In November a new movie will be released about the blacklisted Hollywood screenwriter Dalton Trumbo. The author will be played by the “Breaking Bad” star Bryan Cranston, and among his famous co-stars are Helen Mirren, John Goodman, and the comedian Louis C. K.

What probably won’t be presented, even though Trumbo himself acknowledged it, is that he and his Communist Party Screenwriters Guild confederates blacklisted anti-communists before they themselves were blacklisted. In this way they prevented the making of a motion picture of Arthur Koestler’s Darkness at Noon.

Trumbo had also “named names.” Prior to the McCarthy hearings, he had contacted the FBI to inform on all those who wrote to him prot ...