Long Story Short
As any kid can tell you destroying something is the "fun" part, putting it back together again is much more difficult. In the aftermath of the Civil War the South had been thoroughly defeated. Slavery was dead and the economy was in ruins. The North celebrated while southerners stewed in their humiliation. With Republicans in control of the government coming up with a plan for bringing the southern states back into the Union should have been simple. But soon Congress found itself fighting against their own president over how harshly the traitors should be punished and what the future would look like for the newly freed slaves. Reconstruction should have been a time to set things right but instead it turned into a train wreck.