The Senate on Sunday will begin what could be a long parliamentary process to pass both the Bipartisan Budget Act and the National Defense Authorization Act, though votes won’t take place until later in the week.

Senate Majority Leader Harry Reid (D-Nev.) said Friday morning that the Senate will convene Sunday at 1 p.m. for legislative business but not votes, where he will bring up both bills and move to quickly end debate on them. Senators will then try to move toward a vote on the budget bill on Tuesday and the defense bill on Wednesday. They are set to leave Dec. 20 for the remainder of the year.United States Capitol

“The Republican leader and I have spent some time together, and I think we’ve had a productive discussion on the schedule–the schedule’s been extremely difficult for everyone,” Reid said on the floor. “There is a lot of work we have to do to get back to regular order. We’ll see what happens with the defense bill that we’re going to vote on and the budget bill, but I’m satisfied that we’ve made progress.”

The process of passing the two bills might not be so simple, however. This week, as the House worked to pass the two pieces of legislation, the Senate tackled a long list of presidential appointees waiting to be confirmed–but they did so by voting at odd hours of the night, in session essentially nonstop from 2 p.m. Wednesday to 2 p.m. Friday, as some senators used parliamentary procedures to delay votes and take up time on the floor to address non-related issues.

Some Republican senators have said they intend to do the same with the defense bill, vowing to use any and all tactics available to them to force an open debate on the bill and amendments they wish to make to it.

Reid cannot allow amendments on either bill, though, if they are to be passed and signed into law by the end of the calendar year, as the House is out until January.

If the budget bill stalls until the House returns, it would shorten the amount of time the appropriations committees have to draft and pass their line-by-line spending bills to fund the government for the rest of the fiscal year. Funding expires Jan.15, and failure to pass appropriations bills by then would result in another government shutdown.

If the defense bill stalls in the Senate for the second time this year, several authorities–primarily combat pay and other special pays and bonuses–will expire, advance procurement of parts for Virginia-class submarines will continue to be halted, and the aircraft carrier USS Gerald R. Ford (CVN-78) will quickly approach a cost cap that the NDAA raises, according to the Pentagon and lawmakers.