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.
Pacific War
In the early hours of 7 December (Hawaiian time), Japan launched a major surprise carrier-based air strike on Pearl Harbor without explicit warning, which crippled the US Pacific Fleet, leaving eight American battleships out of action, 188 American aircraft destroyed, and 2,403 Americans dead. At the time of the attack, the US was not officially at war anywhere in the world as the Japanese embassy failed to decipher and deliver the Japanese ultimatum to the American government before noon December 7 (Washington time), which means that the people killed or property destroyed at Pearl Harbor by the Japanese attack had a non-combatant status. The Japanese had gambled that the United States, when faced with such a sudden and massive blow, would agree to a negotiated settlement and allow Japan free rein in Asia. This gamble did not pay off. American losses were less serious than initially thought: the American aircraft carriers, which would prove to be more important than battleships, were at sea, and vital naval infrastructure (fuel oil tanks, shipyard facilities, and a power station), submarine base, and signals intelligence units were unscathed. Japan's fallback strategy, relying on a war of attrition to make the US come to terms, was beyond the IJN's capabilities.