Worst President Ever
Buchanan was worst. He allowed his Secretary of War to ship Federal artillery to the south, where it could be used against the national government. The civil war was his creation.
FDR was second worst, for his inaction when Germany could have been stopped by very small forces, and his massive increase of government programs, which lengthened the depression, weakening the US when we needed to be strong. His agriculture programs, limiting US crop planting and food reserves, led to starvation of millions after WWII was over.
Wilson also is right up there, for is refusal to support the democratic nations, or to build up US defenses despite a world at war.
I would put Truman as 4th worst, for permitting Soviet opression in Eastern Europe, and publicly putting Korea outside the zone of interest, then being surprised when the communists accepted his offer.
Carter as 5th worse.
D
Worst President Ever
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Clinton comes close.
And it's a tie for the worst ex-president. He and Bubba are neck and neck.