Pearl Harbor and the American Entry into the War

On December 7, 1941, Japanese planes engaged in a surprise attack on the U.S. naval base at Pearl Harbor in Hawaii. The Americans were caught unprepared, and suffered considerable casualties and loss of ships and airplanes. More than 2,000 American sailors and soldiers were killed. The Japanese also launched attacks in the Philippines and other nations in East Asia. The following day, President Franklin D. Roosevelt addressed the U.S. Congress, and denounced the attack as deed that would "live in infamy" and asked Congress to declare war on Japan. Congress declared war on Japan. Three days later, Germany and Italy declared war on the U.S., which in turn declared war on those nations.

After the U.S. declared war on Japan, President Roosevelt in February 1942 issued Executive Order 9066, which required that Japanese-Americans living on the West Coast be interned in so-called Relocation Centers for the duration of the war. More than 100,000 Japanese-Americans, most of whom were American citizens, were forced to leave behind their homes, farms, and businesses and spend the war years under guard in these camps. They protested that they were loyal Americans, and that their rights were being unfairly violated. The U.S. government did not subject Americans of German or Italian ancestry to similar treatment. In the the case of Korematsu v. U.S. (1944), U.S. Supreme Court declared that internment was justifiable during a wartime emergency. Despite discrimination by the U.S. Government, many Japanese-Americans served in the war, and a Japanese-American regiment, the 442nd Infantry, even became the most decorated American combat unit of the entire war.

The United States mobilized for World War II, raising a large army and navy (more than 15 million Americans served in the war), and producing vast numbers of aircraft, weapons, and other supplies. World War II pulled the U.S. out of the Great Depression, which began with the stock market crash in 1929. Wartime spending created thousands of jobs, ending years of unemployment. American industrial capacity proved indispensable to the Allies' victory.

For women and black Americans, wartime production provided new opportunities. With millions of men serving in the military, women took factory jobs from which they had previously been excluded. The image of Rosie the Riveter became widely recognized thanks to posters saluting women's contribution to the war effort.

Black Americans also benefited during wartime, gaining access to industrial jobs. Many black Americans subscribed to the Double-V Strategy, which sought victory over fascism abroad and racial discrimination at home. Black Americans hoped that their service to the nation, both in wartime industries and in the military, would reduce the discrimination they endured in the U.S. A. Philip Randolph, leader of the Union of Sleeping Car Porters and Maids, a railway union with many black members, insisted to President Roosevelt that black Americans be treated equally in wartime work, and promised to stage a massive protest in Washington, DC, if necessary, to achieve his goal. Roosevelt issued Executive Order 8802, which guaranteed black Americans equal access and equal pay in war-related industries, and established the Fair Employment Practices Commission to investigate accusations of discrimination. Although the American military remained segregated during the war, with black and white soldiers and sailors generally assigned to separate units, the number of black men enlisted in the military grew steadily, and many black men served in combat by the war's end.

In the United States, World War II greatly expanded the size and budget of the U.S. Government Expanded opportunities for black Americans contributed to the growth of the Civil Rights movement. The GI Bill (or Servicemen's Readjustment Act, passed in 1944), which enabled many veterans to gain an education or purchase a house, greatly aided American prosperity in the 1950s and 1960s.