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.
United States Pacific Fleet
Subsequently Pacific Fleet engagements during World War II included the Battle of Guam, the Marshalls-Gilberts raids, the Doolittle Raid, the Solomon Islands campaign, the Battle of the Coral Sea, the Battle of Midway, the Battle of the Eastern Solomons, the Battle of the Santa Cruz Islands, the Battle of the Philippine Sea, the Gilbert and Marshall Islands campaign, the Battle of Leyte Gulf, and the Battle of Okinawa. More minor battles included the Battle of Dutch Harbor. The Submarine Force began a sustained campaign of commerce raiding against Japan's merchant marine, beginning the very first day of the war, which ultimately claimed 1,314 ships totalling about 5.3 million tons (by the imperfect postwar reckoning of the Joint Army-Navy Assessment Committee, JANAC). The West Loch disaster occurred at Pearl Harbor on 21 May 1944.