The United States is not longer going to be the world's policemen and our days of determining you're in or you're out around the world no matter what the level of direct American interest or connection are going to be very limited. Increasingly, Africa will be doing that.

I don't take things off. I either check things off or I add things.

Berlin is still a very edgy place, a very cosmopolitan place. It's a place where completely different ideas and cultures come together and clash in a very warm way. In a very warm-hearted way. It's a very young city. It's a vibrant city. It's an exciting city. It's a city that's also scarred by history. I think that's to be celebrated and graffiti is to be celebrated. Graffiti in Berlin is very different than when they spray something on the wall dividing the west bank and Israel. And should be treated as such in Berlin.

I don't see a coherent global order anywhere on the horizon.

In the nearer term, the likeliest source of risk is a conflict between China and the U.S. These are now the two largest economies in the world, and the combination of their economic interdependence, the sharp differences in their political and economic values, and the growing divergence in their interests makes this relationship potentially dangerous for everyone who might be affected by it - which means pretty much everyone.

I absolutely am an environmentalist. I am probably more of an environmentalist than most people who live in the world, but I think that comes from my position in the world and that doesn't make me a better person.

Everything today is "transient." Technology and its ability to empower actors large and small evolve so quickly that we have to get used to living in a world that exists in a more or less constant state of flux.