The radical left and the liberal left are deeply divided. There have been watershed years on the left before, in which radicals betrayed their liberal allies in colleges, unions, and political parties, seeking to destroy their competitors for power. These periods sent many liberals, shocked by the ferocity of their former friends, traveling toward conservatism. 1968 was such a year, when social science liberals like Norman Podhoretz and Midge Decter got fed up with the cynicism of counterculture radicals. The years 1936–39, between Stalin’s purge and his pact with Hitler, were a similar time when the ruthlessness and deceit of the radical left were on full display. A long list of intellectuals realized that communism was a defining evil of the age and resolved to fight it. Fellow travelers like Lionel Trilling and former communists like James Burnham and Whittaker Chambers were only a few. This fracture is happening again over the progressive agenda and its totalitarian ambitions, and I’ve been following the story. Yesterday’s article by Michael Powell about the civil war in the ACLU over the first amendment shows how traumatic this fracture has become.