I believe marriage is between a man and a woman. I am not in favor of gay marriage. But when you start playing around with constitutions, just to prohibit somebody who cares about another person, it just seems to me that's not what America's about. Usually, our constitutions expand liberties, they don't contract them.

The one thing I've said to [Donald Trump] directly, and I would advise my Republican friends in Congress and supporters around the country, is just make sure that, as we go forward certain norms, certain institutional traditions don't get eroded, because there's a reason they're in place.

I would love to see an America where race is understood in the same way that the ethnic diversity of the white population is understood.

I don't have to negotiate an arms agreement with Great Britain or with France.

In America, we want a peaceful planet. We want people to be able to enjoy their lives and know they're going to have a bright and prosperous future, not be at war. That's our purpose.

Part of American leadership is making sure that we're doing nation building here at home. That will help us maintain the kind of American leadership that we need.

There's no doubt that probably at least once a week, maybe once a day, I said, "Ah, I should have done that better."