The two world wars were watershed moments for African American life. Black soldiers served in large numbers, volunteering for services in both wars. However, they served in segregated units and struggled to receive officer's commissions.
In both instances, civil rights leaders saw African American involvement in the war effort as an opportunity to assert their rights at home. W. E. B. DuBois, for example, reluctantly supported American involvement in the war for exactly that reason. During World War II, an African American-owned newspaper in Pittsburgh proclaimed a "Double-V" campaign, asserting the need for victory over fascism abroad and racism at home.
In both wars, African American men and women flocked to cities, taking jobs in various lucrative wartime industries. This led to considerable social turmoil, as white workers in southern cities often refused to work alongside African American men. For this reason, both wars witnessed large migrations of black workers, who moved to Northern cities to fill jobs and to escape Jim Crow. In many cases, they faced racism away from the South.
Black soldiers also experienced discrimination in the military and especially towns surrounding military bases around the country. For these reasons, historians identify the Second World War in particular as the wellspring of the movement for civil rights in the United States. Outraged by continued discrimination and sensing that the time was opportune, civil rights leaders like A. Philip Randolph, who threatened a mass strike and march on Washington if black workers were excluded from government jobs, began to organize and push for equality.