The Clinton campaign in 2016, for instance, never saw the Bernie Sanders campaign as being driven by millions of people who over the course of decades had become dissatisfied with the party. They instead saw one cheap stunt pulled by an illegitimate back-bencher, foolishness that would be ended if Sanders himself could somehow be removed.

“Bill and Hillary had wanted to put [Sanders] down like a junkyard dog early on,” Allen and Parnes wrote. The only reason they didn’t, they explained, was an irritating chance problem: Sanders “was liked,” which meant going negative would backfire.