Lawmakers are struggling to raise the national debt limit by Dec. 15 and avoid a catastrophic default for the first time in U.S. history.

Republicans are insisting Democrats should raise the debt limit using budget reconciliation but Senate Majority Leader Chuck Schumer, D-N.Y., is reluctant to do so because the process would require at least a week of Senate floor time. The process would also include two long series of votes on amendments, called a vote-a-rama. The first vote would amend the 2022 budget resolution and the second vote would raise the debt limit.

Senate Minority Leader Mitch McConnell, R-Ky., will not be able to round up 10 Republican senators to agree to raise the debt limit thus making the negotiations much more complicated. Without bipartisan support, any effort to raise the debt ceiling will be met with a Republican-backed filibuster.

The negotiations come as Democrats struggle to pass the $1.75 trillion social spending bill, the most vital part of President Joe Biden’s economic agenda.

Despite the impasse, Schumer expressed confidence that both agenda items will be completed by the end of the year, and doing so “will take some long nights and weekends,” Schumer said.

Congress agreed to temporarily suspend the debt ceiling in October and time is running out yet again. If the U.S. were to default on its debt it would have disastrous economic consequences and would plunge the nation’s economy into a recession.

According to The Hill, a Senate Republican aide predicted Treasury Secretary Janet Yellen would be able to come up with additional “extraordinary measures” to keep the government funded past the mid-December deadline and give Schumer and McConnell more time to reach an agreement.

“My expectation is that Yellen is going to find a couple of extra quarters in the cushions and push it to January or February,” said the aide.