After the passage of the fifteenth amendment, congress assumed authority over reconstruction. how did congressional reconstruction efforts affect the lives of african americans in the south?

Improved for a time--Congressional Reconstruction outlawed the laws restricting blacks. 

During Congressional Reconstruction, the Black Codes were lifted and the KKK outlawed. Blacks were able to vote and gain access to political positions. Blacks were able to purchase land and establish institutions for the black community. 

What is the