Michael Wolff, author of the explosive book about Donald Trump, says that the US president’s angry reaction to its publication proves “he might be cracking up.”

The media columnist and author of the new book, Fire and Fury: Inside the Trump White House told RTÉ’s Radio 1 in an interview that Mr Trump’s political meetings since the book’s publication last week - seen as an attempt to reboot his presidency - suggests he was “completely freaked out” by the revelations.

The book portrays a chaotic White House and details accusations from the US president’s closest aides that the former reality TV star is mentally unfit for office.

The revelations have drawn virulent denials from the White House, legal threats from the president and his counter-claim that he was a “stable genius.”

“All of this is trying to prove that he is a stable person, a sane person rather than an out-of-control, outlandish person,” Mr Wolff told RTÉ’s presenter Sean O’Rourke.

The author said the book had “in profound ways gotten under this man’s skin and rather, to my mind, than proving that he is a stable genius, it rather looks like he might be cracking up.”

Asked what was the worst thing that could happen with Mr Trump in the White House, Mr Wolff suggested that it could be a war with North Korea.

“The worse that can happen is what nobody wants to think about. Does it involve North Korea? It quite possibly could,” he said.

Mr Wolff said that the terrifying thing about the US president was that “nobody knows how bad it can be because nobody can predict what Donald Trump is going to do.”

Mortal threat

Explaining Mr Trump’s vicious attacks on the book and its author, Mr Wolff said that he thought Mr Trump saw the book “as a mortal threat to his presidency.”

Mr Trump took to Twitter to defend his reputation ....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..... — Donald J. Trump (@realDonaldTrump) January 6, 2018

....to President of the United States (on my first try). I think that would qualify as not smart, but genius....and a very stable genius at that! — Donald J. Trump (@realDonaldTrump) January 6, 2018

“I thought that this book wold make some waves I did not in any way think it would be tsunami that it has turned out to be,” he said in the interview broadcast a week after the publication of the book.

Mr Wolff said it was no secret that Mr Trump’s most senior aides believed he did not have the capacity to serve as president.

In some instances, his staff told him this directly, he said, confirming that he had tapes of people that he had interviewed to verify his reporting.

“This was the experience that I had inside this White House of everyone coming to the conclusion - and hardly a far-fetched conclusion - that Donald Trump did not have the facility to function in this job,” he said.

The author said the one thing Mr Trump was getting right in office was that “the chaos prevents him from doing anything much.”

“In the great scheme of things he has probably done much less wrong than we might have thought that he would do because he can’t get out of his own way,” said Mr Wolff, in his first Irish interview about the book.

He stood by his claim that former British prime minister Tony Blair shared a “juicy rumour” with Trump’s son-in-law Jared Kushner when they met in February 2017: that the British had the calls and communications of Trump campaign aides under surveillance.

Author Michael Wolff on the set of NBC's 'Today' show prior to an interview about his book "Fire and Fury: Inside the Trump White House". Photograph: Reuters

‘Complete fabrication’

Mr Blair has called the claim “a complete fabrication.”

Mr Wolff told RTÉ that the anecdote “gets to the heart of a very weird episode” in the White House to explain why Mr Trump accused the Obama administration of wiretapping him.

“I have just given a piece of that puzzle,” he said.

He questioned why then Mr Kushner and Mr Trump’s then chief strategist Steve Bannon, a key source of Mr Wolff’s for this book, would have travelled to CIA headquarters “on the basis of a fabrication.”

Mr Wolff denied he misrepresented Mr Bannon’s comments when he reportedly said Donald Trump Jr’s meeting with a group of Russians at Trump Tower was “treasonous.”

Mr Bannon has claimed that he was talking about Mr Trump’s former campaign manager Paul Manafort, not Mr Trump Jr.

“Absolutely, completely, without question, not,” said Mr Wolff on whether he misquoted him.

Mr Trump has said that he had never spoken to the author for his book - a claim Mr Wolff has denied, saying that he spent three hours with the president during the 2016 campaign and in the White House.

When he asked Mr Trump for access to him and his White House staff to write the book, the property developer-turned-politician thought Mr Wolff was asking for a job in his administration, the author said.

“He certainly didn’t object when I showed up at the White House and I started making appointments with the senior staff,” he said.