“The Sociopath,” Schwartz told the New Yorker in a recent interview.

Schwartz, who was a lauded journalist when Trump tapped him to write the Art of the Deal in the late ’80s, says he’s remorseful about having written the book. “I put lipstick on a pig,” he said. “I feel a deep sense of remorse that I contributed to presenting Trump in a way that brought him wider attention and made him more appealing than he is.”

The writer said he hadn’t spoken publicly about Trump until the 2015 launch of the business mogul and reality TV star’s presidential campaign. When the mogul listed Deal as one of his qualifying accomplishments he fired off a pithy tweet: “Many thanks Donald Trump for suggesting I run for President, based on the fact that I wrote ‘The Art of the Deal,’ ” he said at the time.

In the New Yorker interview, Schwartz suggested a Trump presidency might not end well for the world. “I genuinely believe that if Trump wins and gets the nuclear codes there is an excellent possibility it will lead to the end of civilization,” he said.

Read the entire interview at the New Yorker.

This article originally appeared on Time.com.