Washington (CNN) Congress is again up against the wire on a bill to avoid a government shutdown.

But last-minute brinkmanship, which has become the norm on Capitol Hill, could be in the rear view mirror by Thursday afternoon if House Republicans can find enough Democrats to help them approve a mammoth spending bill.

Internal battles among Republicans on spending bills are nothing new. House Speaker John Boehner routinely needs Democrats to help him pass funding bills. But this time House Speaker Nancy Pelosi doesn't seem in the mood to help.

"If we don't finish this today, we're going to be hear 'til Christmas," Boehner threatened at a Capitol Hill press conference.

Democratic and Republican leaders brokered a deal on a $1.1 trillion spending package to fund the government through September and head off a government shutdown, but many liberal Democrats are bailing on the package.

Eleventh hour additions of two policy provisions on campaign finance and banking rules have enraged those on the left who now say the bill is a special interest boondoggle.

The final gasp of the lame duck session is also a pivotal moment for Pelosi, who has publicly criticized the bill and called for those two items to be removed. Republican leaders have refused to make any changes. The top House Democrat has sent strong signals she's vote against the bill, but Democratic leaders weren't officially urging no votes from their members.

"These provisions are destructive to middle class families and to the practice of our democracy," Pelosi said Wednesday, making it clear the bill was unacceptable.

Securing support from a significant chunk of Democrats is critical for House Speaker John Boehner because many of the conservatives in his party - as many as 60 -- will likely oppose it. They have insisted the spending bill should try to reverse President Barack Obama's recent executive actions on immigration. GOP leaders opted to postpone the immigration fight until next year, leading members on the right say they'll vote no.

It's a gamble for House Democrats if they join unhappy Republicans and take the spending bill down. If it fails to pass GOP leaders, who have no appetite for a government shutdown, will move quickly to pass a three-month extension of current funding levels for federal agencies. Those items that Democratic negotiators fought to get included in this legislation -- and the GOP policy changes to gun laws and environmental policies they opposed and blocked -- will be lost. Democrats would lose any leverage they had on any new deal early next year when both the House and Senate are controlled by Republicans.

"We argued. We debated. We fought," said Sen. Barbara Mikulski, D-Maryland, the chair of the Senate Appropriations Committee and one of the chief negotiators on the spending bill. "You know - sometimes you give a little, you take a little."

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Many House Democrats emphasize they were initially concerned with the spending deal because it only funds the Department of Homeland Security through February. DHS includes immigration and border control agencies. A new funding battle for DHS in February would tee up a fight over President Obama's immigration action early next year.

The other policy provisions added to the spending bill - one increasing the limit rich donors can give to national party committees, and one rolling back a key financial reform barring banks from using taxpayer-insured money for derivatives trades - have made it even more unpalatable.

"At this point I don't see many Democratic votes at all for a bill that is so antithetical to the middle class," Rep. Steve Israel, D-New York, told CNN before heading into a meeting on the measure on Thursday morning.

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Other Democrats are taking a more pragmatic approach, stressing they are weighing the good with the bad.

"This may be a hold your nose vote," Connolly told reporters, suggesting he could ultimately back the measure and any deal next year would only get worse for the programs he cares about. Connolly's district is home to tens of thousands of federal workers who got a small pay raise as part of the deal.

The number two House Democrat, Steny Hoyer, who is in charge of whipping votes, wouldn't say how he would vote.

"We're holding our powder dry," Hoyer said.

House Republican aides feel comfortable that even with large opposition in Democratic ranks they can get enough votes for the measure to eke out its passage.

If it passes, the bill will be sent to the Senate, where many of the same divisions exist.

While the debate over the measure will echo the bitter partisan tone that's been the marker of this Congress, one thing unites virtually everyone on Capitol Hill. They all hate the name of the bill -- dubbed the "Cromnibus" for a combination of a "continuing resolution" and an "omnibus" spending bill.

"It sounds like a horrible disease," said one House Republican. A Democrat called it the "Crummy-bus."