This was a great article! I was particularly heartened by your insight that the same situation gave rise to both Buchanan and Lincoln. So I checked some of the other bad presidents.

The order of presidents went Pierce (42nd), Buchanan (44th), Lincoln (1st), Johnson (43rd).

So the same situation (tensions between north and south) gave rise to not only the best president (Lincoln), but the 3 worst presidents (Pierce, Johnson, and Buchanan).

All of a sudden, things look a lot less optimistic.