15th Amendment: The 15th Amendment to the U.S. Constitution prohibits the federal government and each state from denying a citizen the right to vote based on that citizen's 'race, color, or previous condition of servitude.'
Literacy Tests: Discriminatory voting requirements that required prospective voters to pass literacy tests or demonstrate a certain level of education, which were used to disenfranchise African American and other minority voters.
Shelby County v. Holder: A 2013 Supreme Court decision that struck down the preclearance requirement of the Voting Rights Act, which had required certain states and local governments with histories of discrimination to obtain federal approval before changing their voting procedures.