ohio) and GOP leaders have remained silent about the issue and have yet to stem the tide of another conservative revolt from within their ranks. Based on last year’s battles, it’s not clear they can.

Members of the conservative Republican Study Committee are seizing their last chance to take a chunk out of Congressional spending, working behind closed doors to reduce the spending cap agreed to in July’s Budget Control Act.

“I look at the big picture first. I think it is clearly important we draw a contrast with this president,” RSC Chairman Jim Jordan (Ohio) said. “We’re saying, ‘Let’s show the contrast and let’s stick to what Republicans championed last year.’”

Jordan said he sees the tide turning in his direction in the negotiations. But the campaign could materialize into an election-year doomsday scenario for Republicans.

Even if the House budgeteers succeed in lowering their topline number, Senate Appropriations Chairman Daniel Inouye  indicated in an interview that there is little interest among Senate Democrats to follow suit.

“We’ve got this Budget Control Act, and that’s the law of the land,” the Hawaii Democrat said.

House Appropriators, meanwhile, warn that passing a budget lower than the agreed-upon $1.047 trillion in the BCA would imperil their mission to bring bills to President Barack Obama’s desk before Sept. 30, when the current spending bills expire.

Absent new spending bills for fiscal 2013, Congress would have to pass a continuing resolution to keep the government operational past Sept. 30.

Hard-line conservatives, willing to challenge their own leadership on spending levels, would not likely bow to the Senate in those cross-Dome budget negotiations. And in that case, some Congressional observers see a potential government shutdown as a very real possibility.

“I don’t think that’s likely to happen, but that could happen,” said Oklahoma Rep. Tom Cole, a Republican member of the Appropriations and Budget committees. “We’re going to pass a CR anyway, but when we move into negotiations with the Senate, it’s better if we have actually passed a bill first.”

Still, that is months away, and for now, House Budget Chairman Paul Ryan is hoping to pass the budget out of committee by the end of this month.

He and his staff are holding meetings with Members all week. But it remains unclear yet if the Wisconsin Republican — a Member of the RSC himself — has the votes in his committee to pass any budget at all.

Nine Republican members of the committee voted against the final version of the BCA and are resistant to agreeing to that spending level. They hope to influence Ryan to introduce a budget at $930 billion.

Democrats and some Republicans might not agree to vote for such a low number, however.

Rep. Mick Mulvaney (R-S.C.), a member of the RSC and the Budget Committee, said he is trying to broker a deal with skeptical Republican appropriators in which they vote for the lower budget with the promise that the RSC Members will vote for their appropriations bills that conform to that number. That would mean Republicans could pass their bills without Democratic votes.

But the promise rings hollow in the corridors of the Appropriations Committee.

“It is not realistic or sensible to assume that there would be enough promised votes to make up for the 50 to 60 Republicans that consistently oppose any appropriations bills,” a GOP aide said.

Mulvaney also said he could be swayed to approve a higher spending limit if Ryan introduced a plan to balance the budget within 10 or 12 years instead of more than 20.

“There is no concerted effort here to try to shipwreck the budget,” Mulvaney said. “We’re trying to get to a unified Republican budget without the Republican Study Committee offering their own budget.”

House Minority Leader Nancy Pelosi indicated Thursday that her Democratic Caucus would offer little assistance passing Ryan’s budget because of his promised changes to Medicare. She said Budget ranking member Chris Van Hollen (Md.) will introduce a Democratic budget later this year.

“We will have our Democratic House budget as we go forward,” the California Democrat told reporters. “It will not end the Medicare guarantee or have initiatives in it that can cause Medicare to wither on the vine.”

The episode is making for unlikely bedfellows. Senate Minority Leader Mitch McConnell (R-Ky.), House Republican leaders and Democrats all seem to favor the BCA number, while a faction within the Republican Conference wants to go lower.

“I think it’s just a matter of delay because eventually we’re going to have to come back to that number,” said Rep. Jim Moran (D-Va.), an appropriator. “They’re just trying to prove a point.

“They’ve got a tiger by the tail right now. I don’t know how they rein it in,” he added.