Read Robert Caro's excellent volumes about LBJ. You wouldn't think so, but they are real page turners. And yes, they will leave you with the impression that LBJ was not a wonderful person.
Jimmy Carter did some bad stuff too. From his Wikipedia page:
> During Carter's presidency, the U.S. continued to support Indonesia as a cold war ally, in spite of human rights violations in East Timor. The violations followed Indonesia's December 1975 invasion and occupation of East Timor. It did so even though antithetical to Carter's stated policy "of not selling weapons if it would exacerbate a potential conflict in a region of the world."