Pearl Harbor and America Enters World War II

On December 7, 1941 — "a date which will live in infamy," as President Franklin Roosevelt declared — Japan launched a surprise attack on the U.S. naval base at Pearl Harbor, Hawaii, killing 2,403 Americans and damaging or destroying 19 ships and 328 aircraft. The attack united a deeply divided nation: Congress declared war the next day with only one dissenting vote. American industrial capacity — the "Arsenal of Democracy" — proved decisive. The U.S. produced 300,000 aircraft, 86,000 tanks, and 2 million trucks during the war. American forces fought across the Pacific and, after D-Day (June 6, 1944), across Europe. The war ended with the atomic bombings of Hiroshima and Nagasaki in August 1945 and Japan's surrender. World War II transformed the United States from a reluctant isolationist power into the world's dominant military and economic superpower — a role it has occupied ever since. The war also launched the nuclear age, the United Nations, and the Cold War.