Which legal principle was established by Plessy v. Ferguson that supported segregation?

The legal principle established by Plessy v. Ferguson, "Separate but Equal," played a crucial role in legitimizing racial segregation in the United States for many decades. In the 1896 case, the Supreme Court ruled that state laws requiring racial segregation in public facilities were constitutional as long as the separate facilities were equal in quality. This doctrine provided a legal framework that allowed for segregation in public schools, transportation, and other areas, reinforcing racial discrimination under the guise of equality.

The decision effectively upheld laws that segregated African Americans from whites, asserting that race-based separation did not violate the 14th Amendment's Equal Protection Clause, as long as the separate facilities were purportedly equal. This principle was a significant factor in institutionalizing racism and segregation until it was finally overturned in later rulings, most notably by Brown v. Board of Education in 1954, which declared that separate educational facilities are inherently unequal.