By the time that the United States entered World War II in December of 1941, Americans had no question about who to blame for it. World War II had been caused by Adolf Hitler's Nazi Germany and Emperor Hirohito's Japan, with Mussolini's Italy aiding and abetting the campaign against freedom. However, these opinions weren't always as firmly held. When the war first began in 1939, not all Americans agreed on where to lay the blame.
