During Bill Ayers’s pre-debate book talk at one of D.C.’s chain of progressive salons Busboys and Poets, I briefly feared for my life. The unrepentant terrorist seemed to look right at me—a cardigan-clad reactionary in the third row—when he said, “I get bothered by a lot of right wing trolls who follow me around in different venues and places.”

It turned out this was just his lead-in to a story about a piece of mail he’d received, a bumper sticker: “Bill Ayers And His Wife Should Be In Jail,” it read. Well…