With a government shutdown five days away, Congress is moving into crisis mode as Speaker Kevin McCarthy faces an insurgency from hard-right Republicans eager to slash spending even if it means curtailing federal services for millions of Americans.

There's no clear path ahead as lawmakers return with tensions high and options limited. The House is expected to vote Tuesday evening on a package of bills to fund parts of the government, but it's not at all clear that McCarthy has the support needed to move ahead.

Meanwhile, the Senate, trying to stave off a federal closure, is preparing its own bipartisan plan for a stopgap measure to buy some time and keep offices funded past Saturday's deadline as work in Congress continues. But plans to tack on additional Ukraine aid have run into trouble as a number of Republicans in both the House and Senate oppose spending more money on the war effort.

Against the mounting chaos, President Joe Biden warned the Republican conservatives off their hardline tactics, saying funding the federal government is “one of the most basic fundamental responsibilities of Congress."

Biden implored the House Republicans not to renege on the debt deal he struck earlier this year with McCarthy, which set the federal government funding levels and was signed into law after approval by both the House and Senate.

“We made a deal, we shook hands, and said this is what we’re going to do. Now, they’re reneging on the deal,” Biden said late Monday.

“If Republicans in the House don’t start doing their jobs, we should stop electing them.”

A government shutdown would disrupt the U.S. economy and the lives of millions of Americans who work for the government or rely on federal services - from air traffic controllers who would be asked to work without pay to some 7 million people in the Women, Infants and Children program, including half the babies born in the U.S., who could lose access to nutritional benefits, according to the White House.

It comes against the backdrop of the 2024 elections as Donald Trump, the leading Republican to challenge Biden, is egging on the Republicans in Congress to “shut it down” and undo the deal McCarthy made with Biden.

Republicans are also being encouraged by former Trump officials, including those who are preparing to slash government and the federal workforce if the former president retakes the White House in the 2024 election. With five days to go before Saturday's deadline, the turmoil is unfolding as House Republicans hold their first Biden impeachment inquiry hearing this week probing the business dealings of his son, Hunter Biden.

“Unless you get everything, shut it down!” Trump wrote in all capital letters on social media. “It’s time Republicans learned how to fight!”

McCarthy arrived at the Capitol early Monday after a tumultuous week in which a handful of hard-right Republicans torpedoed his latest plans to advance a usually popular defense funding bill. They brought the chamber to a standstill and leaders sent lawmakers home for the weekend with no endgame in sight.

After the House Rules Committee met Saturday to prepare for this week's voting, McCarthy was hopeful the latest plan on a package of four bills, to fund Defense, Homeland Security, Agriculture, and State and Foreign Operations, would kickstart the process.

“Let’s get this going,” McCarthy said. "Let’s make sure the government stays open while we finish our job passing all the individual bills.”

But at least one top Trump ally, Rep. Marjorie Taylor Greene, R-Ga., who is also close to McCarthy, said she would be a “hard no” on the vote to open debate, known as the Rule, because the package of bills continues to provide at least $300 million for the war in Ukraine.

Other hard-right conservatives and allies of Trump may follow her lead.

“Now you have a couple of new people thinking about voting against the Rule," said Rep. Ken Buck, R-Colo., referring to the upcoming procedural vote.

Once a holdout himself, Buck told reporters at the Capitol he would be voting for the package, but he's not sure McCarthy will have enough for passage. "I don’t know if he gets them back on board or not,” Buck said.

While their numbers are just a handful, the hard-right Republican faction holds oversized sway because the House majority is narrow and McCarthy needs almost every vote from his side for partisan bills without Democratic support.

The speaker has given the holdouts many of their demands, but it still has not been enough as they press for more - including gutting funding for Ukraine, which President Volodymyr Zelenskyy told Washington last week is vital to winning the war against Russia.

The hardline Republicans want McCarthy to drop the deal he made with Biden and stick to earlier promises for spending cuts he made to them in January to win their votes for the speaker's gavel, citing the nation's rising debt load.

Republican Rep. Matt Gaetz of Florida, a key Trump ally leading the right flank, said on Fox that a shutdown is not optimal but “it's better than continuing on the current path that we are to America's financial ruin.”

Gatez, who has also threated to call a vote to oust McCarthy from his job, wants Congress to do what it rarely does anymore: debate and approve each of the 12 annual bills needed to fund the various departments of government - typically a process that takes weeks, if not months.

“I’m not pro-shutdown,” he said. But he said he wants to hold McCarthy “to his word.”

Even if the House is able to complete its work this week on some of those bills, which is highly uncertain, they would still need to be merged with similar legislation from the Senate, another lengthy process.

Meantime, senators have been drafting a temporary measure, called a continuing resolution or CR, to keep government funded past Saturday, but have run into trouble trying to tack on Biden's request for supplemental funding for Ukraine. They face resistance from a handful of Republicans to the war effort.

A Senate aide said talks would continue through the night. And a spokesperson for the White House Office of Management and Budget said the administration would continue to work with members of both parties in Congress to secure supplemental funds and ensure efforts to support Ukraine continue alongside other key priorities like disaster relief.

With just days remaining before a shutdown, several of the holdouts say they will never vote for any stopgap measure to fund the government as they push for Congress to engage in the full-scale debate.