Russell Muirhead and Nancy L. Rosenblum are professors of government at, respectively, Dartmouth and Harvard. A few years ago, they found themselves, in their words, “startled into thought.” Yes, they knew, crazy ideas were a fixture of American life. But not this crazy. “The subject required more detailed and thoughtful interpretation,” the two write at the beginning of A Lot of People Are Saying: The New Conspiracism and the Assault on Democracy. Elizabeth Kolbert writes in the New Yorker that among the differences between “classic” conspiracy theories and the new conspiracism is their constituencies. Historically, Muirhead and Rosenblum maintain, it’s been out-of-power groups that have been drawn to tales of secret plots. Today, it’s those in power who insist the game is rigged, and no one more insistently than the so-called leader of the free world.