Which U.S. Supreme Court case established the principle of "separate but equal"?

The principle of "separate but equal" was established by the Supreme Court case Plessy v. Ferguson in 1896. In this landmark ruling, the Court upheld the constitutionality of racial segregation under the premise that as long as separate facilities were equal, segregation did not violate the Equal Protection Clause of the Fourteenth Amendment. This decision legitimized the practice of racial discrimination and provided a legal foundation for segregation in public facilities, schools, and transportation.

The doctrine remained in effect until it was challenged and overturned by subsequent cases, notably Brown v. Board of Education in 1954, which declared that separate educational facilities are inherently unequal.