Chief Justice White strikes down Oklahoma's grandfather clause; court rules it guts the Fifteenth Amendment

Oklahoma joined the Union in 1907 with voting open to men of all races, but by 1910 the state had passed a constitutional amendment pairing literacy tests with a grandfather clause that exempted any man whose ancestors could vote before 1866 — which is to say, almost every white voter and almost no Black one. On June 21, 1915, Chief Justice Edward Douglass White delivered a unanimous Supreme Court opinion in Guinn v. United States, ruling the clause a direct violation of the Fifteenth Amendment. Oklahoma and other Southern states moved quickly to replace it with poll taxes and other mechanisms, but the ruling established, for the first time, that courts would strike down facially neutral laws designed to circumvent the Amendment's guarantee…