The 15th Amendment, ratified in 1870, banned denying the vote based on race. Southern states responded by inventing ways to disenfranchise Black citizens without mentioning race at all. Mississippi led the way at its 1890 constitutional convention, adopting poll taxes, literacy tests, and residency requirements that other Southern states quickly copied. The results were devastating: Black voter registration in Mississippi plummeted from roughly 90 percent during Reconstruction to below 6 percent by 1892. Literacy tests were especially effective tools of discrimination because white registrars graded them subjectively -- identical answers could be marked correct for white applicants and wrong for Black ones. Grandfather clauses exempted anyone whose ancestor voted before 1867 (when Black men could not yet vote) from the literacy test, protecting illiterate white voters while excluding Black ones. Poll taxes forced poor Black citizens to pay for a right the Constitution guaranteed them. White-only primaries shut Black voters out of the only elections that mattered in the one-party South. It took the Voting Rights Act of 1965, signed 95 years after the 15th Amendment, to outlaw these tactics and send federal registrars into counties that refused to comply.