Guinn v. United States: Supreme Court Strikes Down Grandfather Clauses as Fifteenth Amendment Violation

The Supreme Court unanimously struck down Oklahoma’s grandfather clause in Guinn v. United States, marking the first time the Court invalidated a state voting restriction as a Fifteenth Amendment violation since Reconstruction. Chief Justice Edward White, himself a former Confederate soldier and Louisiana segregationist, wrote that Oklahoma’s transparent attempt to exempt whites from literacy tests while disenfranchising Black voters violated the constitutional prohibition on racial discrimination in voting.

Oklahoma’s 1910 constitution required voters to pass a literacy test unless they or their ancestors had been entitled to vote on January 1, 1866—a date carefully chosen because no Black Americans could vote anywhere in the country before the Fifteenth Amendment’s 1870 ratification. The grandfather clause thus exempted illiterate whites while subjecting Black citizens to tests administered with discriminatory intent by hostile registrars.

The NAACP, founded just six years earlier, celebrated the ruling as a major victory in its legal campaign against Jim Crow. However, the decision’s practical impact proved limited. Oklahoma immediately enacted a new law giving voters who had voted in 1914 (when the grandfather clause was still in effect) permanent voter status, while requiring all others—almost entirely Black citizens—to register within an eleven-day window or be permanently disenfranchised. This replacement scheme would not be struck down until 1939.

Other Southern states simply intensified alternative disenfranchisement mechanisms: literacy tests with subjective administration, poll taxes, white primaries, voucher requirements, and understanding clauses. Mississippi’s registrars asked Black applicants to interpret obscure constitutional provisions while accepting any answer from whites. The ruling demonstrated both the potential and the limits of judicial enforcement—states could evade narrow constitutional rulings through innovative discrimination.

The decision illustrated a recurring pattern: formal constitutional victories that changed little in practice without sustained federal enforcement. Black voter registration in the South remained below 5% for decades after Guinn. The grandfather clause’s demise simply shifted suppression to other mechanisms until the Voting Rights Act of 1965 finally addressed the full architecture of disenfranchisement.