The original goals of Reconstruction were two-fold. The rebuilding and reorganization of the southern states and their economies and the incorporation of newly-freed slaves into American society. These aims were lofty, and were abandon before they were complete. When the war ended in 1865, Reconstruction was placed in the hands of Lincoln’s successor, Andrew Johnson. A southerner, former slave owner, and racist, Johnson ignored the needs of African-Americans and focused only on a quick and very basic reintegration of southern states into the Union. As a result, former slave owners and ex-Confederates regained power, and the systematic suppression of free blacks began.
Horrified at tales of mass race riots and lynching, Radical Republicans in congress tried their best to address the needs of African-Americans, but Johnson vetoed every bill as unnecessary. Eventually he was impeached, and although he wasn’t removed, his power was broken and congress took over. Under the Radical Republicans in congress, the lot of African-Americans in the south improved. Military districts were created, armies were sent to combat violence and terrorism while assistance for African Americans looking to vote was also sent. When Grant was elected in 1868, further federal protection was extended to African-Americans in the form of constitutional amendments.
Eventually however, the country tired of Reconstruction. The money, constant news of violence, presence of the army in the south and racially skewed spending. By the mid 1870’s the country was ready for the whole process to be over as quickly as possible, so when the opportunity to end Reconstruction ended, the north agreed to pass the buck to the same southern governments who curtailed the rights of African-Americans. So the process of Reconstruction was abandon early, and was never able to really take hold and work out.