While writing his new novel, CNN anchor Jake Tapper said he realized something – history tends to repeat itself.

Tapper, who anchors two shows on CNN, discussed his first novel, “The Hellfire Club,” at the Jack Morton Auditorium Wednesday. The book, which will debut at No. 3 on the New York Times Bestseller List May 13, is set in 1954 and focuses on a naive Congressman named Charlie Marder at the height of the Red Scare.

Tapper said the book — although fiction — relied heavily upon historical research, which is documented in 10 to 15 pages of endnotes in the book. He recalled a moment in the book where he mentioned Joseph McCarthy, the former U.S. senator who pushed anti-Communist rhetoric during the Eisenhower administration.

“There’s a section in the book where Charlie, at that same party, runs into Joe McCarthy, who’s drinking scotch and bicarbonate soda and then orders a stick of butter to eat,” he said. “He actually did that, amazingly.”

Tapper said his research led him to realize how similar McCarthy’s political strategy was to President Donald Trump’s, including how the media gave McCarthy a free pass on his baseless accusations until he began harassing journalists.

“One of the other things that came out was how resonant the McCarthy era is today,” he said. “They say history doesn’t repeat itself, but it rhymes. And there’s a lot of rhyming when I was doing the research for this book.”

Tapper said one of the lessons of his novel is to keep moral courage in the face of demagoguery. As an example, Tapper pointed to Robert Taft, a former presidential candidate and conservative senate majority leader who didn’t denounce McCarthy  because he thought he could indulge the “smears and indecency” and still remain “respectable.”

“Now his legacy has been written, and turns out that a lot of his legacy is that he didn’t stand up to McCarthy,” Tapper said. “And that’s just a note for people in this town about standing up for what is right and wrong.”

Tapper said that in his experience, newly-elected Congressmen from all political stripes come to D.C. full of courage and conviction to do the right thing and eventually “sell off bits of their soul until there’s nothing left.”

He said the process of writing and researching for the book did not have an impact on his reporting but did force him to “judge more harshly the people who are enabling and the people who know better.”

“It probably had the most effect about how I think about people in Congress who know better, who do not stand up to this nonsense, who do not stand up to the lies,” he said. “It’s not about the policies, it’s just about the indecency.”