Communist study group

According to the Humphrey Bogart biography "Tough Without a Gun," there was an investigation of Communist infiltrations of Hollywood in the 1930s conducted by a senator Martin Dies. One of the actors who came under suspicion was Humphrey Bogart, who was accused of being a member of a "subversive academy" and of attending a "secret meeting at the Malibu home of Paramount production chief B.P. Schulberg. There, he and others had studied the doctrines of Karl Marx."

Sounds a lot like the Communist "study group" which Baird Whitlock wakes up to in HAIL CAESAR! I'll bet the Coens used this incident as their inspiration.