One of the great weaknesses of journalists is they interview people and they think that's important. They think that they are going to show them their true hand. But more to the point, they're trapped.

If you go through the list of things that are not possible you're left with a very finite amount of possibilities. The fancy name for this is constraint theory. It's a nonquantitative model, but it's a field of mathematics.

War is an extraordinary condition to be in - to be, for example, in the combat information center of a warship [and behaving] as though you were merely processing credit card applications. [Instead,] the information you're processing is that an incoming missile is 15 kilometers away, now 10 kilometers away, now 5 kilometers. You have to separate yourself psychologically from the fact that your mortal existence may well end. That is the ancient reality of war.

One of the great famines in human history took place during the Chinese Cultural Revolution. [At the same time] Western journalists were reporting how marvelously Chinese society was working. We know so little [about what happens in China].

The warrior must continue to make decisions in the face of extreme circumstances. He cannot afford to get angry or frightened.

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.

It has always struck me as the world's great fortune that the two great superpowers were the United States and the Soviet Union, who managed the Cold War with meticulous care in retrospect. Imagine the European diplomats of 1914 or 1938 armed with nuclear weapons. It is easy to believe they would not have been as cautious.