What legal principle was established in the case of Plessy v. Ferguson?

The legal principle established in Plessy v. Ferguson is often summarized by the phrase "separate but equal." This landmark case, decided in 1896, upheld the constitutionality of racial segregation under the doctrine that the segregated facilities for black and white individuals were permissible as long as they were deemed equal. The case arose when Homer Plessy, who was of mixed race, refused to sit in the "colored" section of a railroad car in Louisiana, challenging the state's segregation laws.

The Supreme Court's ruling affirmed that segregation did not in itself constitute unlawful discrimination, thereby legitimizing state-sponsored segregation and reinforcing the notion of racial separation across various public facilities. This decision had profound and lasting implications, essentially codifying laws that sanctioned segregation in many aspects of public life, which would not be fundamentally challenged until the civil rights movement in the 1950s and 1960s. The doctrine of "separate but equal" was later overturned by Brown v. Board of Education in 1954, which found that separate educational facilities were inherently unequal and thus unconstitutional.