Plessy v. Ferguson, legal case in which the U.S. Supreme Court, on May 18, 1896, by a seven-to-one majority (one justice did not participate), advanced the controversial “separate but equal” doctrine for assessing the constitutionality of racial segregation laws. Plessy v. Ferguson was the first major inquiry into the meaning of the Fourteenth Amendment’s (1868) equal-protection clause, which prohibits the states from denying “equal protection of the laws” to any person within their jurisdictions
