After the Civil War two amendments were added to the U.S. Constitution that explicitly guaranteed the rights of African Americans as citizens. The 14th Amendment (ratified in 1868) prohibited states from denying the "equal protection" of its laws to any person. The 15th Amendment to the U.S. Constitution (ratified in 1870) affirmed that "[t]he 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.