Democrats and Republicans alike aim to tuck as many legislative wish-list items as possible into the "omnibus" bill funding the government through the end of its fiscal year on Sept. 30, 2023, without derailing the whole package.
Failure could bring a partial government shutdown beginning Saturday, two days before Christmas, and possibly lead into a months-long standoff after Republicans take control of the House of Representatives on Jan. 3, breaking President Joe Biden's Democrats' grip on both chambers of Congress.
"Nobody is going to get everything they want, but the final product will include wins everyone can get behind," top Senate Democrat Chuck Schumer said late Thursday after lawmakers passed a week-long funding bill intended to allow them to finish work on the sprawling omnibus bill.
The full details of that package were being crafted over the weekend, but it will include a record $858 billion for defense -- some $45 billion more than Biden proposed -- additional aid for Ukraine, and funding for agencies ranging from the Department of Homeland Security to the Department of Agriculture and the Environmental Protection Agency.
Democrats wanted comparable increases in defense and non-defense spending, which Republicans objected to, saying that Biden's party had passed several other domestic spending bills during the last two years when they had full control of Congress.
"Republicans simply were not going to lavish extra-liberal spending" on non-defense programs into the omnibus bill, Senate Republican Leader Mitch McConnell said last week.
The Senate's cumbersome rules mean that it could take a few days for the funding bill even to come to a vote, after which the House will need to pass it. The bill will need at least 10 Republican votes to pass the Senate, but can pass the House with just Democratic support before going to Biden for his signature.
Democratic House Speaker Nancy Pelosi on Friday said she supported using the bill to pass a measure, approved by the Senate last week, to bar federal employees from using the Chinese-owned TikTok video app on government-owned devices.
Pelosi's support, along with that of Representative Kevin McCarthy, the top House Republican, who aims to succeed her as speaker, significantly boosts the chances the provision will be adopted.
Another add-on to the spending bill appeared certain: Republican and Democratic leaders have agreed to clarify and tighten the way U.S. presidential election winners are certified by Congress. The move is in response to the Jan. 6, 2021, riot at the Capitol by Republican then-President Donald Trump's supporters, who tried to force then-Vice President Mike Pence into ignoring Joe Biden's clear-cut victory -- a power Pence did not have -- and ultimately keeping Trump in the White House.
Lawmakers and their aides spent the weekend gauging how to wedge other special initiatives into this catch-all spending bill. Their alternative is to simply abandon certain efforts for now.
That is exactly what has happened with Democrats' drive to provide citizenship to "Dreamer" immigrants who illegally entered the United States as children.
A bipartisan proposal to protect these youth from deportation while also spending more to keep migrants south of the U.S. border sputtered out last Thursday.
Republicans have been blocking such legislation for decades, arguing that U.S. borders must first be "secured."
A deal tentatively has been reached on a criminal justice matter. A provision could be added to the omnibus to address prison sentencing disparities between illegal use of crack cocaine and powder cocaine.
A decades-old law resulted in far more harsh sentences for Black people using crack, according to civil rights and human rights organizations.
Meanwhile, there were no discernable signs that Democrats were gaining traction on including a renewal of an expired expanded child tax credit. Republicans have balked, largely citing the cost to the government, while pushing for the renewal of some business tax breaks.
Democratic Senator Sherrod Brown signaled his support for a tax code that bolsters U.S. manufacturing. But he wants it coupled with the enhanced child tax credit.
"What are we here to do in this body, if not to make things just a little bit easier" for struggling families, he said.
The risk with each add-on is that it could cost critical votes needed for passage through the narrowly divided Congress.
McConnell has warned that if an omnibus is not headed toward enactment by Thursday, he would support "pivoting" to a third short-term funding bill that he would want to extend into the new year.
That is an outcome Biden and his fellow Democrats in Congress will work to avoid.