The Supreme Court struck down grandfather clauses as a violation of the Fifteenth Amendment.

Grandfather clauses indirectly discriminated against African Americans,African Americans;grandfather clauses[grandfather clauses] usually by waiving the literacy requirement for voting to those whose ancestors had been entitled to vote before the ratification of the Fifteenth Amendment. As late as Giles v. Harris[case]Giles v. Harris[Giles v. Harris] (1903), the Supreme Court had declared it did not have authority to prohibit indirect barriers on voting. In 1908 the Oklahoma state constitution was amended to include a literacy test with a grandfather clause.Grandfather clausesVote, right to;Guinn v. United States[Guinn v. United States]Discrimination, race;Guinn v. United States[Guinn v. United States]Grandfather clauses

By an 8-1 vote, the Supreme Court found that the clause was unconstitutional. Justice Edward D. WhiteWhite, Edward D.;Guinn v. United States[Guinn v. United States] reasoned that the measure was a transparent obstacle that applied to black but not to white voters. The Guinn decision, despite its symbolic importance, had limited practical effect. By 1915 Georgia was the only other state with an unexpired grandfather clause. In addition, White’s opinion explicitly endorsed the continuation of literacy tests, without any specific requirements for fairness in testing.[case]Guinn v. United States[Guinn v. United States]

Fifteenth Amendment

Grandfather clause

Vote, right to

Williams v. Mississippi