The primary argument in The Color of Law is that de jure segregation—segregation implemented by government policy or law—is more significant than de facto segregation, which results from private activity or individual choices. De facto segregation does not have the sanction of the law, while de jure segregation uses the law to mandate the separation of races. It has origins in slave codes before the Civil War and Jim Crow laws following Reconstruction. In the 1896 US Supreme Court Ruling Plessy v. Ferguson, the court upheld the constitutionality of segregation, mandating that “separate but equal” facilities such as schools be provided. This was rarely implemented, and African American neighborhoods were chronically underfunded. The 1917 Supreme Court ruling Buchanan v. Warley declared residential segregation ordinances unconstitutional. However, it wasn’t until the 1948 ruling on Shelley v. Kraemer that the Supreme Court ruled restrictive covenants, which prevented African Americans from moving into White neighborhoods, were unenforceable in a court of law. De jure segregation was officially banned by the Civil Rights Act of 1964, the Voting Rights Act of 1965, and the Fair Housing Act of 1968.