Lincoln's biggest mistakes were 1. Choosing Johnson as his VP. And 2. helping to solidify the supremacy of the federal government. Otherwise though, he performed feats that made the 10 presidents before him look like nothing, I wouldn't call Lincoln a bad president at all. Like many of our top five juggernauts that we learn about in school, there's a lot of imperfections that they don't tell us about, but still a damn good president.