When you're young and going to war, it's a genuinely exciting moment. You are going to risk yourself. On the battlefield, you are suddenly free. You realize: I'm here, I'm in it. Exaltation. Suddenly you're hit by another extraordinary feeling: my God, I can be killed. And: will I embarrass myself? It's like you're in a kaleidoscope and all of these extraordinary feelings are zipping by.

Constraint theory asks: What is the price for doing this? Now one way around constraint theory is declaring your enemy crazy. Crazy and stupid are not concepts used in forecasting. When people say they're really stupid or they're crazy, that's laziness. That means I don't want to think through their position or about what they're really going to do.

With the decline of American interests in the outcome of this region, there is no glue holding it together. And the countries in this region are invented ... The last guarantor of the region's borders was the United States, and the US has basically said "the hell with it." What you're really having is the collapse of nation-states because they're not nations. They're only states.

Wars are times of intense technological transformation, because societies invest - sometimes with extensive borrowing - when and where matters of life and death are at stake.

There is no difference in a country between military, economic, and political affairs. It's useful for Business Insider to divide things that way. That's useful for a college program. But a country is a country. How do you understand China's economy without China's army? If you take these all into account you're ready to explain a question like, "How come the US doesn't have a debt problem?"

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.

One definition of the wicked is that they will resort to whatever means are necessary to achieve their ends. Therefore, if those who oppose wickedness don't learn the art of war, they will be helpless.