On this day in 1941, the Imperial Japanese Navy attacked the US Navy’s Pacific Fleet at Pearl Harbour, Hawaii. The attack – comprised of aerial bombardments on ships at port and the surrounding Army and Marines bases, as well concurrent attacks on US positions elsewhere in the Pacific – was intended as a preemptive strike to knock out the United States’ naval capabilities in the region. The “surprise” nature of the attack shocked and horrified Americans; the following day, US President Franklin Delano Roosevelt declared war on Japan and subsequently brought the country into WWII. To him, December 7th was “a day that will live in infamy”.
Since the 1931 Japanese Invasion of Manchuria, tensions had been steadily rising in the Pacific. As Japanese troops began expanding their empire in Southeast Asia, the US responded by bulking up its military presence in the Philippines and elsewhere. Japanese threats towards the oil-rich Dutch East Indies and Nationalist China – which was supported by the US – caused further American frustration. Heavy sanctions followed, and the Japanese-American relationship went further south. The Japanese saw a preemptive strike as the only option; their oil reserves were rapidly being wrung dry, and the US Pacific Fleet was making their expansion plans difficult. Both sides pretended to discuss a treaty and exchanged diplomatic communications on November 26th; but by then, it was too late, for the Japanese attacking force was already on its way to Hawaii.
The Japanese plan required a total knockout of American power at Pearl Harbour. But during the battle – in which Japanese planes strafed and bombed US ships and personnel – Japanese command recalled some of their forces. The battle was a brutal blow to the Pacific Fleet, but it wasn’t enough to put the fleet out of action. The Americans had been bloodied, and wanted revenge. The ensuing Pacific Campaign of WWII was incredibly bloody, and resulted in the total defeat (through conventional and nuclear means) of the Japanese Empire. Pearl Harbour also brought with it a declaration of war from Nazy Germany; the American entry into the European theatre of operations proved incredibly significant, if not decisive.