The Republican Party's long-simmering internal divisions under President Donald Trump, temporarily papered over when his surprise 2016 win gave the party control of federal government, have erupted into open political warfare – and the newest insurgents from the establishment are fighting their former allies.

A day after a top West Wing staffer urged heavyweight donors to close their wallets to Capitol Hill Republicans until Congress kick-starts Trump's stalled agenda, Politico reports that a group of wealthy conservatives who have long supported Republican candidates and causes told Senate Majority Leader Mitch McConnell, to his face: The GOP won't get any campaign contributions until he gets a legislative win.

"Anybody who was there knew that I was not happy. And I don't think anybody was happy. How could you be?" oil magnate Thomas Wachtell told Politico. He was describing a recent, exclusive Los Angeles fundraising dinner with about 10 deep-pocketed contributors and McConnell as the guest of honor.

"You're never going to get a more sympathetic Republican than I am," said Wachtell, a Los Angeles billionaire who is the chairman of the W.M. Keck Foundation. Politico reports he has given tens of thousands of dollars to Senate Republicans and more than $2,000 to McConnell, but recently stopped donating in protest of GOP inaction.

"I'm sick and tired of nothing happening," he said.

The revelation, however, follows reports that Nick Ayers, Vice President Mike Pence's chief of staff, told a different group of conservative fundraisers that they should help launch a "purge" of the party establishment if things don't change. The logic, he said, is simple: Legislative failures have put Republicans on a path to losing their majorities in the House and Senate in the 2018 midterms, so Trump needs White House loyalists – not ineffective turncoats – to make a stand on Capitol Hill.

If he were in their shoes, "I would not only stop donating, I would form a coalition of all the other major donors, and just say two things," Ayers reportedly told the group. "We're definitely not giving to you, No. 1. And No. 2, if you don't have this done by Dec. 31, we're going out, we're recruiting opponents, we're maxing out to their campaigns, and we're funding super PACs to defeat all of you."

Experts say the outbreak of bad news is the latest sign of an imminent confrontation between mainstream Republicans, who rode Tea Party anger to majorities in both houses of Congress, and staunch backers of Trump, an outsider politician elected on a promise to upend the Washington establishment.

The developments also ups the ante for Republicans who, despite controlling the House, the Senate and the Oval Office, failed to repeal Obamacare – job one on the GOP's to-do list – and will probably struggle to pass tax reform, which has suddenly become do-or-die legislation.

That means there's going to be more finger-pointing, backbiting and power moves on the right, experts predict. Unless the party's fortunes reverse, and in a hurry, the Republicans will be starved of a crucial resource – big campaign cash – ahead of the midterm elections, Trump almost certainly will face a challenger for the Oval Office and the future of the Party of Lincoln is anything but certain.

"It's one more indication that there's a serious civil war in the Republican Party," says Elaine Kamarck, a senior fellow at the nonpartisan Brookings Institute, a Washington, D.C., think tank.

"It's also a sign, I think, of their desperation over the situation Trump is in," she says. "I think they're just having trouble all over. This is sort of the impolitic outburst that tells you how high the tensions really are."

The ugly headlines, and Ayers' warning shot in particular, have some Republican lawmakers fuming, accusing Pence's chief of staff of throwing sand in the gears of the GOP's delicate tax reform negotiations.

Though Ayers said he was speaking for himself, the suggestion that donors turn off the money spigot for GOP incumbents comes not from a rogue outsider but from the top adviser to Pence, an old-school Republican who served six terms in the House and whom Trump picked as veep for his connections on Capitol Hill.

That dynamic – a West Wing operative who works for an influential establishment figure, telling major donors to kick out incumbents and fund only hard-right Trump loyalists – opens up a politically dangerous front in long-simmering hostilities between Trump and Congress.

"I enjoy it when Republicans fight against Democrats more than when Republicans fight against other Republicans. I also think it's more constructive," Senate Majority Whip John Cornyn, R-Texas, told The Washington Examiner.

Norm Ornstein, a senior fellow at the American Enterprise Institute, predicts the party is in for a day of reckoning, sooner rather than later.

"It does not bode well for party unity," says Ornstein, co-author of "One Nation After Trump: A Guide for the Perplexed, the Disillusioned, the Desperate, and the Not-Yet Deported." The Republican civil war, he says, will be a long, drawn-out, metaphorically bloody conflict between Trump's insurgents and McConnell's traditionalists, and it's hard to tell which side might win.

