Hunter Biden Blames Cancer for Joe Biden’s Disastrous Debate

Hunter Biden said on a podcast episode published this week that he believed his father, former President Joseph R. Biden Jr., was unknowingly suffering from cancer during the disastrous debate performance that led to the end of his 2024 presidential campaign.

“He looked blank,” Hunter Biden said on the “Macrodosing” podcast. “And what do I attribute that to? Well, I now know what to attribute it to.” He added: “My dad had cancer. My dad, he was, and he didn’t know. I mean, we didn’t find out until nine months later that he not only had Stage 4 prostate cancer, but he had Stage 4 metastatic bone cancer, which means that it had been metastasizing for over a three-year period of time.”

Mr. Biden, 83, was diagnosed in May 2025 with an aggressive form of prostate cancer, which had spread to his bones, his office revealed at the time. Last year he also had surgery to remove skin cancer lesions and completed a course of radiation therapy, his office has said.

The June 2024 debate effectively ended Mr. Biden’s re-election bid. During the debate, he lost his train of thought and made confusing comments. He spent the next few weeks trying to reassure allies he could continue his run. But polls, which had already shown voters believed he was too old to be president, turned sharply against him while a cascade of Democrats called for him to drop out of the race. He bowed out in late July 2024.

Vice President Kamala Harris was soon picked by delegates to the Democratic National Convention to replace Mr. Biden. She went on to lose the general election to Donald J. Trump.

Medical experts who were not involved in Mr. Biden’s care say prostate cancer is typically a slow-growing disease that can be present for years before causing symptoms or being diagnosed. They said it was unlikely, though, that Mr. Biden’s debate performance was affected by the cancer that was diagnosed months later.

“This is a disease of older guys, and cognitive decline is associated with advanced age,” said Dr. Paul Monk, a medical oncologist specializing in genitourinary cancers at the Ohio State University Comprehensive Cancer Center. “This is a classic example of association, not necessarily causation.”

Dr. Monk said it is common for advanced prostate cancer to spread to the bones, as Mr. Biden’s did, but quite rare for it to spread to the brain and thereby cause cognitive issues.

Dr. Paul Nguyen of Mass General Brigham Cancer Institute also said it was “extremely unlikely” that prostate cancer was the cause of his poor debate performance. “Prostate cancer does not metastasize to the brain, generally,” he said.

Hunter Biden’s remarks about his father’s debate performance came amid his tour of the American podcast landscape. In recent weeks he sat for lengthy interviews with Gov. Gavin Newsom of California, the right-wing conspiracy theorist Candace Owens and a show called “Friends Keep Secrets,” in which he discussed his art and recovery from drug addiction.

Former President Biden has appeared at a handful of recent political events and is often seen in Delaware and riding the Amtrak back and forth to Washington. He has written a memoir, which is due for release in November, two weeks after the midterm elections.

Hunter Biden’s comments are the latest of at least a half-dozen different public explanations of Mr. Biden’s struggles in the debate.

Immediately after the debate, the president himself blamed a “bad cold” for his performance. He also has claimed to have been distracted and suggested “it’s hard to debate a liar.”

A week later he told donors at a Virginia fund-raiser that he had traveled too much before the debate. “I didn’t listen to my staff,” he said then, saying he “nearly fell asleep onstage.”

Last summer, Hunter Biden claimed his father had been given the prescription sleep aid Ambien to help recover from two trans-Atlantic flights and a star-studded fund-raiser in Los Angeles in the preceding weeks. (Hunter Biden later clarified to ABC News that he did not know for sure whether his father took Ambien before the debate.)

When Jill Biden, the former first lady, was on her book tour this spring, she said during an interview with CBS News that she thought while watching her husband that he was “having a stroke.” She added: “I had never, ever seen Joe like that. Before or since.”

T.J. Ducklo, a spokesman for the former president, did not respond to messages on Friday.

Hunter Biden, during a brief phone interview on Friday, declined to elaborate on his new assertion about his father’s health during the debate.

“I’m not going to comment,” he said. “I said what I said.”