Why Did Reconstruction’s Amendments Bring Different Results Across the South?

The 13th, 14th, and 15th Amendments changed the Constitution after the Civil War, but their protections were not experienced equally or consistently across the former Confederacy. What explains the gap between the rights established in law and how those rights were enforced in different states?

I’m especially interested in how federal enforcement, local resistance, and changes in national political priorities shaped that uneven record.