During the era of Reconstruction, African-Americans were able to gain some political opportunities through the passing of the 15th amendment.
The 15th amendment guarantees the right of African-American men to vote in elections. This law was then enforced by the federal government during the Reconstruction era. Along with this, African-American citizens go to run for office during this time. The first two African-American men in Congress, Hiram Revels and Joseph Rainey, were both elected to Congress during the era of Reconstruction.