Has Donald Trump finally split the Republican party?

After four years of norm-shattering rule, Donald Trump appears close to doing the one thing observers have long predicted but that has not yet come to pass: splitting the Republican party.

Related: America braced for final month of madness as Trump show nears its end

With Trump staring at the prospect of only a few more weeks in the White House, significant segments of the party are finally breaking with a president to whom they have hitherto displayed almost unwavering loyalty. Furthermore, Trump’s stoking of division in his own party has even succeeded in uniting warring factions among his opponents.

Responding on Wednesday night to the president’s bombshell threat to veto the $900bn Covid relief and stimulus bill, Democratic leaders and members of the progressive House “Squad” – otherwise at each other’s throats – welcomed Trump’s demand for increased direct payments to individual Americans.

“Let’s do it!” said Speaker Nancy Pelosi.

“We can pass $2k checks this week,” wrote Representative Alexandria Ocasio-Cortez.

Somewhere on Capitol Hill, presumably, Republican Senate majority leader Mitch McConnell buried his head in his hands.

‘Send me a suitable bill, or else’

Predictions that Trump will wreck and split the Republican party have been rife since 2015, when he wrecked and split – and won – the race for the presidential nomination. While the party remains whole, and an official split will be a surprise, it has now descended into internecine strife, Trump loyalists fighting for the lost cause of a second term while others seek to adjust to life back in opposition.

Trump maintains a strong hold on the hard-right Republican base, on a large part of the House delegation who owe their seats to that base and on influential senators. The penalty for apostasy is clear: a primary from the right or, as rumour has it in the case of the Florida senator Marco Rubio, a challenge from Trump’s own daughter.

But in contrast to the zeal of the Maga-fuelled legions, in the Senate the party establishment has now rejected Trump’s increasingly wild attempts to hold on to power while negotiating the Covid deal which stoked Tuesday night’s extraordinary display of presidential petulance from the White House podium.

In his video message, Trump bemoaned spending commitments in the relief deal and demanded Congress “send me a suitable bill, or else the next administration will have to deliver a Covid relief package. And maybe that administration will be me.”

It won’t, even if Trump’s allies in the House and Senate go through with planned challenges to the electoral college result in Congress on 6 January. Democrats who control the House will ensure the result is certified there, while McConnell and his deputies assure passage in the Senate.

But if such challenges can only be performative, they will be politically beneficial for everyone except the Republican establishment which will help to beat them down. Trump’s refusal to accept defeat, not to mention the vicious fire he and his allies have directed at McConnell since the senator recognised Joe Biden’s win, is damaging the president’s own party.

A day before the electoral college result is certified, two run-off elections in Georgia will decide control of the Senate. Early voting has started. Seeking to hold on to the party’s best hope of thwarting Biden’s agenda, McConnell needs a united front. Such is Trump’s refusal to accept party discipline or political reality, that has become impossible.

Georgia’s two sitting senators, Kelly Loeffler and David Perdue, have thrown in their lots with Trump. That means supporting his claim the presidential election was rigged, which the party establishment fears could suppress Republican turnout.

‘A different course’

On CNN last weekend, the Utah senator and 2012 presidential nominee Mitt Romney, a frequent Trump critic, was asked if he “still recognised the Republican party”.

“The party has taken a different course than obviously the one that I knew as a younger person,” Romney said, adding that his Republican party stood for leading abroad while “balancing the budget” at home.

“And we believed that character was essential in the leaders that we chose. We’ve strayed from that. I don’t see us returning to that for a long time.”

The remark about character was pointed. Romney went on to describe a battle to succeed Trump at the top of the party that promises to be as life was to Thomas Hobbes: nasty and brutish, if long-term rather than short.

“As I look at the 2024 contenders,” Romney said, “most of them are trying to become as much like Donald Trump as they can be. Although I must admit that his style and schtick, if you will, is difficult to duplicate.”

Of necessity, ambitious senators such as Josh Hawley of Missouri, Tom Cotton of Arkansas and Ted Cruz of Texas would have taken that as a compliment – but also a warning. Trump is reportedly likely to announce his own candidacy for 2024 not long after removal from office.

“I represent a very small slice of the Republican party today,” Romney continued, “but you know everybody has to stand up for what they believe. And I believe my colleagues are doing what they think is right.”

For some Republicans, Trump has already proven too much.

Outside Congress, the Never Trumpers of the Lincoln Project, the Bulwark and other groups fought for Biden while former Republican voters helped turn Georgia and Arizona blue. Inside Congress, a few have taken a stand. The common way out is to retire but two House members from Michigan, Justin Amash last year and Paul Mitchell this, found the courage to publicly leave their party.

Such numbers are small. The party remains in one piece. Whether it stays so remains to be seen. In the brewing fight, those ranged against Trump are not ready to quit.

Writing for the Washington Post in November, long before Trump’s refusal to concede defeat mutated into considerations of martial law, the conservative columnist Jennifer Rubin said the US effectively has “three parties now: the Democratic party, the Anti-Democracy Trump party and the Pro-Democracy Republican party.”

Rubin advocated a bipartisan effort to restore balance, writing: “Once the Anti-Democracy Trump party is marginalised we might have functional government again. The Democratic party and the Pro-Democracy Republican party should put their heads together and devise a strategy to bring that about – quickly, and certainly before 2024.”

Romney has disappointed Democrats before, not least over the appointment of supreme court justice Amy Coney Barrett. But he seems to be up for the fight.

“I think I’m more effective in the Republican party, continuing to battle for the things I believe in,” he said, when asked if he would leave. “I think ultimately the Republican party will return to the roots that have been formed over the last century.

“Hopefully people will recognise we need to take a different course than the one we’re on right now.”