In his 1903 book, The Souls of Black Folk, W. E. B. Dubois asserted, "The problem of the Twentieth Century is the problem of the color-line." He referred to the physical separation of the races that was evident not only in the South where in most places the separation was legally and sometimes brutally enforced, but also of the separation of the races in all intellectual and professional pursuits throughout the nation.
In 1896, the Supreme Court ruled in Plessy v. Ferguson that a state law requiring separate seating for white and black passengers in railway cars was not a deprivation of the equal protection of the laws as required by the Fourteenth Amendment so long as the separate accommodations were substantially equal. The "separate but equal" doctrine permitted state governments to adopt many laws requiring separation of the races, and during the first half of the twentieth century federal and state courts relied on that doctrine to uphold racial segregation and discrimination statutes.
Until the second half of the twentieth century African Americans were relegated to substandard facilities in public places, in transportation, and at all mixed-race events and organizations, including the military. In the South they were excluded from clubs, advanced employment and education, and sports. Underlying the laws requiring physical separation of the races was racial prejudice among white people that was built on and that encouraged discriminatory stereotypes and caricatures.
In Virginia, Walter Ashby Plecker, the head of the state's Bureau of Vital Statistics, employed his position to wage a campaign that forced African Americans to register as "colored" and prevent them from passing as white or sending their students to white schools. Plecker also systematically worked to reclassify all Virginia Indians as "Negro" or "colored" and thereby subject them to the same discriminatory laws that kept them from marrying white people or sending their children to schools intended for white students.