Washington DC - President Donald Trump meets key congressional Republicans and Democrats at the White House on Monday, hoping to revive stalled spending negotiations on the eve of a looming US government shutdown.

Without Congress passing a bill to fund federal operations before midnight Tuesday night, the government will partially close up shop – and plunge Washington into a new round of political crisis.

A government shutdown would see non-essential operations grind to a halt, hundreds of thousands of civil servants temporarily left without pay, and the payment of many social safety net benefits disrupted.

Such shutdowns are deeply unpopular in the United States, and Democrats and Republicans alike try to avoid the scenario – while blaming the other camp should such a closure arise.

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But with barely 36 hours to go before the deadline, each side is digging in its heels, and the threat of a shutdown has swelled.

The White House is upping the ante by threatening to fire large numbers of civil service workers, rather than the usual practice of simply holding up their pay until a deal is reached.

Republicans have proposed to extend current funding until late November, pending negotiations on a longer-term spending plan.

But Democrats, largely powerless and reeling from Trump's dismantling of entire government departments, are seeking to make use of their rare leverage.

The party wants to see hundreds of billions of dollars in healthcare spending restored, particularly in the Obamacare health insurance program for low-income households, which the Trump administration plans to eliminate through its so-called "Big, Beautiful" budget bill passed in July.

Republican House Speaker Mike Johnson told Fox News on Sunday that Trump was "open to discussion" and "wants to operate in good faith" heading into the high-stakes White House meeting with Johnson, Senate Majority Leader John Thune, and Democratic leaders Hakeem Jeffries and Chuck Schumer.

Schumer, the Senate minority leader, characterized the meeting as a first step and told NBC News Sunday there was a need for "serious negotiation."

Jeffries, for his part, told ABC News he hopes to find "common ground" with Republicans on funding that "actually meets the needs of the American people in terms of their health, their safety, and their economic well-being."

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Although Republicans hold narrow majorities in both chambers of Congress, Senate rules require that a budget bill be passed by 60 votes out of 100, meaning that seven Democrats must be swayed to pass the Republican extension.

The White House has appeared unwilling to give an inch to the opposition, with Trump blaming his Democratic rivals for the tense showdown.

"Democrats are crazed, they don't know what they're doing," he told reporters last week.