Washington (AFP) - The United States was staring down the barrel of a holiday-period government shutdown Thursday after a late-hour intervention by Donald Trump and Elon Musk threatened efforts in Congress to keep the lights on through the New Year.

The money authorized by lawmakers to run federal agencies expires on Friday night, and party leaders had agreed on a stopgap bill – known as a “continuing resolution” (CR) – to keep operations functioning.

Debt hawks in the House of Representatives balked at what they considered an overstuffed package full of “pork” – spending unconnected to the point of the bill – but it still looked like it might pass a floor vote.

Then Musk, the world’s richest man and President-elect Trump’s incoming “efficiency czar,” bombarded his 208 million followers on X with posts trashing the text, many making false or misleading claims.

Trump eventually torpedoed the bill, threatening the reelection prospects of Republicans thinking of supporting it and demanding out of the blue that the bill increase or even scrap the country’s debt limit.

It usually takes weeks to negotiate and enact hikes in the federal borrowing cap, which since the 1940s has limited how much debt the country can rack up, but government functions are due to begin winding up at midnight going into Saturday.

The debacle offered a preview of the chaos Democrats say will attend Trump’s second term in office, and prompted questions over why a tech billionaire who is a private, unelected citizen was able to plunge Congress into crisis.

“It’s weird to think that Elon Musk will end up having paid far less for the United States Government than he did for Twitter,” prominent conservative lawyer and Trump critic George Conway posted.

- No salaries, no parks -

A shutdown would cause the closure of federal agencies and national parks, limiting public services and furloughing potentially hundreds of thousands of workers without pay over Christmas.

Senate Majority Leader Chuck Schumer accused House Republicans of being “in shambles” and cautioned that “the only way to get things done is through bipartisanship.”

With time running short, Republicans gathered to begin the seemingly impossible task of coming up with a Plan B with just hours to spare.

Republican House Speaker Mike Johnson has faced criticism from all sides for having misjudged his own members’ tolerance for the bill’s spiraling costs, and for allowing himself to have been blindsided by Musk and Trump.

He invited a parade of disgruntled Republicans into his office at the Capitol as he explored a slimmed-down funding patch that would push off a debt limit fight for two years while still including aid for farmers that Republicans had pushed for.

But Democrats, who control the Senate, have little political incentive to help Republicans and say they will only vote for the agreed package, meaning Trump’s party will have to go it alone.

This is something the fractious, divided party – which can afford to lose only a handful of members in any House vote – has not managed in any major bill in this Congress.

Asked if Democrats would support a pared-back bill with an extended borrowing cap, House Minority Leader Hakeem Jeffries offered little hope that he would bail Johnson out.

“House Democrats are going to continue to fight for families, farmers and the future of working-class Americans. And in order to do that, the best path forward is the bipartisan agreement that we negotiated,” he told reporters.

While voicing frustration over spending levels, Trump’s main objection was that Congress was leaving him to handle a debt-limit increase – invariably a contentious, time-consuming fight – rather than including it in the text.

But conservatives are generally against increasing the country’s massive borrowing – currently standing at $36.2 trillion – and multiple Republicans have never voted for a hike.