A December full of deadlines is finally here.

In the remaining weeks of 2021, before members of Congress can head home for the holidays and ring in the new year, they have to take care of a few crucial matters:

• First, the Senate has to take up and pass the military spending bill for the 2022 fiscal year, which passed the House in September
• After that, Congress must pass a bill to fund the government beyond Dec. 3.
• Then, Congress has to come to an agreement on the debt ceiling by Dec. 15 to avert the nation defaulting on its debts.
• And all the while, Senate Democrats are planning to take up President Joe Biden’s $1.85 trillion social spending and climate change bill, the Build Back Better act.

All this while the 2022 midterms, and control of Congress, loom just over the horizon.

No small feat for any Congress, much less one as evenly divided and fractious as this one.

But Congressional leaders are confident that they can make everything work.

"We know that December is upon us, we know we have a lot of work to do," Senate Majority Leader Chuck Schumer, D-N.Y., said. "We’ll get the job done."

The military spending bill — the National Defense Authorization Act (NDAA) — passed the House of Representatives in September with a widely bipartisan 316-113 vote. 

Congress has passed the NDAA for six consecutive decades under both Republican and Democratic control, including in 2021, when then-President Donald Trump vetoed the bill. The Republican president rejected the bill because it did not repeal a 1996 internet communications law which protects speech online, but the House and Senate both overrode Trump’s veto — a first for his presidency — in bipartisan fashion.

The Senate voted last week to advance the defense bill in bipartisan fashion, 84-15, after negotiations on the inclusion of Senate Majority Leader Chuck Schumer’s anti-China competitiveness legislation held up the vote.

Schumer dropped the provision after he and House Speaker Nancy Pelosi, D-Calif., struck a deal to reconcile the competitiveness bill, and the Senate voted to move on to debating the $780 billion defense spending bill. 

But lawmakers are still haggling over a mountain of amendments to the bill, which could continue to slow proceedings down. Lawmakers are working to negotiate on a deal which would make the amendments more concise, leading to quick passage.

POLITICO reported this week that U.S. allies expressed concerns to lawmakers at a security forum in Canada over the weekend that the bill has yet to pass, and might not be enacted before the end of the year. Democrats and Republicans were frustrated by the delays.

“Don’t mess up the one thing that you can count on the Senate to do in a bipartisan way every year,” Sen. Tim Kaine, D-Va., said, per the outlet. “A Senate that cannot do this hardly deserves the title.”

Mississippi Sen. Roger Wicker, a Republican, noted the bill has passed far earlier in recent years: “There were a lot of us … who asked the majority leader to bring it up earlier so we have time.”

Congress must also quickly take action to address the debt limit and fund the government.

In October, Congress passed a short-term measure to fund the government through Dec. 3 and increase the debt limit by $480 billion, staving off both a shutdown and the United States defaulting on its debts for the first time in its history.

But kicking the can down the road, so to speak, only bought lawmakers two months before having to deal with both issues again.

Treasury Secretary Janet Yellen warned last week that the federal government will not be able to honor its financial obligations after Dec. 15 unless Congress votes to raise or suspend the debt limit.

“To ensure the full faith and credit of the United States, it is critical that Congress raise or suspend the debt limit as soon as possible,” Yellen wrote in a letter to Speaker Pelosi.

Yellen has previously warned that if the the federal government cannot pay its bills, defaulting for the first time ever, it likely would trigger a “historic financial crisis,” which would include interest rates spiking, stock prices plunging, the country entering a recession and millions of jobs being lost. 

It could also mean seniors not collecting Social Security checks, troops going unpaid and families not receiving child tax credit payments. 

In her letter, Yellen explained that the new infrastructure law signed Monday by President Joe Biden allocates $118 billion that must be transferred into the Highway Trust Fund by Dec. 15. Those funds are then invested in nonmarketable treasury securities that are subject to the debt limit. 

“While I have a high degree of confidence that Treasury will be able to finance the U.S. government through December 15 and complete the Highway Trust Fund investment, there are scenarios in which Treasury would be left with insufficient remaining resources to continue to finance the operations of the U.S. government beyond this date,” Yellen wrote.

As they did in October, Republicans have once again urged Democrats to go it alone on raising the debt limit, telling them to include an increase in President Biden’s social spending and climate change Build Back Better bill.

However, Congress has routinely raised or suspended the debt limit regardless of which party’s president is in the White House. Democrats have noted they voted three times with Republicans to do so under former President Donald Trump.

