The acrimony surrounding former White House adviser Steve Bannon's very public spat with Donald Trump is escalating, suggesting a permanent split between the US president and the strategist who helped put him in the Oval Office.
The new fissure in an already fractious Republican Party cast doubt on Mr Bannon's hopes of fomenting a movement centred on "Trumpism without Trump".
It has already cost him a key backer - billionaire donor and Breitbart co-owner Rebekah Mercer issued a statement distancing her family from him.
"I support President Trump and the platform upon which he was elected," she said. "My family and I have not communicated with Steve Bannon in many months and have provided no financial support to his political agenda, nor do we support his recent actions and statements."
White House officials described the president as furious at Mr Bannon's criticisms, laid out in an explosive new book which quotes the former aide as questioning Mr Trump's competence and describing a June 2016 meeting at Trump Tower between Donald Trump Jr, Trump campaign aides and a Russian lawyer as "treasonous" and "unpatriotic".
On Twitter on Thursday night, Mr Trump said the book was full of "lies, misrepresentations and sources that don't exist". He also came up with a new nickname for Mr Bannon: "Sloppy Steve".
A parade of administration officials and allies worked to discredit Mr Bannon as a disgruntled has-been. White House press secretary Sarah Huckabee Sanders went so far as to suggest that he ought to be booted out of Breitbart, the populist website he helps to run.
"I certainly think that it's something they should look at and consider," she said.
I authorized Zero access to White House (actually turned him down many times) for author of phony book! I never spoke to him for book. Full of lies, misrepresentations and sources that don’t exist. Look at this guy’s past and watch what happens to him and Sloppy Steve!— Donald J. Trump (@realDonaldTrump) January 5, 2018
Mr Bannon had helped Mr Trump form a coalition of anti-establishment Republicans, blue-collar working class and economic nationalists that launched him to the White House, but Mr Trump had long ago grown frustrated that Mr Bannon seemed to be overstepping his role.
The self-appointed keeper of Mr Trump's nationalist flame during the president's first six months in office, Mr Bannon had soured on the president even before he was pushed out of the White House for feeding the perception that he was Mr Trump's puppeteer.
None of Mr Bannon's close associates was willing to speak publicly about the fallout but privately conceded that the explosive comments may forever tarnish his brand.
Mr Bannon's political appeal had been deeply tied to the perception that he was an ally of Mr Trump. Those close to Mr Bannon feared that the connection had been permanently severed.
Mr Bannon was preparing to launch a non-profit organisation designed to help give Mr Trump's brand of conservative populism a permanent base. It is unclear how the new rift, and the related impact on major donors, will affect the organisation, dubbed Citizens of the American Republic.
Current and former White House officials said Mr Bannon had miscalculated by attacking the president and his family. Much of his political clout, they argue, stemmed from the assumption that he was acting with the imprimatur of the president.
Some Trump allies also expressed satisfaction that Mr Bannon appeared to be finally cast out of the president's inner circle.
"Bannon has no contingent," former Republican House Speaker Newt Gingrich said on Wednesday between media interviews to defend Mr Trump. On Thursday, Mr Gingrich echoed Mr Trump's charge that Mr Bannon had "lost his mind".
Republican Senate Majority Leader Mitch McConnell, a longtime punchbag for Mr Bannon, revelled in the row. "I'd like to associate myself with what the president had to say about Steve Bannon yesterday," he said mischievously.
Since leaving the White House, Mr Bannon has spent much of his time courting donors to help finance his self-declared war on the Republican establishment.
He vowed to find Republican challengers for virtually every Republican senator seeking election this autumn, chiefly for the purpose of electing candidates who would remove Mr McConnell as majority leader.
Mr Bannon publicly backed conservative challengers in Arizona, Nevada, Wisconsin, Mississippi and New York, where House challenger Michael Grimm issued a statement denouncing the ex-adviser's comments as "baseless attacks" that were "beyond disturbing".
Others who have received boosts from Mr Bannon, including Arizona Senate candidate Kelli Ward and potential Mississippi Senate challenger Chris McDaniel, were more circumspect, wary of alienating either faction of the party's insurgent grassroots.
Mr Bannon's political standing was already weakened after he went all out last month to support failed Alabama Senate candidate Roy Moore despite multiple allegations of sexual misconduct against him
Doubling down on Mr Moore left Mr Bannon politically "incapacitated", said Steven Law, president and chief executive of the super PAC led by Mr McConnell.
"The only concern left was whether the president might give Bannon a temporary lease on life," he said. "But this repudiation was so methodical and so absolute that it really slams the door on that."
White House aides have tried to look past other loaded comments from Mr Bannon in recent months while seeking to marshal his political following on the president's behalf.
But they warned his allies over the last 24 hours that Mr Trump was unlikely to ever take his calls again. However, there are few absolutes in Mr Trump's orbit, White House aides acknowledge, and he has been known to bury the hatchet with those he perceived to have wronged him.
Some Trump allies even encouraged him to welcome Mr Bannon back into his good graces.
"You can either excise him or shun him, which I don't think is the best recommended strategy, or tell him to knock it off and bring himself back into the fold," former White House communications director Anthony Scaramucci said on MSNBC.
Mr Trump coolly noted on Thursday that his full-throated counter-assault appeared to have its desired effect on Mr Bannon.
"He called me a great man last night," the president said, referring to Mr Bannon's radio show appearance. "He obviously changed his tune pretty quick."
Michael Wolff's book, Fire And Fury: Inside The Trump White House, quickly shot to the top of Amazon's best-seller list, and the publisher brought its release date forward by four days, to Friday.