"There is no end game here. A lot of this is endemic to the party, where loyalty is defined in ways that might be different for Dems and for you and me," says Ornstein. "It's in part I think Trump's personality, which is, 'If you're not with me you're automatically against me.'"

It's no secret that Trump and McConnell, in particular, have been at odds for months, due in part to Trump's outsider status as a rookie politician pledged to upend Washington and McConnell's mastery of the insider's game played in Congress. The conflict, however, went from back-room sniping to open warfare after Trump publicly blamed McConnell for failing to repeal the Affordable Care Act – the president's signature campaign promise, but McConnell's burden to carry out.

Unlike Trump, McConnell and his House counterpart, Majority Leader Paul Ryan, have kept a unified GOP front and resisted criticizing Trump, despite fissures – and a mob of angry donors – that seem to grow by the day. Yet analysts say the bigger factor of the dysfunction is the president himself.

"If I had to put numbers on it, it's, like 60 percent due to Trump and his inexperience, and 40 percent due to the fact the Republican party was in turmoil coming in," says Kamarck, noting growing fissures between the party mainstream and Trump's far-right base. "If they hadn't been in trouble, they wouldn't have nominated Trump in the first place," handing the party leadership to a celebrity billionaire with no legislative experience.

"Ironically," she continued, "he can't negotiate. This is 'The Art of the Deal' guy. But he's shown no ability to negotiate in the political sphere." Now, she explains, lawmakers are on edge because Republicans have had control two of the three branches of the federal government for nearly a year, but neither Congress nor the White House have anything to show for it.

After Ayers' speech Tuesday, Rick Wilson, a Republican consultant and frequent Trump critic, logged into Twitter and served up some tough love to Pence's chief of staff. Lawmakers' dIsloyalty to Trump, he said, isn't the issue, and talk of a purge distracts from the real problem.

"I like Nick Ayers. He's a smart, decent guy. But this whole purge pitch is fabulously dumb," Wilson wrote in a 19-part Tweetstorm. "The problems the GOP faces in 2018 have *zero* to do with opposition to Donald Trump and *everything* to do with the utter flaming sh**show of an inept, corrupt, disloyal, intellectually vacant White House."

Moreover, "The GOP races where [incumbents] are either in trouble, or retiring have problems because Trump is poison to everyone outside his base," Wilson wrote, noting that Trump's endorsement couldn't save interim Alabama Sen. Luther Strange, an establishment candidate who lost decisively to Roy Moore, a far-right conservative, in the state's Republican primary.

Indeed, two highly-conservative former White House aides, Steve Bannon and Sebastian Gorka, openly campaigned for Moore, while McConnell shoveled millions in campaign donations to Strange, adding further intrigue to the Republicans' schism.

Wilson elaborated in an email interview with U.S. News, writing that "purges never work out as planned … the GOP already pushed out almost any voice of opposition to Trump, but parties only grow by addition." Congress may need a big win to placate donors, he says, but "Does Trump have the power to purge them if they don't meet all of his fantasyland ideas like the Wall? Absolutely not."

There's the rub, says Kamarck: Trump promised far more than he could realistically deliver, and mainstream Republicans – who similarly stoked tea party anger at the Affordable Care Act to win the House and the Senate in 2010 – are struggling to keep that restless faction in line.

"They've nominated somebody who's not really up to the job, as we've seen," she says. "They've got a problem with their candidate and they've got deep problems within themselves," principally "schizophrenia" between the base's love of federally funded programs like Social Security and Medicare and their anger at politicians who won't cut government spending.

As she sees it, Kamarck says, Ayers' call for a purge makes for good theatrics, but if it happens it won't head off the GOP's imminent collapse under Trump. The party will become a permanent minority, or undergo sweeping change, she says, in any one of three increasingly likely scenarios.

"If they get clobbered in the midterms, if [Special Counsel Robert] Muller manages to tie Russian interference to the Trump presidential campaign, and if Trump continues to be the kind of erratic, chaotic, misspoken president we've seen so far," she says. Any or all of those developments, she adds, will almost certainly lead to a Republican primary challenger for Trump in 2020.

"Whoever wins that challenge is going to redefine the Republican Party," Kamarck says. "It's been building for some time" as the party became increasingly strident and divisive on civil rights and government spending and lackluster on job creation and economic growth.

Ornstein agreed, adding that the GOP's internal divisions are directly related to its strategic decision to capitalize on an angry electorate. Lawmakers' failure to deliver, he said, reminded him of a quote he attributed to President John F. Kennedy.