The U.S. Supreme Court decision that established the doctrine of “separate but equal” was Plessy v. Ferguson in 1896. This landmark ruling upheld state laws requiring racial segregation in public facilities, asserting that the separation of races was constitutional as long as the facilities were equal. The decision legitimized a system of racial discrimination that persisted for decades, leading to extensive Jim Crow laws in the South. Despite being intended to ensure equality, the reality was that facilities for African Americans were often inferior. This decision was eventually overturned by Brown v. Board of Education in 1954, marking a critical turning point in the civil rights movement.