WASHINGTON >> President Donald Trump launched a scathing attack on former top adviser Steve Bannon, responding to a new book that portrays Trump as an undisciplined man-child who didn’t actually want to win the White House and quotes Bannon as calling his son’s contact with a Russian lawyer “treasonous.”

Hitting back via a formal White House statement rather than a more typical Twitter volley, Trump insisted Bannon had little to do with his victorious campaign and “has nothing to do with me or my Presidency.”

“When he was fired, he not only lost his job, he lost his mind,” Trump said Wednesday.

It was a blistering attack against the man who helped deliver the presidency to Trump, spurred by an unflattering new book by writer Michael Wolff that paints Trump as a leader who doesn’t understand the weight of the presidency and spends his evenings eating cheeseburgers in bed, watching television and talking on the phone to old friends.

Late Wednesday, Trump attorney Charles Harder threatened legal action against Bannon over “disparaging statements and in some cases outright defamatory statements.”

Harder sent Bannon a letter saying the former Trump aide violated confidentiality agreements by speaking with Wolff. The letter demanded Bannon “cease and desist” any further disclosure of confidential information. Bannon did not immediately respond to a request for comment.

Harder on Thursday threatened legal action against Wolff and publisher Henry Holt and Co. in an attempt to halt the book’s publication or release of further excerpts. Neither immediately responded to requests for comment.

Trump has a history of threatening to sue when he doesn’t like something but rarely acts on those threats.

White House aides were blindsided when early excerpts from “Fire and Fury: Inside the Trump White House” were published online by New York magazine and other media outlets ahead of the Jan. 9 publication date.

The release left Trump “furious” and “disgusted,” said White House Press Secretary Sarah Huckabee Sanders, who complained that the book contained “outrageous” and “completely false claims against the president, his administration and his family.”

Asked what specifically had prompted the president’s fury with Bannon, she said: “I would certainly think that going after the president’s son in an absolutely outrageous and unprecedented way is probably not the best way to curry favor with anybody.”

In the book, an advance copy of which was provided to The Associated Press, Bannon is quoted as describing a June 2016 meeting at Trump Tower between Donald Trump Jr., Trump campaign aides and a Russian lawyer as “treasonous” and “unpatriotic.” The meeting has become a focus of federal and congressional investigators.

Bannon also told Wolff the investigations into potential collusion between Russia and Trump campaign officials would likely focus on money laundering.

“They’re going to crack Don Junior like an egg on national TV,” Bannon was quoted as saying in one section that was first reported by The Guardian.

A spokeswoman for Bannon did not immediately respond to a request for a comment. Trump Jr. lashed out in a series of tweets, including one that said Andrew Breitbart, the founder of the Breitbart News site that Bannon now runs, “would be ashamed of the division and lies Steve Bannon is spreading!”

Bannon, who was forced out of his White House job last summer, was not surprised or particularly bothered by the blowback, according to a person familiar with his thinking but not authorized to speak publicly on the matter. That person said Bannon vowed on Wednesday to continue his war on the Republican establishment and also predicted that, after a cooling-off period, he’d continue to speak with Trump, who likes to maintain contact with former advisers even after he fires and sometimes disparages them.

CNN reported Bannon said on his satellite radio program Wednesday night that Trump was a “great man” after the president had blasted Bannon earlier in the day.

Sanders said Bannon and Trump last spoke in the first part of last month.

The former-and-current Breitbart News head has told associates that he believes Trump has been ill-served by some his closest allies, including eldest son Don Jr. and Jared Kushner, the president’s son-in-law. Bannon believes they have exposed Trump to the Russia probe that could topple his presidency and that Trump would be able to accomplish more without them

So far, there is no indication that Bannon is being investigated by special counsel Robert Mueller. But the House intelligence committee has invited him, along with former Trump campaign manager Corey Lewandowski, for a closed-door interview as a part of the panel’s investigation into Russian meddling in the 2016 election, according to a person familiar with the invitation.

Trump, up until Wednesday, had been complimentary of Bannon, saying in October that the two “have a very good relationship” and had been friends for “a long time.”

In the book, Bannon also speaks critically of Trump’s daughter and White House adviser, Ivanka, calling her “dumb as a brick.”

“A little marketing savvy and has a look but as far as understanding actually how the world works and what politics is and what it means — nothing,” he is quoted saying.

New York magazine also published a lengthy adaptation of the book on Wednesday, in which Wolff writes that Trump believed his presidential nomination would boost his brand and deliver “untold opportunities” — but that he never expected to win.

It says Trump Jr. told a friend that his father looked as if he’d seen a ghost when it became clear he might win. The younger Trump described Melania Trump as “in tears — and not of joy.”

The first lady’s spokeswoman, Stephanie Grisham, disputed that, saying Mrs. Trump supported her husband’s decision to run, encouraged him to do so and was happy when he won.

“The book is clearly going to be sold in the bargain fiction section,” Grisham said in a statement.

Wolff was generally granted access to the White House with a ‘blue badge” instead of the traditional press badge, giving him wide access to the West Wing, according to officials who spoke on condition of anonymity in order to discuss internal protocol. One former White House official said Wolff was known to camp out for hours in the West Wing lobby after meetings, sitting on a sofa as he waited to talk to staffers passing by.

Wolff said in an author’s note that the book was based on more than 200 interviews, including multiple conversations with the president and senior staff. But Sanders said Wolff “never actually sat down with the president” and had spoken with him just once, briefly, by phone, since Trump had taken office.

She also said the vast majority of interviews Wolff conducted with other White House officials were done at Bannon’s request.

Bannon’s comments in the book are just his latest published criticism of the president and his family. In a Vanity Fair piece late last year, he was quoted telling friends and advisers that Trump had “lost a step” since his swearing-in and was “like an 11-year-old child.”

Associated Press writer Zeke Miller contributed to this report.