The isolationist approach to foreign policy meant U.S. leadership in world affairs diminished after World War I. Overseas, certain nations saw the growth of tyrannical governments that reasserted their power through aggression and created conditions leading to the Second World War. After Pearl Harbor, the United States entered World War II, which changed the country’s focus from isolationism to international involvement.
1. During the 1930s, the U.S. government attempted to distance the country from earlier interventionist policies in the Western Hemisphere as well as retain an isolationist approach to events in Europe and Asia until the beginning of WWII.
2. The United States mobilization of its economic and military resources during World War II brought significant changes to American society.
3. Use of atomic weapons changed the nature of war, altered the balance of power and began the nuclear age.