It seems that you have missed the necessary options for us to answer this question, but I hope this answer helps. Anyway, during the first years of World War II, the U.S. government changed its foreign policy and in September 1939, President Roosevelt declared his commitment to U.S. neutrality. But by September 1940, he supported "all aid (to Allies) short of war", and the one that caused this change is this: The Axis seemed to be winning the war. Hope this helps.