Who is reconstruction plan was toughest in the south?

The toughest reconstruction plan in the South was implemented by Congress, particularly through the Radical Republicans. They sought to impose strict measures to ensure civil rights for freed slaves and to reshape Southern society, including military oversight and the requirement for states to ratify the 14th Amendment. This approach faced significant resistance from Southern whites and led to tensions, violence, and the establishment of groups like the Ku Klux Klan. Their efforts aimed to fundamentally alter the power dynamics in the South, making it one of the most contentious periods in American history.