The 15th Amendment to the U.S. Constitution was the last of the three Reconstruction Amendments passed after the Civil War. The 13th Amendment abolished slavery, the 14th Amendment granted citizenship to former slaves, and the 15th Amendment gave black male citizens the right to vote.
More explicitly, the 15th Amendment declared that the right to vote could not be denied based on a citizens race, color, or status as a former slave. The original version of the amendment also included the right to hold public office, but this guarantee was dropped to make ratification of the amendment easier. Congress passed the amendment on February 26, 1869, and it was ratified by the states as of February 3, 1870.
In hindsight, we know that the 15th Amendment was only a first step in establishing voter equality. It would be more than a century before black Americans, women, and other disenfranchised groups could participate fully in American civic life.
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.
The Congress shall have power to enforce this article by appropriate legislation.