Donald Trump's Co-Author Regrets Writing The Art of the Deal and Says Trump Presidency Could 'End Civilization'

During a Monday appearance on Good Morning America, Tony Schwartz said he regrets writing the New York Times best-seller for the now GOP candidate and called Trump, 70, an “insecure” man with a short attention span.

Get push notifications with news, features and more.

“I wrote every word of it,” Schwartz said of the memoir and business advice book. “Donald Trump made a few red marks when I handed him the manuscript but that was it … I do regret writing the book.”

Schwartz told GMA that he kept silent about his personal feelings about Trump for so long because he and the businessman “had a successful experience together.”

“I never in a million years thought he would run for president,” Schwartz said. “Had I thought that 30 years ago, I wouldn’t have written the book. But for 29 years I didn’t think he would and it didn’t seem like it was important to speak out. I now feel it’s my civic duty. I have nothing to gain from this.”

Schwartz added that he has donated all royalties he’s earned from the book since Trump announced his bid for the presidency to non-profit organizations.

“It’s a terrifying thing,” he said of Trump’s presidential run. “I haven’t slept a night through since Donald Trump announced for president because I believe he is so insecure. So easily provoked and not particularly, nearly as smart as people might imagine he is.”

He added: “I do worry that with the nuclear codes he would end civilization as we know it.”

Schwartz recently spoke out about his part in the book in an article published by The New Yorker. Although he boasts a joint byline on the successful memoir, Schwartz now holds that he wrote it all – but this isn’t the first time Schwartz has tried to tell his story.

“I wrote the Art of the Deal. Donald Trump read it,” Schwartz tweeted last September, a few months after Trump announced his run for the presidency.

Related Video: Trump Officially Makes Pence His Running Mate

Schwartz told The New Yorker that he spent 18 months with Trump in 1985 to write the book. It was then, he said, that he learned of Trump’s “short attention span” – one trait, Schwartz said, makes Trump incapable of being a good president.

“He was unable to do interviews with me past 10 or 15 minutes. Finally, I had to sit in his office and pick up a phone eight feet away from his desk to listen in on his calls so I could turn this into a book,” Schwartz told GMA.

“The idea that we’d have somebody with a tiny attention span – my 2-year-old grandson has a longer attention span than Donald Trump – is itself terrifying.”