At the heart of the Civil Rights Act of 1964 was the constitutional interpretation of the Thirteenth and Fourteenth Amendments. The primary focus was on the role of states to create discriminatory Jim Crow laws that reinforced white supremacy through their "separate but equal" policies.
The Plessy v. Ferguson (1896) ruling dictated that states had the right to create and implement such policies. This created a social strata that was akin to the white dominance under slavery, which could be argued as a violation of the Thirteenth Amendment. The states were creating laws that relegated African Americans to the status of second-class citizens, a clear violation of the Fourteenth Amendment and its equal protection clause.
Ten years prior to the passage of the Civil Rights Act of 1964, the Supreme Court had ruled that “in the field of public education, the doctrine of 'separate but equal' has no place. Separate educational facilities are inherently unequal.” The court's ruling in Brown v. Board of Education of Topeka (1954) set a precedent of the federal government ruling against discriminatory practices in all circumstances, which paved the way for the passage of the Civil Rights Act of 1964.