Here are a list of precedents for the case.
Plessy v. Ferguson (1896): The separate but equal doctrine was expoused. Equality of treatment is accorded when the races are provided substantially equal facilities, even though those facilities be separate.
Missouri ex.rel.. Gaines v. Canada (1938): At a graduate school, inequality was found in that specific benefits enjoyed by white students were denied to Negro students of the same educational qualifications.
Strauder v. West Virginia (1879): No State shall deprive any person of life, liberty, or property, without due process of law, or deny to any person within its jurisdiction the equal protection of the laws.