Which Supreme Court case legalized segregation as long as facilities were equal?

The case that legalized segregation as long as facilities were equal is Plessy v. Ferguson. In this landmark 1896 decision, the Supreme Court upheld the constitutionality of racial segregation laws for public facilities under the doctrine of "separate but equal." The ruling paved the way for racial segregation in various aspects of daily life, particularly in the southern United States, by affirming that segregated public spaces did not necessarily violate the Equal Protection Clause of the Fourteenth Amendment, provided that the segregated facilities were of comparable quality.

This case became a cornerstone for subsequent civil rights challenges and was eventually overturned by Brown v. Board of Education in 1954, which ruled that separate educational facilities were inherently unequal and thus unconstitutional. The legacy of Plessy v. Ferguson persisted for many decades, shaping the legal and cultural landscape around segregation and civil rights in America.