There were two writer's unions in those days[ during World War II ] , the studio-friendly guild called the Screen Playwrights, and the more activist Writer's Guild. The studios were fairly upset that their group wasn't effective, and they sought to punish the other union by labeling them as Communists.
Jay RoachWhen Dalton Trumbo and his friends joined the Communist Party it was 1943, and Russia was our ally in World War II. This was connected to a very popular movement of artists and intellectuals at that time towards anti fascism, and an alliance with the union movement.
Jay RoachHedda Hopper was a better direct opponent to [Dalton] Trumbo. We wanted to use Trumbo's battles to represent the larger battles, so the audience could understand the personal sacrifice he went through and the personal damage to his family. The choices were about who were the best representations of his antagonists, which is why we chose as we did.
Jay Roach