1) Several authoritarian leaders rose to power in the 1930s in Germany, Italy, Japan, and the Soviet Union, appealing to nationalism during a time of economic struggles after World War 1. 2) As fascism and militarism spread in Europe and Asia, the United States initially pursued neutrality through acts of Congress but gradually provided more assistance to Britain through supplies and military aid. 3) Japan's attack on the US naval base at Pearl Harbor in 1941 prompted America to enter World War 2 against Germany and Japan. The country abandoned its former policy of isolationism and neutrality.