I don't know whether or not his model is true, but the US hasn't had a period without some kind of military conflict for more than like 20 years. Before World

I don't know whether or not his model is true, but the US hasn't had a period without some kind of military conflict for more than like 20 years. Before World War I many people believed a major European war was impossible. There had been such a long period of peace, and there were arguments that prosperity and economic inter-dependency discouraged it.