Trump Breaks With Bannon, Saying his Former Chief Strategist Has ‘Lost His Mind’

President Trump excommunicated his onetime chief strategist, Stephen K. Bannon, from his circle on Wednesday, ending for now a partnership of convenience that transformed American politics while raising questions about the future of the nationalist-populist movement they cultivated together.

The rupture came after Mr. Bannon was quoted in a new book disparaging the president’s children, asserting that Donald Trump Jr. had been “treasonous” in meeting with Russians and calling Ivanka Trump “dumb as a brick.” Mr. Trump, described by his spokeswoman as “furious, disgusted,” fired back by saying that Mr. Bannon had “lost his mind.”

In a written statement, the president excoriated Mr. Bannon as a self-promoting exaggerator who had “very little to do with our historic victory” in the 2016 presidential election and was “only in it for himself.” Rather than representing Mr. Trump’s hard-core political base or supporting his agenda to “make America great again,” Mr. Bannon was “simply seeking to burn it all down,” the president said.

While Mr. Trump had remained in touch with Mr. Bannon after pushing him out of the White House over the summer, the two now appear to have reached a breaking point. “Steve Bannon has nothing to do with me or my presidency,” Mr. Trump said. “When he was fired, he not only lost his job, he lost his mind.”

Assuming it lasts — and with Mr. Trump, nothing is ever certain — the schism could test whether he or Mr. Bannon has more resonance with the conservative base that has sustained the president through a tumultuous tenure marked by low poll numbers. Mr. Bannon’s Breitbart News has been a key weapon in Mr. Trump’s hostile takeover of the Republican Party.

Cheering the breakup on Wednesday were establishment Republicans who resent Mr. Bannon’s bomb-throwing style and his vows to wage war on incumbent lawmakers in the party primaries this year. Senate Republicans could barely contain their glee as they redistributed Mr. Trump’s statement blasting Mr. Bannon with the note “in case you missed it” and a smiling face symbol. By afternoon, candidates whom Mr. Bannon has endorsed in a handful of races faced pressure to disavow his remarks about the president’s son.

At the White House on Wednesday morning, aides who had kept a watchful eye on Mr. Bannon’s efforts to make himself a kingmaker saw an opening to finally rid themselves of him. They encouraged the president to hit back publicly, and Mr. Trump went through at least three drafts of a statement with his communications director, Hope Hicks, and other aides before sending out a final version unlike any issued by a president against a top adviser in modern times.

“Steve pretends to be at war with the media, which he calls the opposition party, yet he spent his time at the White House leaking false information to the media to make himself seem far more important than he was,” Mr. Trump said in the statement. “It is the only thing he does well. Steve was rarely in a one-on-one meeting with me and only pretends to have had influence to fool a few people with no access and no clue, whom he helped write phony books.”

A private lawyer representing Mr. Trump sent Mr. Bannon a letter on Wednesday directing him to cease and desist making derogatory comments about the president and his family and threatening a defamation lawsuit. “Legal action is imminent,” said the letter, first reported by ABC News and confirmed by a person close to the president.

Mr. Bannon declined to comment on Wednesday. But people close to him said that he believed that the president would eventually come around because Mr. Trump would need help with his base at a moment when his political muscle appeared to be on the wane. Mr. Bannon’s Breitbart site reported the contretemps but did not return fire against Mr. Trump on Wednesday.

The president was responding to comments attributed to Mr. Bannon in a new book, “Fire and Fury: Inside the Trump White House,” by Michael Wolff. The book, due out next Tuesday, was obtained by The Guardian, which first reported Mr. Bannon’s remarks, and New York magazine then posted an excerpt. A copy of the book was later obtained by The New York Times.

In the book, Mr. Bannon was quoted suggesting that Donald Trump Jr.; Jared Kushner, his brother-in-law; and Paul Manafort, then the campaign chairman, had been “treasonous” and “unpatriotic” for meeting with Russians after being promised incriminating information on Hillary Clinton during a June 2016 meeting at Trump Tower in Manhattan.

“The three senior guys in the campaign thought it was a good idea to meet with a foreign government inside Trump Tower in the conference room on the 25th floor — with no lawyers. They didn’t have any lawyers,” Mr. Bannon said after The Times revealed the meeting in July 2017, according to Mr. Wolff’s book.

“Even if you thought that this was not treasonous, or unpatriotic, or bad shit, and I happen to think it’s all of that, you should have called the F.B.I. immediately,” Mr. Bannon continued, according to the book.

He also said that the chance that Donald Trump Jr. did not introduce the Russians to his father “is zero,” a supposition rather than an assertion but one that would contradict the president’s insistence that he knew nothing about the meeting at the time.

According to Mr. Wolff, Mr. Bannon also predicted that a special counsel investigation into Russia’s interference in the 2016 election and any coordination with Trump aides would ultimately center on money laundering, an assessment that could lend credibility to an investigation the president has repeatedly called a witch hunt. “They’re going to crack Don Jr. like an egg on national TV,” Mr. Bannon was quoted as saying.

Click here to read more.