The 15th Amendment.
Explanation:
The 15th Amendment gave voting rights to Americans regardless of skin color or race. This also made sure to secure the voting rights of people who were former slaves.
This amendment was the first to clarify who could vote. It also went along with both the 13th Amendment and the 14th Amendment. The 13th Amendment properly ended slavery, outlawing it in the United States. The 14th Amendment granted former slaves the rights of U.S. citizens. Finally, as I stated above, the 15th Amendment gave voting rights to Americans regardless of skin color or race.
