In the case Plessy v. Ferguson, what did the Supreme Court upheld?
The Supreme court upheld the principle of separate but equal.
The plaintiff claimed that it was unconstitutional for the railroad to deny him the first class seat in the front of the train that he had paid for because he was African American. The law of Louisiana said that facilities on the train must be separated by race.
The local judge Ferguson found the plaintiff guilty and sentenced him to jail. The plaintiff appealed the the Supreme Court. Sadly the Supreme court at that time ruled in favor of the state of Louisiana that segregation was legal under the constitution.