I liked this bit a lot:
As Robert Caro wrote:
"We're taught Lord Acton's axiom: all power corrupts, absolute power corrupts absolutely. I believed that when I started these books, but I don't believe it's always true any more. Power doesn't always corrupt. Power can cleanse. What I believe is always true about power is that power always reveals. When you have enough power to do what you always wanted to do, then you see what the guy always wanted to do."