Until the mid-twentieth century, Plessy v. Ferguson gave a "constitutional nod" to racial segregation in public places, foreclosing legal challenges against increasingly-segregated institutions throughout the South. The railcars in Plessy notwithstanding, the black facilities in these institutions were decidedly inferior to white ones, creating a kind of racial caste society. However, in the landmark decision Brown v. Board of Education (1954), the "separate but equal" doctrine was abruptly overturned when a unanimous Supreme Court ruled that segregating children by race in public schools was "inherently unequal" and violated the Fourteenth Amendment. Brown provided a major catalyst for the civil rights movement (1955-68), which won social, not just political and civil, racial equality before the law. After four decades, Justice Harlan's dissent became the law of the land. Following Brown, the Supreme Court has consistently ruled racial segregation in public settings to be unconstitutional.
Plessy v. Ferguson, 163 U.S. 537 (1896), was a landmark United States Supreme Court decision upholding the constitutionality of state laws requiring racial segregation in public facilities under the doctrine of "separate but equal".