Tucker Carlson, the former Fox News star turned podcaster, has come under fire for hosting a Holocaust revisionist on his show, who posited that it was Winston Churchill, not Adolf Hitler, who was the “chief villain” of World War II — drawing a rebuke from conservative lawmakers as well as the White House.

The comments were made by the podcaster Darryl Cooper on Mr. Carlson’s show “Tucker on X” on the social media platform. Mr. Carlson, who has hosted the show since Fox severed ties with him in 2023, introduced Mr. Cooper as “the most important popular historian working in the United States today.”

Mr. Cooper, who has a podcast and newsletter called “Martyr Made,” proceeded to make a variety of false claims about the Holocaust and World War II, including that millions of people in concentration camps “ended up dead” merely because the Nazis did not have enough resources to care for them, rather than as a result of the intentional genocide that it was. Mr. Cooper also claimed that Mr. Churchill, the British prime minister at the time, was “primarily responsible for that war becoming what it did,.”

As of Friday morning, the video had been viewed nearly 30 million times. Elon Musk, the billionaire owner of X, on Tuesday promoted Mr. Carlson’s interview as “very interesting” and “worth watching,” but later deleted his post.

Mr. Carlson’s endorsement of Mr. Cooper has sparked considerable outrage from the Biden administration and among some conservatives.

Representative Mike Lawler, Republican of New York, condemned the interview, saying in a statement to The Jewish Insider: “Platforming known Holocaust revisionists is deeply disturbing.”