The Fifteenth Amendment

The Fifteenth Amendment (Amendment XV) to the United States Constitution prohibits the federal and state governments from denying a citizen the right to vote-based on that citizen’s “race, color, or previous condition of servitude”. It was ratified on February 3, 1870, as the third and last of the Reconstruction Amendments.
In the final years of the American Civil War and the Reconstruction Era that followed, Congress repeatedly debated the rights of the millions of black former slaves. By 1869, amendments had been passed to abolish slavery and provide citizenship and equal protection under the laws, but the narrow election of Ulysses S. Grant to the presidency in 1868 convinced a majority of Republicans that protecting the franchise of black voters was important for the party’s future. After rejecting more sweeping versions of a suffrage amendment, Congress proposed a compromise amendment banning franchise restrictions on the basis of race, color, or previous servitude on February 26, 1869.
The amendment survived a difficult ratification fight and was adopted on March 30, 1870.United States Supreme Court decisions in the late nineteenth century interpreted the amendment narrowly, and by 1910, most black voters in the South faced obstacles such as poll taxes and literacy tests, from which white voters were exempted by grandfather clauses. A system of whites-only primaries and violent reprisals by groups such as the Ku Klux Klan also suppressed black participation.In the twentieth century, the Court interpreted the amendment more broadly, striking down grandfather clauses in Guinn v. United States (1915) and dismantling the white primary system in the “Texas primary cases” (1927–1953).

Along with later measures such as the Twenty-fourth Amendment, which forbade poll taxes in federal elections, and Harper v. Virginia State Board of Elections (1966), which forbade poll taxes in state elections, these decisions significantly increased black participation in the American political system.