I'm not really sure, but I do remember my parents *hated* Carter. I remember distinctly sometime in the '90s thinking "Look at all the amazing things Carter has done with himself after being president. I always thought he was an asshole!"
Johnson was a sociopath, who gave us Medicare, Medicaid, desegregation, and “standardization of computer communication.”
Your point made, however: it takes a true monster to survive American politics.