I think it was Nancy that got to him, that's who. He had the charisma, but really wasn't a very bright person. Probably too much football. But Nancy had Ginny Thomas vibes all over her. Controlling and manipulative from the background the whole time and was the defacto president the last couple of years of his term while Reagan lost his mind. Greed is a powerful motivator and when you get that kind of power you start to care less and less about the common man and just more for how much more money and power you can accumulate.