Final answer:
Notable figures like Booker T. Washington and oppressive legal systems such as Jim Crow laws and South African apartheid have advocated for the separation of races, which was legally upheld by the U.S. Supreme Court's doctrine of 'separate but equal'. However, others like Frederick Douglass opposed segregation and worked towards racial integration.
Step-by-step explanation:
Throughout history, several notable figures and legal systems have advocated for the separation of the races. Booker T. Washington's 1895 address at the Atlanta Cotton States and International Exposition suggested a form of separation in social aspects while advocating for unity in mutual progress. His stance was criticized by W.E.B. Du Bois and other African-American intellectuals. In a different context, the notorious Jim Crow laws implemented across many states, particularly in the South, mandated the segregation of African Americans in public and private facilities, leading to vast inequalities. This policy of separation was ultimately backed by the U.S. Supreme Court's ruling in Plessy v. Ferguson (1896), which established the doctrine of 'separate but equal'.
Another form of racial separation emerged internationally with the policy of apartheid, created by the white minority government in South Africa in 1948, mandating racial segregation and severe discrimination against the non-white population.
However, as the twentieth century progressed, figures like Frederick Douglass and others advocated for racial integration and condemned discrimination, setting the stage for the eventual challenges to segregation and the civil rights movements that would follow.