Third and fourth terms of the presidency of Franklin D. Roosevelt
On the morning of December 7, 1941, the Japanese struck the U.S. naval base at Pearl Harbor with a surprise attack, knocking out the main American battleship fleet and killing 2,403 American servicemen and civilians. The great majority of scholars have rejected the conspiracy thesis that Roosevelt, or any other high government officials, knew in advance about the Japanese attack on Pearl Harbor. The Japanese had kept their secrets closely guarded, and while senior American officials were aware that war was imminent, they did not expect an attack on Pearl Harbor. Roosevelt had anticipated that the first attack would take place in the Dutch East Indies, Thailand, or the Philippines.
Empire of Japan
Facing an oil embargo by the United States as well as dwindling domestic reserves, the Japanese government decided to execute a plan developed by Isoroku Yamamoto to attack the United States Pacific Fleet in Hawaii. The Imperial Japanese Navy made its surprise attack on Pearl Harbor, Oahu, Hawaii, on Sunday morning, December 7, 1941. American forces sustained significant losses. The primary objective of the attack was to incapacitate the United States long enough for Japan to establish its long-planned Southeast Asian empire and defensible buffer zones. The American public saw the attack as a treacherous act and rallied against the Japanese. Four days later, Adolf Hitler of Germany, and Benito Mussolini of Italy declared war on the United States, merging the separate conflicts. The United States entered the European Theatre and Pacific Theater in full force, thereby bringing the United States to World War II on the side of the Allies.