Andrew Johnson and James Buchanan. James Buchanan, because he was voted out of office during the Lame Duck era of American Presidencies, allowed the South to revolt and secede and didn't do anything about it. Most historians believe he was the worst. Now Johnson, a Democrat from Tennessee, who Lincoln selected because it would show solidarity as the North was winning and trying to shore up Southern sentiments. When Lincoln died, the logical process that Lincoln put forward to return citizenship and self governance for the South was destroyed by Johnson. With an almost entirely Republican Congress fought with him, and when he didn't want to compromise, they enacted whatever reforms they wanted because they had enough votes to override vetoes. It was also at this time that very few southerners were allowed to vote, but almost all former slaves were, leading to a large number of educated former slaves to become senators and representatives.