Good leadership requires you to surround yourself with people of diverse perspectives who can disagree with you without fear of retaliation.

I think after Sandy Hook, when Obama went out, and he talked a lot about gun control and met with the parents, there was a sense that something was going to happen. But then, I guess, the power of special interests was greater than public sentiment.

He (William Howard Taft) had little patience with the unconscious arrogance of conscious wealth and financial success.

When you are an historian, there's probably nothing that matters more than to be recognized by your colleagues in your own profession. I was lucky enough to win the Pulitzer Prize for History. I had to give a talk right after that to some young people. The most important thing to tell them, I think, is that you can't ever know that it's going to turn out that way.

I think the most important advice is, a person doesn't have to find out right away. It's not like their first attempt at finding a profession is the only one they're going to find. I might well have gone down other paths, and it still might have been okay. But if you find something that you love, and if it keeps deepening with each new experience, then just stay with it.

You can't start out at 20 in whatever your profession is and say, "I want to win an Olympic medal," or "I want to become president," or "I want to win the Pulitzer Prize." If you love what you're doing, it's sort of a nice thing that happens toward the end of your career, or in the middle of your career. It is not the reason you were doing it. The reason you were doing it is because every day you wake up in the morning and you can't wait to learn something new.

I think with Lyndon Johnson, the most important thing I learned was that he never had the sense of security that comes from inside. It always depended on other people making him feel good about himself, which meant that he was always beholden, continually needing to succeed. He could never stop. There was such a restlessness in him.