The man who hates war more than he hates the Nazis is a wicked man.

When I went to war, I did not go making geopolitical calculations. I went to war with a lust.

The British bombed German cities [during World War II] to keep the workers awake at night. So instead of dropping one bomb, we sent a thousand planes and, yes, we took out the factory sometimes, but we also took out the city. It reached the point where we wanted more efficient ways to destroy a city. The result was nuclear weapons.

But every time new powers emerge they have to find their balance. New powers are emerging, old powers are declining. It's not that process that's dangerous, it's the emerging position that's dangerous.

The Chinese central government will slowly and steadily lose authority while regional armies [gain power]. The Western powers are going to take sides to protect their investments - they have put billions of dollars into Shanghai. Their fear is that [these investments] are going to be expropriated by a warlord from the interior who will sweep down on Shanghai. They will try to form alliances with warlords to protect their concessions, and there will be a huge flow of weapons into China.

Constraint theory argues a number of things. First, that the impossible has to be identified. Second, that the actor is then constrained by circumstances to act a certain way. For example, should we invade ISIS? Can we invade ISIS? What would it take to invade ISIS? Once you ask that question you discover the price of that option and then you take a look at American politics and see that the country is probably not prepared to invest the 2 to 3 million people that it would take to defeat ISIS and the insurgency afterwards. All right, so that's not going to happen.

Italy is the fourth-largest economy in Europe and the eighth-largest economy in the world, and its banking system is collapsing. And Germany is desperate. It must maintain its standard of living. It can only do that with exports and Deutsche Bank is very exposed to Italian debt. But so is the rest of Europe.