What about Wilson? That naive jackass got well over 100,000 Americans killed in Europe because of his appeasement of and weakness toward Germany. Had TR's Bull Moose Party won, or Taft's Republicans, Germany would likely not have dared to sink our ships for fear of what would shortly be disembarking in Europe. Instead, the Germans had to find out the hard way that Americans weren't all as weak as Wilson - and "the hard way" cost us rivers of blood.
Here's another question: who was worse, Carter or Klintoon? I have trouble with this question, as they both have their own respective areas of "expertise."