The 15th 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 amendment gave the former slaves the right to vote.

I think that this picture sums up the amendment well.

The south still found ways to stop blacks from voting