WASHINGTON — The House rushed headlong Tuesday into a vote on legislation to fund the government, suspend the federal debt limit and provide disaster and refugee aid, forcing a showdown with Republicans who oppose the package despite the risk of a fiscal crisis.

The federal government faces a shutdown if funding stops at the Sept. 30 end of the fiscal year, midnight next Thursday. At the same time, the U.S. risks defaulting on its accumulated debt load if its borrowing limits are not waived or adjusted.

Speaker of the House Nancy Pelosi, D-Calif., shown this month, implored colleagues in a letter late Monday to move swiftly toward reconciling their differences. J. Scott Applewhite/Associated Press

The package unveiled Tuesday would provide stopgap money to keep the government funded to Dec. 3 and extend borrowing authority through the end of 2022. It includes $28.6 billion in disaster relief for the aftermath of Hurricane Ida and other extreme weather events, and $6.3 billion to support Afghanistan evacuees in the fallout from the end of the 20-year war.

“It is critical that Congress swiftly pass this legislation,” said Rep. Rosa DeLauro, D-Conn., chairwoman of the Appropriations Committee, in a statement. The vote was expected Tuesday afternoon.

Backed by the White House, Democratic congressional leaders pushed ahead at a time of great uncertainty in Congress. With lawmakers already chiseling away at the $3.5 trillion price tag of President Biden’s broad “build back better” agenda, immediate attention focused on deadlines to avert deeper problems if votes to shore up government funding fail.

Senate Republican leader Mitch McConnell said he was not about to help pay off past debts when Biden was about to pile on more with a “reckless” tax and spending package.

“Since Democrats decided to go it alone, they will not get Senate Republicans’ help with raising the debt limit. I’ve explained this clearly and consistently for over two months,” McConnell said Monday.

Even if Tuesday’s vote is approved by the House, which Democrats control, it is expected to languish in the 50-50 Senate where Democrats will be hard-pressed to find 10 Republicans to reach the 60-vote threshold needed to overcome a filibuster.

The Treasury Department warned that it will soon run out of cash on hand, and have to rely on incoming receipts to pay its obligations, now at $28.4 trillion. That could force the Treasury to delay or miss payments, a devastating situation.

“Doing so would likely precipitate a historic financial crisis,” wrote Treasury Secretary Janet Yellen in The Wall Street Journal.

Once a routine matter, raising the debt ceiling has become a political weapon of choice for Republicans in Washington ever since the 2011 arrival of tea party lawmakers who refused to allow the increase. At the time, they argued against more spending and the standoff triggered a fiscal crisis.

Echoing that strategy, McConnell is refusing to provide Republican votes, even though he also relied on Democratic votes help raise the debt ceiling when his party had the majority.

Still, some Republican senators might have a tough time voting no.

Republican John Kennedy of Louisiana, whose state was battered by the hurricane and who is up for election next year, said he will likely vote for the increase if “the disaster relief portion is acceptable.” He added, “Because my people desperately need the help.”

Meanwhile, behind the scenes, Democrats are negotiating among themselves over Biden’s big “Build Back Better” package as the price tag likely slips to win over skeptical centrist lawmakers who view it as too much.

House Speaker Nancy Pelosi implored colleagues in a letter late Monday to move swiftly toward reconciling differences, ahead of deadlines to vote on the package. “This week, we must take decisive action on proceeding,” Pelosi said.

Biden’s big initiative touches almost all aspects of Americans’ lives. It would impose tax hikes on corporations and wealthy Americans earning beyond $400,000 a year and plow that money back into federal programs for young and old. It would increase and expand government health, education and family support programs for households, children and seniors, and boost environmental infrastructure programs to fight climate change.

Biden’s plan aims to not just rebuild the country after the COVID-19 crisis and economic fallout, but begin to change longstanding federal spending patterns in ways that provide more services to more Americans, and attempt to level growing income inequality.

With Republicans opposed to Biden’s vision, Democrats have no votes to spare in the Senate, and just a few votes’ margin in the House.

Pelosi has promised a Sept. 27 vote on a companion bill, a $1 trillion bipartisan infrastructure bill of public works projects that enjoys widespread support from both parties in the Senate, though House Republicans mostly oppose it.

Even though that bipartisan bill should be an easy legislative lift, it too faces a political obstacle course. Dozens of lawmakers in the Congressional Progressive Caucus are expected to vote against it if it comes ahead of the broader Biden package. And centrists won’t vote for the broader package unless they are assured the bipartisan bill will also be included.