FILE - In this Jan. 20, 2017, file pool photo, Steve Bannon, appointed chief strategist and senior counselor to then- President-elect Donald Trump, arrives for the presidential inauguration at the US Capitol in Washington. Trump returned fire with both barrels Jan. 3, 2018, against criticism leveled at him in a new book that says he never expected — or wanted — to win the White House, his victory left his wife in tears and a senior adviser thought his son's contact with a Russian lawyer during the campaign was "treasonous." (Saul Loeb, Pool via AP)
FILE - In this Jan. 20, 2017, file pool photo, Steve Bannon, appointed chief strategist and senior counselor to then- President-elect Donald Trump, arrives for the presidential inauguration at the US Capitol in Washington. Trump returned fire with both barrels Jan. 3, 2018, against criticism leveled at him in a new book that says he never expected — or wanted — to win the White House, his victory left his wife in tears and a senior adviser thought his son's contact with a Russian lawyer during the campaign was "treasonous." (Saul Loeb, Pool via AP)

Washington — The acrimony surrounding former White House adviser Steve Bannon’s very public break with President Donald Trump escalated on Thursday, suggesting a permanent split between the president and the pugilistic strategist who helped put him in the Oval Office. The new fissure in an already fractious Republican Party cast doubt on Bannon’s hopes to foment a movement centered on “Trumpism without Trump.”

It already has cost him a key backer. Rebekah Mercer, the billionaire GOP donor and Breitbart co-owner, issued a statement on Thursday distancing her family from Bannon.

“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 Bannon’s criticisms, laid out in an explosive new book that quoted the former aide as questioning 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.”

A parade of administration officials and allies worked to discredit Bannon as a disgruntled has-been. White House press secretary Sarah Huckabee Sanders went so far as to suggest that Bannon ought to be booted from Breitbart, the populist website he helps run.

“I certainly think that it’s something they should look at and consider,” she said.

Bannon had helped Trump form a coalition of anti-establishment Republicans, blue-collar working class and economic nationalists that launched him to the White House, but Trump had long ago grown frustrated that Bannon seemed to be overstepping his role as a staffer.

The self-appointed keeper of Trump’s nationalist flame during the president’s first six months in office, Bannon had soured on the president even before he was pushed out of the White House for feeding the perception that he was Trump’s puppeteer.

None of Bannon’s close associates was willing to speak publicly about the fallout but privately conceded that the explosive comments may forever tarnish his brand. Bannon’s political appeal had been deeply tied to the perception that he was an ally of Trump’s. Those close to Bannon feared that the connection had been permanently severed.

Bannon was preparing to launch a nonprofit organization designed to help give Trump’s brand of conservatism populism a permanent base.

It’s unclear how Bannon’s new rift with the president, and the related impact on major donors, will affect the organization, dubbed Citizens of the American Republic.