The Voting Rights Act was in place as the centerpiece of the protection of African American voting rights, but much remained to be done to ensure that right would be respected as a lasting guarantee. The Supreme Court played a major role in eradicating racial restrictions on the franchise as well. The Court had all but ignored the 15th Amendment for generations, upholding the constitutionality of any law that did not overtly violate its prohibition on racial discrimination. But the Warren Court reversed course in the 1960s defending the guarantees of the 15th Amendment, and even finding 14th Amendment equal protection grounds for striking down discriminatory legislation.
Six states—Alabama, Georgia, Louisiana, Mississippi, South Carolina, and Virginia—challenged the constitutionality of the Voting Rights Act, claiming its core provisions “exceed the powers of Congress and encroach on an area reserved to the states by the Constitution.” The Court upheld the law—and the federal takeover of state voting laws it represented—in the 1966 case South Carolina v. Katzenbach. The decision found the provisions of the Voting Rights Act to be “a valid means for carrying out the commands the 15th Amendment.” Chief Justice Earl Warren, writing the opinion for the Court, called attention to “the blight of racial discrimination in voting, which has infected the electoral process… for nearly a century” in the United States, as well as the failure of less drastic measures to “cure the problem of voting discrimination.” The 8-1 decision validated the “array of potent weapons” for enforcing the 15th Amendment included in the Voting Rights Act, and expressed the hope that “millions of non-white Americans will now be able to participate for the first time on an equal basis in the government under which they live.”
The Voting Rights Act and the decision in South Carolina v. Katzenbach established firmly two major changes to voting law in the United States. Racial barriers to voting, overt or disguised, were now illegal. Not only that, but Congress was empowered to take extraordinary measures to dismantle these racial barriers. After lying dormant for almost a century, the 15th Amendment was finally being enforced. Chief Justice Earl Warren concluded his opinion in South Carolina v. Katzenbach with the words: “we may finally look forward,” he wrote, “to the day when truly ‘the rights of citizens of United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude.’”
And on a much broader level, the foundation of American suffrage had shifted: defined for almost 200 years by states, the federal government had taken over as the primary force shaping the franchise in the United States.