The Fifteenth Amendment to the U.S. Constitution reads:

Section 1. The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude.
Section 2. The Congress shall have power to enforce this article by appropriate legislation.

The Fifteenth Amendment was ratified by the states in 1870 and also gave Congress the power to enforce such rights against governments that sought to undermine this guarantee through the enactment of appropriate legislation. Enforcement was, however, difficult as states employed grandfather clauses and other eligibility requirements to maintain racial discrimination in the electoral process.

Source Citation: "Fifteenth Amendment." West's Encyclopedia of American Law. Eds. Jeffrey Lehman and Shirelle Phelps. Vol. 4. 2nd ed. Detroit: Gale, 2005. 1 pp. 13 vols. Gale Virtual Reference Library. Gale.