I think the best way to control a population is to urbanize and to educate women. We have seen historically in many, many countries that once women are educated and have opportunities, and that happens when they live in cities and once they improve their economies, they no longer want to have eight kids. They want to have one or two or maybe three. And that is much more sustainable for them because they have other opportunities.

We don't gaze into a crystal ball. I do not believe that we predict things. I think political science is bad at prediction. I think what we really do well is in a number of instances where politics matters, we can do a better job of tell you what is happening now, than other people. So, we can look at Syria today. We can look at the Eurozone today. And we can look at areas where politics is a driver and we can give you a pretty good sense in those areas of here is how to understand today.

The two world wars boosted American power and devastated potential rivals to an extent that could not have lasted more than a few decades.

I would rather people not smoke. I certainly appreciate the fact that smoking is not legal in restaurants and bars. That used to stop me from going out at night because you'd go someplace and your clothes would reek and you wouldn't enjoy the experience and that affects your rights. It's always a question. Whenever you are talking about these issues, it's not a question of restricting rights. It's a question of restricting whose rights, and providing for whose rights and that's a tricky balance.

Whether it is gun control lobby, health care lobby, or abortion, pro-choice lobby, whatever it is, people are always trying to say that it is about restricting rights and they are never really prepared to talk about what the honest tradeoffs are. One of the things we need to do a better job of is actually painting those tradeoffs.

Climate is a global issue. Coal is still the energy that is being used more than anything else to make electricity. The United States is using less as we're turning more to gas. But, around the world, that's what they're using.

I think graffiti is part of Berlin culture. You think about what the Berlin wall meant and how visible that was in everyone's life. How it was a part of their very identity.