David Luban, in a paper on preventive war that I will discuss directly later (download from SSRN here), characterizes the divide of moral theories of war using the ordinary distinction in ethics between rights based theories, such as Walzer's, and consequentialist theories. One example of a consequentialist theory of jus ad bellum, resort to force moral theory, he observes, is the justification for a no-first-use-of-force rule in the general conception of the UN. Consequentialism - reducing the incidence of war - rather than Walzer's defense of sovereign political rights argument, according to Luban, is the actual moral basis of the UN charter on the use of force. Leaving aside whether Luban is right about that for a later discussion, it seems to me a better way to characterize the debate over moral theories about war as being
- nonmoral, such as what I described as amoral realism.
- consequentialist, including various versions of what I described as moral realism and with varying degrees of realism built in.
- rights based theories of the just war, including both Walzer's theory of self-determination, sovereignty, defense of political community, and resistance to aggression; but also more traditional Christian theories from natural law.
- pacifism and nonviolence, rooted either deontologically (e.g., a command from God), or consequentially, as in a thoroughly realist account of the horrors of any war outweighing anything else.
- the positive law domestic analogy.
I'm now thinking it makes the most sense to key off the traditional division in moral philosophy of consequentialism and rights based theories, and then fit realism into it, rather than sticking with Walzer's debate between realism and just war theory. The category of realism seems to me to be too heterogenous to be very useful in categorizing moral responses to the question of war. It works for Walzer in the context of a more narrowly focused essay, but doesn't seem to me the conceptually comprehensive approach.