John H. Ferguson, at the Louisiana Supreme Court, arguing that the segregation law violated the Equal Protection Clause of the Fourteenth Amendment, which forbids states from denying "to any person within their jurisdiction the equal protection of the laws," as well as the Thirteenth Amendment, which banned slavery.

Overview: Louisiana had adopted a law in 1890 that required railroad companies to provide racially segregated accommodations. In 1892, the state of Louisiana prosecuted Homer Plessy, a man who was 7/8 Caucasian and 1/8 Black, for refusing to leave a passenger car designated for whites.

The ruling in this Supreme Court case upheld a Louisiana state law that allowed for "equal but separate accommodations for the white and colored races." During the era of Reconstruction, Black Americans' political rights were affirmed by three constitutional amendments and numerous laws passed by Congress.

In short, segregation did not in itself constitute unlawful discrimination. In dissent, John Marshall Harlan argued that the Constitution was color-blind and that the United States had no class system. Accordingly, all citizens should have equal access to civil rights.