The Attack That Changed Policy
On December 7, 1941, Japan attacked Pearl Harbor. The strike was meant to weaken American power in the Pacific, but it produced the opposite result: public support for entering World War II surged.
Mobilizing a Nation
The United States redirected its economy toward war. Factories produced ships, aircraft, weapons, food, and fuel at extraordinary rates. Unemployment ended, millions entered higher-productivity jobs, and industries recruited women and Black workers. Although 40 percent of GDP went to the war effort, wartime wages and savings helped lay the foundation for postwar growth.
Global Consequences
American forces stopped Japanese expansion at Midway, fought across the Pacific, and helped defeat Nazi Germany after D-Day. The Manhattan Project produced atomic weapons, used against Hiroshima and Nagasaki in August 1945. The war killed about 400,000 American military personnel and civilians.
Pearl Harbor did more than bring the United States into a war. It transformed the country into a global military, economic, and technological power—and ended the long era of American isolationism.