I didn't pay my taxes for years.

Over the years, there's been case after case when there were very narrow decisions that had to be made about whether to launch nuclear weapons in serious cases. What is this guy [Donald Trump] going to do if his vaunted negotiating skills fail, if somebody doesn't do what he says? Is he going to say, "Okay we'll nuke them? We're done?"

The "end of history" has been proclaimed many times, always falsely.

If you want to scare people, you talk about evil.

If anybody thinks they should listen to me because I'm a professor at MIT, that's nonsense. You should decide whether something makes sense by its content, not by the letters after the name of the person who says it.

If the United States is accommodating, the North Koreans become accommodating. If the United States is hostile, they become hostile.

It's easy to put [serious threats] aside, and the media don't talk about them. Other things are more important. How am I going to put food on the table tomorrow? That's what I've got to worry about, and so on. It's very serious, but it's hard to bring out the enormity of these issues, when they do not have the dramatic character of something you can show in the movies, with a nuclear weapons falling and everything disappears.