Top congressional leaders are heading to the White House Monday afternoon to meet with President Donald Trump in a last-ditch effort to avert a government shutdown -- but as a stalemate persists just one day from the deadline, a shutdown seems nearly inevitable barring an unexpected breakthrough.

Hours before the meeting, White House press secretary Karoline Leavitt said that there's "nothing to negotiate" with bipartisan congressional leadership Monday -- as the administration continues to push lawmakers to pass a short-term funding bill known as a clean clean continuing resolution.

"Our message and what we want out of this is very simple: The president wants to keep the government open. He wants to keep the government funded. There is zero good reason for Democrats to vote against this clean continuing resolution,” Leavitt told reporters at the White House Monday morning. “The president is giving Democrats one last chance to be reasonable today.”

Lawmakers from both sides of the aisle are digging in ahead of the Tuesday night deadline – with Democrats maintaining their posture that they will not vote to keep the government open without lofty health care concessions. Those demands include restoring $1 trillion in Medicaid cuts passed into law this summer on top of a permanent extension of the Obamacare subsidies set to expire at the end of the year, saving health insurance for 3.8 million people at a cost of $350 billion over the next decade, according to the Congressional Budget Office.

"House Democrats, Senate Democrats are in lockstep," House Minority Leader Hakeem Jeffries told reporters Monday morning at the Capitol. "We're headed into the meeting to have a good faith negotiation about landing the plane in a way that avoids a government shutdown but does not continue the Republican assault on the health care of the American people."  

On NBC's "Meet the Press," Senate Minority Leader Chuck Schumer said he hopes the meeting is focused on "serious negotiation."

"We need a serious negotiation. Now, if the president at this meeting is going to rant, and just yell at Democrats, and talk about all his alleged grievances, and say this, that, and the other thing, we won't get anything done. But my hope is it'll be a serious negotiation," Schumer said on Sunday.

The meeting marks the first bicameral, bipartisan congressional leadership face-to-face meeting of Trump’s second term -- and comes after a previously-scheduled meeting last week was nixed by the president after he said he reviewed the Democratic proposal and judged that a meeting would not be productive. 

"Republicans control the House and the Senate, and as a Republican president, if the government shuts down, it's because Republicans want to shut the government down," Jeffries said.

A meeting was agreed to after Schumer implored Senate Majority Leader John Thune for help getting through to Trump, according to a Schumer aide -- though Jeffries seems unmoved by the prospect of drawn-out negotiations. 

Last week, the White House issued guidance to federal agencies that they should consider executing a reduction in force for federal employees whose jobs are not deemed essential to government operations -- a move intended to increase pressure on Democrats who have a stated goal to protect a federal workforce that’s already been slashed by the Trump administration. 

While House Republicans passed a stop-gap measure to keep the government open through Nov. 21, the measure has stalled in the Senate, where at least seven Democrats must vote for any measure that staves off a shutdown.

Republicans crafted a "clean" seven-week stop-gap bill in order to create more time for congressional appropriators to work through regular order: 12 separate full-year funding bills. Congress has not passed all 12 appropriations bills through regular order since 1997, and the task has only been completed four times since 1977 when current budget rules took effect.

Speaker Mike Johnson maintained over the weekend that passing the short-term continuing resolution is "buying a little time" for the regular appropriations process. 

"The Obamacare subsidies is a policy debate that has to be determined by the end of the year, Dec. 31 -- not right now, while we're simply trying to keep the government open so we can have all these debates," Johnson said on CNN on Sunday. 

The federal government has shut down due to a lapse in appropriations 10 times since 1980, with the longest shutdown, 35 days, occurring during the first Trump administration.