Abraham Lincoln started planning for the reconstruction of the South during the Civil War as Union soldiers occupied huge areas of the South. He wanted to bring the Nation back together as quickly as possible and in December 1863 he offered his plan for Reconstruction which required that the States new constitutions prohibit slavery.
During the reconstruction period, blacks who were legally free, weren't treated as such. Were they really free? Were the Black Codes meant to bring slavery back? Did slavery ever end? These are some of the things that we, today think about reconstruction, and what blacks thought.
Reconstruction ended because citizens gave up on racial equality for blacks in the South (or anywhere, for that matter). These fears and questions that came about became too much, and people doubted the hard work they had given would prosper, and that freedom for all wouldn't be a right.