Donald Trump responded to questions about his mental capacity and fitness for office on Saturday, calling himself "like, really smart" and "a very stable genius"

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On Saturday, President Donald Trump responded to questions about his mental capacity and fitness by calling himself “like, really smart” and saying that he is “a very stable genius.”

In a series of Twitter messages, the 71-year-old former Celebrity Apprentice star appeared to slap back at claims made in Michael Wolff’s headline-making new book Fire and Fury: Inside the Trump White Housewhich reported that a number of White House staffers alleged Trump was “incapable of functioning in his job.”

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“Now that Russian collusion, after one year of intense study, has proven to be a total hoax on the American public, the Democrats and their lapdogs, the Fake News Mainstream Media, are taking out the old Ronald Reagan playbook and screaming mental stability and intelligence,” Trump said.

“Actually, throughout my life, my two greatest assets have been mental stability and being, like, really smart. Crooked Hillary Clinton also played these cards very hard and, as everyone knows, went down in flames. I went from VERY successful businessman, to top T.V. Star to President of the United States (on my first try),” he continued. “I think that would qualify as not smart, but genius…. and a very stable genius at that!”

White House press secretary Sarah Huckabee Sanders responded to similar questions about President Trump’s mental fitness to serve on Thursday, calling them “disgraceful and laughable” during her daily press briefing.

“If he was unfit, he probably wouldn’t be sitting there,” Sanders said. “This is an incredibly strong and good leader.”

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In Fire & Fury, Wolff writes of Trump staffers: “My indelible impression of talking to them and observing them through much of the first year of his presidency, is that they all — 100 percent — came to believe he was incapable of functioning in his job.”

Wolff also alleged that Trump has had trouble recognizing old friends in an essay about the book published in The Hollywood Reporter, an apparent hint that the president’s memory may be fading.

Back in November, Joe Scarborough — a former friend of Trump — made similar claims on MSNBC’s Morning Joe, saying that people close to the president have said he has shown early signs of dementia.

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Trump’s attorneys issued Wolff’s publisher a cease and desist letter earlier in the week to prevent the publication of the book. Instead, the book — which was originally slated for publication Jan. 9 — was published on Friday.

It’s gone on to place No. 1 on Amazon’s best-seller list and people are checking it out from libraries as fast as Harry Potter.

Michael Wolff's Book On Trump Administration Released Early Due To Demand
Copies of Michael Wolff’s Fire and Fury: Inside the Trump White House
| Credit: Justin Sullivan/Getty Images

Late Friday evening, Trump went on a Twitter spree zeroing in on the the author, whom he called “a total loser.”

“Michael Wolff is a total loser who made up stories in order to sell this really boring and untruthful book,” the commander-in-chief wrote.

On Thursday, Trump also tweeted that he did not allow Wolff access to the White House. (Wolff has denied those claims.)