"a disastrous president, Andrew Johnson"
President Andrew Johnson
Public DomainPresident Andrew Johnson

Andrew Johnson (1808-1875) became US President when Abraham Lincoln was assassinated in 1865. 

While Lincoln's harsh policies towards the South had made him unpopular there but popular in the northern states, Johnson's more lenient approach angered many in the North while still not assuaging residual bitterness in the South.  The opposition to Johnson's policies led to deep division within the government, which limited the amount that was actually achieved for the Reconstruction effort.