Why didn't the U.S. do anything to stop the fascist invasions of Manchuria or Ethiopia, or to stop Germany's reoccupation of the Rhineland?
Answer: Britain, France, and the United States were not willing to risk war for high principle if validating that principle imperiled vital interests. None of the countries had an active interest in whether or not Japan controlled Manchuria. If the United States denied joining the League, nations would have no idea how to object in case Germany walked out. Hitler’s military occupation of the Rhineland was a direct challenge to France. Yet, the USA did not act militarily since France, with its huge army, did not do that in its interests (Buchanan).