I told my father I had to try political science for a year. He thought I was throwing my life away.

One of the things that ultimately led me to leave mathematics and go into political science was thinking I could prevent nuclear war.

That sense of what happened in Europe in World War II has shaped a lot of my views.

We did not go to war in Afghanistan or in Iraq to, quote, 'impose democracy.' We went to war in both places because we saw those regimes as a threat to the United States.

I mean, we're going to probably debate the Iraq war for at least as long as I'm alive.