Trump tweeted Sunday that the instant bestseller -- which paints him as disengaged, ill-informed and unstable, with signs of serious memory loss -- was a "Fake Book, written by a totally discredited author."

A day earlier, seeking to refute Wolff's suggestion that he lacked stability, Trump called himself a "very stable genius."

Senior Trump policy adviser Stephen Miller treated the book derisively while insisting that his boss was in fact "a political genius," in an interview with CNN on Sunday.

Wolff, Miller said, "is a garbage author of a garbage book." He assailed Trump's former chief strategist Steve Bannon, reportedly a key source for the author, as "vindictive" and "out of touch with reality."

Almost daily, he said, White House aides would say, "We're not at a 25th Amendment level yet."

- 'Not going to succeed' -

Nikki Haley, the US ambassador to the United Nations, rejected that notion, telling ABC that no one at the White House "questions the stability of the president." She suggested that Wolff was someone who would "lie for money and for power."

Meantime, CIA director Mike Pompeo, appearing on Fox News Sunday, insisted that Wolff's portrayal of Trump was "just pure fantasy."

Far from being detached and unable to deal with complex policy issues, Pompeo said, "The president is engaged, he understands the complexity, he asks really difficult questions of our team at the CIA." He described Trump as an "avid consumer" of the agency's intelligence.

Pompeo added that Trump was "completely fit," saying it was "ludicrous" to suggest otherwise.

- 'Hysterical coverage' -

Miller called Tapper "condescending" and "snide," and accused CNN of engaging in "negative anti-Trump hysterical coverage" and "spectacularly embarrassing false reporting."

The two men repeatedly spoke over each other before Tapper declared, "I think I've wasted enough of my viewers' time. Thank you, Stephen," then turned away from Miller -- who was still talking -- to tersely announce the next guest.

Miller was not treated kindly in Wolff's book. The author wrote that Miller "was supposed to be the house intellectual but was militantly unread. He was supposed to be a communications specialist, but he antagonized almost everyone."

Miller's combative performance on CNN got a thumbs up from his boss.

"Jake Tapper of Fake News CNN just got destroyed in his interview with Stephen Miller of the Trump Administration. Watch the hatred and unfairness of this CNN flunky!" Trump tweeted after the segment aired.