With their self-imposed 3 p.m. deadline to finish work on a short-term spending measure in the rearview mirror, House Republicans were struggling to wrap up work on the continuing resolution late Thursday afternoon.

Since Tuesday, Democrats and Republicans have been slogging through hundreds of amendments to the CR, which is designed to reduce President Barack Obama’s 2011 budget request by $100 billion. The bill would fund the government from March 4 through the end of the fiscal year.

Majority Leader Eric Cantor (R-Va.) and other leaders have structured the debate to limit amendments. For instance, Democrats have seen many of their amendments shot down because they would increase spending or shift funds between accounts, which are out of order under the rule governing the bill.

Despite these restrictions, Democrats have had a handful of successes. For instance, they were able to cobble together enough votes with moderate Republicans to reinstate hundreds of millions of dollars in funding for police and firefighter programs. Liberals also worked with conservatives and a number of freshmen Wednesday to defeat the F-35 Joint Strike Fighter engine project, which had the backing of leadership but has long been criticized by fiscal hawks.

In the weeks leading up to the CR debate, Cantor, Rules Chairman David Dreier (Calif.) and the rest of the GOP leadership team sought to work with freshmen and rank-and-file Republicans to try to limit the number of duplicate amendments or out-of-order proposals that would slow work on the bill.

But despite their efforts, floor work has dragged on significantly longer than Cantor had expected, and hundreds of amendments remained on the schedule late Thursday afternoon.

As a result, the House was expected to again remain in session well into the night Thursday, and votes are all but assured for Friday and potentially Saturday in order to wrap up the bill before the House leaves for the Presidents Day recess.

Meanwhile, House appropriators have had preliminary discussions about a stopgap spending bill to buy the House and Senate more time to hammer out a final deal. Although an extension is likely because the Senate has not even begun working on its version of the CR, no substantive discussions about the length or cost of the short-term extension have occurred, aides said.

Speaker John Boehner (R-Ohio) has been adamant that the House will not pass a stopgap bill that does not reduce spending below current levels.