Southern states adopted policies of legal racial discrimination following Reconstruction, restricting African American civil rights through measures like literacy tests for voting and poll taxes. These policies were reinforced by Jim Crow laws in the late 1800s that mandated racial segregation in public facilities. The Supreme Court failed to overturn these discriminatory voting laws and ultimately ruled in Plessy v. Ferguson in 1896 that state-mandated segregation was constitutional, legalizing the separate but equal doctrine that justified ongoing racial discrimination.