The phrase "separate but equal" is the trademark expression originated in the Plessy v. Ferguson Supreme Court Case. This case had the potential to move toward more equality for black and white people in the United States, however, the ruling upheld the Jim Crow Laws and actually worsened the discrimination against African-Americans.
Here's what happened, Homer Plessy was a mixed race civil rights activist in the 1890's. He purchased a first class ticket and boarded the East Louisiana Railroad where he sat in the train car marked "whites only." When the conductor approached him to move to the cars for black people, Homer said that he is only 1/8th black. However, at this time the "one drop rule" was in full effect, this meant that if you had one drop of African-American blood or 100% African-American, you were treated the same and forced to abide by The Jim Crow Laws. Plessy was then kicked off the train, put in jail over night and released on a $500 bond.
Homer went on to argue that his 13th and 14th Amendment Rights were violated. The 13th amendment made slavery illegal and the 14th amendment said that any person born in the United States was considered an American citizen (these laws freed all the slaves and gave them citizenship at the end of the Civil War.) However, his case lost before Judge John Ferguson and continued on to the US Supreme Court where the Jim Crow Laws were cited and "separate but equal" was reconfirmed as the law of the land.
