The 15th Amendment to the United States Constitution, ratified in 1870, granted African American men the right to vote by prohibiting the federal and state governments from denying a citizen the right to vote based on race, color, or previous condition of servitude. It marked a significant step in the Reconstruction era's efforts to establish civil rights for former slaves, although its effectiveness was undermined by discriminatory practices like literacy tests and poll taxes until the Voting Rights Act of 1965.