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.

There is a radical and unprecedented shift [in war] that is part of the general transformation of civilization. First, understand that the past 150 years of warfare are totally unprecedented in that we introduced a breathtakingly inefficient technology: guns. In the First World War, and this is not an exaggeration, it took 10,000 rounds of ammunition to kill one person. Any given shot had a one in 10,000 probability of ending someone's life.

When you have the countries like Germany, China, and Russia decline, and be replaced by others, that's when systemic wars start. That's when it gets dangerous, because they haven't yet reached a balance. So Germany united in 1871 and all hell broke loose. Japan rose in the early 20th century, and then you had chaos. So we're looking at a systemic shift. Be ready for war.

Every theory I've seen that contains an explanation of war fails. I think they fail for the same reason that explanations of sex fail. War derives from things so deep and so complex, I'm thoroughly baffled by it at the end of the day.

I think there are worse things than war. For example, injustice.

Assad's mother was a terror. He was terrified of her and she kept saying to him, you're not like your father. That's interesting, but it's useless information. It doesn't tell me anything about how the first and second armored brigades are going to operate.

If you lose yourself to rage in the complexity of battle, you are going to be lost.