Fifteenth Amendment

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.

This was passed by Congress and sent to the states for ratification in 1869, and ratified in 1870. This was the last of the Reconstruction amendments after the Civil War. There would not be any new amendments until the 20th century.