Most of the people who were responsible for 9/11 are now in custody or have been killed. But there are others, and they plot and they plan, and they hope to pull it off again. And while we have to be right 100 percent of the time, they only have to be right once. So there's no way to overreact to that.

I'm actually genuinely optimistic about the United States and what's possible in the United States. And when you're out here, you see Americans across racial and economic and socioeconomic lines working together. And you maybe get a little bit less cynical than when you sit in the seat of kind of the epicenter of it all.

[My favorite dish to cook] is fried chicken, and by the way I'm good at it, too. I make really good fried chicken.

Human beings are not perfect. Their institutions are not perfect, but they have to keep trying. And America has to help people keep trying.

I'm a great believer in the fact that as you get to know someone, it matters not what religious background they have, or what their nationality is, or where they came from. And I think that's how Americans really do relate to each other on a personal level.

I'm very glad my mother didn't let me quit piano lessons at age 10. She said I wasn't old enough or good enough to make that decision, and she was right. I remember at the time I was shocked. I did not like that my mother said those things to me. But when I got a chance to play with Yo-Yo Ma or more recently with Aretha Franklin, I thought, I'm really glad she said what she did.

If you're always in the company of people who agree with you, you're going to think of people who don't agree with you as venal or stupid. I constantly tell my students that if they're in the company of people who always say "amen" to what you say, find other company. And that is the source of illiberalism, when you are unable to listen to someone who thinks differently. That's when democracies are in trouble.