That puts them all in an awkward position. At a press conference this morning, Sens. John Cornyn (R-TX) and John Thune (R-SD) were at pains to explain away why they requested earmarks that appear in the bill they're now railing against. But it also sets the two parties up for a standoff -- and one side must blink by this weekend, or the lights will start going out in the federal government.
Democrats will try to use the impending deadline to pass the omnibus. If it fails, they can take up a piece of legislation passed by the House known as a "continuing resolution," which will keep the government funded at current levels through next year.
Republican leaders reject both plans. They're demanding that Congress pass a short-term funding measure, which would expire early next year and give the incoming Republicans the power to cut spending significantly.
"The government runs out of money this Saturday," Senate Minority Leader Mitch McConnell warned this morning on the Senate floor. "Congress should pass a short-term CR immediately."
And they're taking dramatic steps to stop Democrats (and their omnibus) in their tracks.
Sen. Jim DeMint (R-SC), who led the GOP's anti-earmark crusade, will use the rules of Senate procedure to force the 2000-page omnibus to be read aloud on the Senate floor -- a tactic which could eat up enough time to force the Democrats' hand.
Some Republican appropriators and others are expected to support the legislation. But vulnerable, and anti-earmark, Democrats are expected to defect, and it's unclear whether the legislation -- which was once expected to pass handily -- can muster the 60 votes it will need to overcome a filibuster.
"There are 23 Democrats who are up in 2012, who I think are -- and I know Senator McCaskill is one of them -- whose said she's going to vote against it," Cornyn told me. "Part of the reason we're doing this is to raise the attention of the American people and let them know what's happening so they can express their outrage."