A funny thing happened on the way to a bipartisan agreement to fund US government operations and avoid a partial shutdown this week.

Conservatives in Congress – encouraged by tech multi-billionaire Elon Musk – balked.

Republicans tried to regroup on Thursday afternoon, offering a new, slimmed-down package to fund the government. That vote failed, as 38 Republicans joined most Democrats in voting no.

All this political drama provides just a taste of the chaos and unpredictability that could be in store under unified Republican rule in Washington next year.

The man at the centre of this week's drama holds no official government title or role. What Elon Musk does have, however, is hundreds of billions of dollars, a social media megaphone and the ear not just of the president of the United States but also rank-and-file conservatives in Congress.

On Wednesday morning, the tech tycoon took to X, which he purchased for $44bn two years ago, to disparage a compromise that Republican Speaker of the House Mike Johnson had struck with Democrats to temporarily fund US government operations until mid-March.

As the number of his posts about the proposed agreement stretched into triple digits, at times amplifying factually inaccurate allegations made by conservative commentators, opposition to the legislation in Congress grew.

And by Wednesday evening, Donald Trump – perhaps sensing that he needed to get in front of the growing conservative uprising - publicly stated that he, too, opposed the government funding bill.

He said it contained wasteful spending and Democratic priorities, while also demanding that Congress take the politically sensitive step of raising – or even doing away with - the legal cap on newly issued American debt that the US would reach sometime next summer.

Support for the stopgap spending bill then collapsed, forcing Johnson and his leadership team to scramble to find an alternative path forward. As they did, Musk celebrated, proclaiming that "the voice of the people has triumphed".

It may be more accurate, however, to say that it was Musk's voice that triumphed.

On Thursday afternoon, Republicans unveiled a new proposal that suspended the debt limit for the first two years of Trump's second term, funded the government until March and included some disaster relief and other measures included in the original funding package.

But Musk's involvement may not land well with some legislators. Democrats in the chamber joked about "President Musk", while even a few Republicans publicly grumbled.

"Who?" Pennsylvania Republican Glenn Thompson responded when asked about Musk. "I don't see him in the chamber."

Musk may have been the instigator, but this latest congressional funding crisis reveals what has been – and is likely to continue to be – an ongoing challenge for the narrow Republican majority in the House of Representatives.

For two years, Republicans in the chamber have grappled with keeping a united front amidst a party populated, at least in part, by politicians with an active contempt for the government they help to run.

Internal divisions delayed Kevin McCarthy's election as speaker of the House in January 2022 and led to his removal – a first in American history – the following year. Johnson ultimately replaced him, but only after weeks of leaderless limbo.

Some Republicans had hoped that with Trump's election, members of their majority, which will become even slimmer when the new Congress is sworn in next month, would be more willing to march in lockstep to support the new president's agenda. And some are.

"I think President Trump pretty much laid out the plan, so I don't know what the discussions are about," Florida Congresswoman Anna Paulina Luna told reporters after internal Republican meetings on Thursday afternoon.

What this week has revealed, however, is that the president-elect may not always offer the legislature the clear, consistent direction it requires.

His insistence on raising the debt limit, for instance, caught many in his own party by surprise. And outside influences, such as from Musk or others, could inject extra instability into the process.

If Republicans aren't able to reach near unanimity in the House, they will have to find ways to win over Democrats if they want to achieve any kind of legislative success. And what this week showed (once again) is that the kind of political compromises necessary could prompt a greater number of Republican defections.

Trump's party will be challenged to effectively govern on its own – but it also may not be able to tolerate governing with the help of Democrats.

If there is no political equilibrium in the chamber, it would put Trump's more ambitious legislative priorities at risk before he even takes office.

Republicans may yet find a way to avoid a lengthy government shutdown through a temporary budget resolution, even though the first round of pressure from Trump resulted in an embarrassing failure to win enough support within his own party.

For Johnson, however, the damage may have already been done. His authority over House Republicans has been undercut – first by Musk and then by Trump - just a few weeks before he stands for re-election as speaker of the House.

Already one Republican, Thomas Massie of Kentucky, has said he will not support Johnson's re-election. Others, including members of Johnson's own leadership team, have been noncommittal. Marjorie Taylor Greene, the firebrand Georgia congresswoman who unsuccessfully pushed to remove Johnson in May, suggested Musk become speaker.

Meanwhile, Trump – the one man who could throw Johnson a lifeline – has been equivocal, telling Fox News that Johnson could "easily" remain speaker if he "acts decisively and tough".

Decisiveness may not be enough, however, when every direction for the speaker appears to lead to a dead end.