World War II invigorated the civil rights movement, galvanizing blacks who during the Great Depression had developed a greater awareness of their potential political influence. During the 1930s many blacks had switched their political affiliation from the Republican Party, "the party of Lincoln" that had freed the slaves, to the Democratic Party, and in 1936 had voted for Franklin Delano Roosevelt to show support for his New Deal programs. The outbreak of war in Europe in 1939 stimulated American industry and the demand for labor. As was the case with World War I, African Americans moved to industrial cities for employment but confronted discrimination in hiring and wages. A. Philip Randolph, president of the Brotherhood of Sleeping Car Porters, informed Roosevelt that 100,000 blacks would march in Washington, D.C., to protest discrimination in defense industries. In June 1941, Roosevelt averted the protest by signing Executive Order 8802, outlawing prejudicial treatment of workers in defense industries and the federal government on the basis of race. Blacks also encountered opportunity along with racism in the armed forces. One million African American men and women served in the military, in segregated units. Blacks in the military and in civilian wartime jobs saw themselves as waging a "double victory" campaign to secure democracy abroad and for themselves in their own country. They emerged from the war with a renewed sense of the rights to equality and freedom in the land that claimed to represent these among the world's nations. During the war, membership in the NAACP swelled tenfold to 500,000.
Numerous factors energized the civil rights movement after World War II. In July 1948, President Harry Truman signed Executive Order 9980, barring racial discrimination in the civil service, and Executive Order 9981, mandating "equality of treatment and opportunity for all persons in the armed forces." The postwar economic boom improved job opportunities for blacks, and higher incomes resulted in rising college enrollments for African Americans and increasing donations to civil rights organizations such as the NAACP. The mass media, including fledgling television, publicized civil rights activism. Furthermore, television broadcasts displayed the material prosperity enjoyed by middle-class whites, feeding African Americans' desires for a better standard of living.