what general principle was established with the Plessy V. Ferguson Supreme Court decision?

The general principle established with the Plessy v. Ferguson Supreme Court decision is the doctrine of "separate but equal," which allowed for segregation of public facilities based on race as long as the separate facilities were deemed to be equal in quality. This decision ultimately upheld racial segregation in the United States for several decades until it was eventually overturned by the landmark Brown v. Board of Education decision in 1954.