World War II impacted the United States in many ways. First, World War II ended the Great Depression, as people either went to work in munitions factories or joined the armed forces. This is important to note because even the New Deal programs could never get unemployment under ten percent. WWII also helped end segregation, as Franklin Roosevelt issued an order stating that any munitions plant that received a government contract had to be desegregated. Women also joined the workforce in droves; while Rosie the Riveter is a popular figure, many women did not do any actual "riveting," but were rather in clerical roles. Still, this was key in that women were becoming primary earners while their husbands served overseas. Soldiers returning home received government aid through the GI Bill, which gave soldiers either a free college education or loans to start businesses. The government did this to avoid another round of the Bonus Marchers it faced during the Great Depression.
Internationally, World War II changed the United States in that it solidified the nation's role as a superpower. The United States had an internationalist leaning after the war, rebuilding Western Europe using the Marshall Plan and leading the creation of the United Nations. This contrasts with the United States' actions after World War I when it did little to rebuild war-torn Europe and insisted on the repayment of all money owed to it by European nations. The United States also had an atomic bomb, which became a leading factor in a growing Cold War with the Soviet Union. American armed forces were also larger than the rest of the world's combined, and this continued to be a trend. The United States also took a leading role in prosecuting war criminals in both Germany and Japan. Additionally, the United States occupied Germany and Japan to rebuild the countries and remove any of the remaining military fanaticism that caused the war. The United States also took key steps in creating Israel and making sure the United States would be Israel's primary supporter.