Robert Kennedy, Jr. and the Conspiracy Theory Embracers.

Robert F. Kennedy, Jr.’s father might have become president if he hadn’t been assassinated. The younger Kennedy has a respectable track record as an environmental lawyer. For years, I had assumed that he was a progressive, as is traditional in the Kennedy family, and maybe he is, except that something in his psyche caused him to latch on to baseless conspiracy theories that typically attract members of the Trump cult.

Kennedy is challenging Biden, running on an anti-vaccination platform for the Democratic Presidential nomination. He has a sizable following and some very rich and influential backers. The New York Times opinion writer Michelle Goldberg had a terrific article about these people yesterday. They are serious, and many of them are sincere. Conspiracy theories — especially ones relating to vaccinations — are like effects of a virulent pathogen that infects human brains. A sizable percentage of the U.S. population is vulnerable to it for reasons I don’t understand.