The amendment gave Black men the vote on paper. During Reconstruction, Black voters elected hundreds of Black officials, including the first Black members of Congress. The amendment did not cover women, who won the vote with the Nineteenth Amendment in 1920.
After federal troops left the South in 1877, states rewrote their laws to get around it. Mississippi's 1890 constitution added a poll tax and a literacy test. Other states added grandfather clauses, white primaries and residency rules. White mobs and officials used violence and threats against Black people who tried to register.
The Voting Rights Act of 1965 finally gave the Fifteenth Amendment teeth by banning literacy tests and requiring federal approval of voting changes in places with histories of discrimination. The Supreme Court struck down the formula for that approval in Shelby County v. Holder in 2013, and many states passed new voting restrictions afterward.