After a regime is removed, however, it is dangerous to leave a security vacuum.

Every math curriculum in the world is based on the idea of hand-calculating, and most of what you're teaching is how to calculate. And I think the resistance to this is very variable.

I think one has to say it's not just simply a matter of capturing people and holding them accountable, but removing the sanctuaries, removing the support systems...

The most striking thing is that even before Osama bin Laden was killed, he seemed largely irrelevant to the Arab Spring.

Donald Trump seems to be unconcerned about the Russian aggression in Ukraine. By doing this he tells them that they can go ahead and do what they are doing. That is dangerous.

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

It would be a huge mistake to abandon democracy promotion. Peaceful political change has been enormously successful in the past years in Eastern European countries as well as in countries like South Korea, South Africa, Chile and Indonesia. However, if possible, the use of force is something to avoid except in cases where genocide is threatened, like Bosnia or Libya or with regimes that threaten our security, like the Taliban and Saddam Hussein.