Which event prompted the U.S.A. to enter into World War II?

The headlines of major papers announced that the U.S. suffered an aerial attack at Pearl Harbor on December 7, 1941. The following day, President Franklin D. Roosevelt asked Congress to declare war. After this happened, on December 11, 1941, Germany and Italy, who were allies to Japan, also declared war upon the United States.

Japan's attack upon the American forces in the Pacific were made in order to cripple the naval forces so that Japan...

The headlines of major papers announced that the U.S. suffered an aerial attack at Pearl Harbor on December 7, 1941. The following day, President Franklin D. Roosevelt asked Congress to declare war. After this happened, on December 11, 1941, Germany and Italy, who were allies to Japan, also declared war upon the United States.

Japan's attack upon the American forces in the Pacific were made in order to cripple the naval forces so that Japan could control that area. However, the U.S. recovered from its losses and struck back in a devastating bombing mission over Tokyo, named the Doolittle Raid. This mission was clearly a retaliation against the bombing in Hawaii, and it helped to restore the morale of the Armed Services.

Also, in June of that year, the United States Navy defeated Japanese forces in the Battle of the Midway. Furthermore, in 1945, the U.S.captured the islands of Iwo Jima and Okinawa that lie near Japan. These victories, along with the bombing of the cities of Hiroshima and Nagasaki, effected the end of the Pacific War in August of 1945.