How did the 13th, 14th, and 15th amendments affect slavery after the Civil War?

Slavery was abolished and African-Americans were protected.

13th amendment abolished slavery. 14th granted citizens protection. 15th was male suffrage.

However, during the Reconstruction period in the South, African-Americans were not always ensured these rights as legal enforcement would almost always turn a blind eye. Also around this time the Klu Klux Klan emerged.