What principle was upheld by Plessy v. Ferguson?

Plessy v. Ferguson is historically significant for establishing the legal doctrine of "separate but equal." This principle allowed for racial segregation in public facilities as long as the separate facilities for the different races were considered equal in quality. The case arose when Homer Plessy, who was of mixed race, was arrested for sitting in a "whites-only" car on a Louisiana train. The Supreme Court's decision upheld the constitutionality of state laws requiring racial segregation, asserting that segregation did not violate the Equal Protection Clause of the Fourteenth Amendment, provided that the segregated facilities were equal. This ruling legitimized racial discrimination and segregation in the United States, impacting civil rights for decades until it was overturned by later legislation and court decisions.

This outcome is pivotal in understanding the historical context of civil rights in the U.S., as it laid the groundwork for further legal challenges against segregation and discrimination.