There is too large a divergence at the moment in the interests and values of the world's most powerful states.

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

There is always the risk that a conflagration in the Middle East becomes larger and more dangerous. In this scenario, we discover that the Arab Spring was merely the prelude to a deeper and much farther-reaching upheaval in the region that has greater impact on countries like Iran and Saudi Arabia.

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.

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.

NASA is increasingly not the future of space exploration. I love the fact that we have private sector folks devoting a lot of money to stimulate innovation in space technology.

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.