Before the pact's announcement, Communists in the West denied that such a treaty would be signed. Future member of the Hollywood Ten Herbert Biberman denounced rumors as "Fascist propaganda". Earl Browder, head of the Communist Party USA, stated that "there is as much chance of agreement as of Earl Browder being elected president of the Chamber of Commerce." Beginning in September 1939, the Soviet Comintern suspended all anti-Nazi and anti-fascist propaganda, explaining that the war in Europe was a matter of capitalist states attacking each other for imperialist purposes. Western Communists acted accordingly; while before they supported protecting collective security, now they denounced Britain and France going to war.

Who was part of Hollywood Ten?