After months of debate and deliberation, the House of Representatives last week passed President Biden's nearly $2 trillion social spending and climate change bill, the Build Back Better act. And on the first day back from the Thanksgiving recess, Senate Majority Leader Chuck Schumer, D-N.Y., reiterated that his goal is to pass the bill before 2022.

"Our goal continues to be to get this done before Christmas," Schumer said Monday. 

Along with the $1 trillion infrastructure bill, the sweeping measure is includes funding for universal pre-Kindergarten, reducing prescription drug costs and the largest-ever legislative investment to fight climate change. It will be funded largely by a combination of tax increases on the wealthiest Americans, large corporations and companies doing business overseas.

Even after all the haggling and back-and-forth between lawmakers, the House's initial passage of the bill may end up being the easiest part.

The bill is now in the hands of the Senate, where it faces a long road – including the need to win over moderate Sens. Kyrsten Sinema, D-Ariz., and Joe Manchin, D-W.Va., and survive the Senate's budget reconciliation process, which means more changes to the massive measure could be coming.

First, the bill needs to go through what's known as a "Byrd Bath" process – named for the late West Virginia Sen. Robert Byrd – under which provisions of the bill will be scrutinized under the chamber's arcane budget rules to see if they can stay in the bill.

Some provisions of the bill, likely popular ones, will no doubt be stripped out if they don't fit those rules. Those could include immigration provisions, which the Senate's parliamentarian – the chamber's nonpartisan arbiter of the rules – has previously rejected.

Schumer said Monday that meetings with the parliamentarian are ongoing, but once they're done, he will bring the bill up for a vote: "Once this necessary work is completed with the parliamentarian, I will bring the president's Build Back Better legislation to the floor."

Then the bill will go through the "vote-a-rama" process, under which lawmakers can propose dozens and dozens of amendments, many of which will likely fail, but could delay the process and force difficult votes.

After all that, then the final version of the Senate bill must be reconciled with the House, which could prove difficult with such a tenuous, delicate agreement between Democrats, with their razor-thin majority in Congress.

But the White House's chief economic adviser and the Senate's majority leader both expressed optimism last Sunday that Biden's Build Back Better bill will clear the Senate and make it to his desk to be signed.

Appearing on “Fox News Sunday” last week, White House National Economic Council director Brian Deese said that the Biden administration will work with “every member of the Senate” as Democrats attempt to find compromise and advance the president's bill through the evenly divided chamber.

Deese said that, despite concerns from moderate Democrats, the Build Back Better act contains provisions that are popular with the entire party — such as lowering the cost of child and elder care.

“We have broad agreement on those provisions," Deese said Sunday. "And so I expect as we move to the Senate, we will have a lot of momentum."

Speaking at a news briefing last week, Majority Leader Schumer stressed party unity, signaling he was open to negotiating with Manchin and Sinema to address their concerns.

"The House did a very strong bill,” he said. “Everyone knows that Manchin and Sinema have their concerns, but we're going to try to negotiate with them and get a very strong, bold bill out of the Senate which will then go back to the House and pass.”

Asked Sunday he thinks the package could pass the Senate, Schumer said: "I think we're in very good shape to get 50 votes," but that he knows Republicans in the chamber will look for ways "to try to knock it out."

Despite challenging odds, the White House is optimistic the bill will pass.

In working closely with lawmakers this fall as they worked to advance both the infrastructure bill and the larger domestic spending package, the White House now has “a good understanding” of where consensus lies in the evenly divided chamber, Deese said Sunday.

"We will work with every member of the Senate on this bill,” Deese said. “But I think that because of that work over several months, we really do now have a good understanding of where the consensus lies.”

Appearing Sunday on NBC’s “Meet the Press,” Sen. Jon Tester, D-Mont., echoed the cautious optimism shared by Deese and others.

Tester acknowledged that while the bill is likely to undergo some changes before it is brought for a floor vote, “reasonable people” in the chamber “can come up with a bill that is a very, very good bill, [one] that works for states like Montana and other states in the area.”

“We don't all see the world the same way, so let's negotiate, and let's come up with a bill that lowers costs for families and cuts taxes … and gets things done to help move this economy forward, so we can stay the premier power in the world,” Tester added.

Spectrum News' Ryan Chatelain, Breanne Deppisch, Rachel Tillman and Austin Landis contributed to this report.