The 15th Amendment extended suffrage to African American men in 1870 but was not enforced, allowing Southern states to prevent African Americans from voting through violence, taxes, literacy tests, and gerrymandering for over 90 years. The Civil Rights Act of 1964 and Voting Rights Act of 1965 made racial discrimination in voting illegal and suspended literacy tests, increasing African American voter turnout. The Voting Rights Act required states with a history of voter discrimination to get federal approval for any changes to election procedures to prevent continued disenfranchisement.