The Road To Pearl Harbor, 1919-1941 Season 1 Episode 13 The Phony War:

Hitler' assumption that England would not go to war to defend Poland triggers World War II. The Nazis sweep over Europe and launch their air attack on Britain. American public opinion waivers between desire to help Britain and fight or to maintain neutrality. The 1930's ended with America still unconvinced that its destiny was intertwined with the rest of the world.