Michael Wolff, author of the bestselling Fire and Fury: Inside the Trump White House, told the BBC on Saturday that his book will “end this presidency” and force President Donald Trump out of office.

“The story that I’ve told seems to present this presidency in such a way that it says he can’t do his job, the emperor has no clothes. And suddenly, everywhere, people are going ‘Oh my God, it’s true, he has no clothes.’ That’s the background to the perception and the understanding that will finally end this — that will end this presidency,” Wolff said.

Wolff’s comments to the BBC reinforce what he told NBC’s Today show on Friday morning, when he said that his book shows that Trump “cannot do this job.”

He told the BBC that his sources had concluded, “No, this man can’t function in this job as president. He may have been elected president, but that does not turn him into president.”

Wolff added: “I think he’s intellectually incapable of being President of the United States.” He also described the president as “ineffectual,” incapable of passing legislation, implementing policy, or producing regulations.

The book echoes arguments made by Democrats and NeverTrump Republicans that the president could, or should, be removed under the 25th Amendment to the U.S. Constitution (emphasis added):

Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.

President Trump fired back on Saturday, tweeting that he was a “very stable genius.”

Trump tried, in vain, to block publication of the book on Thursday, as his lawyers sent cease-and-desist letters to Wolff and his publisher ahead of an accelerated release date on Friday. That action only propelled sales higher, as bookstores quickly sold out of print copies.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He was named to Forward’s 50 “most influential” Jews in 2017. He is the co-author of How Trump Won: The Inside Story of a Revolution, is available from Regnery. Follow him on Twitter at @joelpollak.