Kaplan doesn't really advocate any standard pagan ethos. It isn't stoicism, epicureanism, or Aristotelian — some of the famous ancient ethical systems. Machiavelli figures prominently, but Machiavelli describes how a particular person can remain in power, not how nations should act, which is what Warrior Politics is about. What the book really promotes is the ethics of complete pragmatism: a compendium of approaches that have been successful in the past, across culture, time and location, but it fails to provide any kind of guide as to when to pick what strategy (or to put it in ethical terms, what's the hierarchy of values). And it's short on pointing out strategies that have worked well for America in the past, nor does it deal with the possibility that America, because it was explicitly founded on the ideals of the Declaration of Independence, cannot pursue a course of utter pragmatism but must have an irreducible minimum idealism in its foreign policy.

I essentially agree with the premises of Warrior Politics, but I don't know that it would persuade anyone who wasn't already in agreement with them. The book is too long for simply setting forth his ideas, and too short for explaining and defending them.