Aggression is morally as well as physically coercive, and that is one of the most important things about it. The comparison of international to civil order is crucial to the theory of aggression. The theory of aggression restates the old doctrine of the just war: it explains when fighting is a crime and when it is permissible, perhaps even morally desirable. Aggression is a singular and undifferentiated crime because, in all its forms, it challenges rights that are worth dying for. If states actually do possess rights more or less as individuals do, then it is possible to imagine a society among them more or less like the society of individuals. When the analogy is made explicit, as it often is among the lawyers, the world of states takes on the shape of a political society the character of which is entirely accessible through such notions as crime and punishment, self-defense, and law enforcement.