I may have disagreed with him on things, but the only Rat I had some respect for is Harry Truman.
He did one good thing with dropping the big ones on Japan, but his failure to tackle the epic-level Soviet and Soviet sympathizer infestation of the federal government (for starters) and not allowing MacArthur to take out Mao in favor of Chiang kicked off all the problems that would plague us in foreign policy to this day. Disastrous incompetence.