WWll

What triggered the U.S.A. to join the war? ​

On December 7, 1941, while Germany was fighting the war in Moscow, Japan suddenly attacked the major U.S.A. naval base, Pearl Harbor. The next day President Roosevelt declared war on Japan, four days after pearl harbor, Germany declared war on the United States. President Roosevelt called on congress for immediate and massiv expansion of the armed forces. On December 11, 1941, the United States of America had entered the World War ll.