There is more than one moral question to be asked about any complex political issue, and asking the wrong question generally gets us unsatisfying results. What makes a question the right one to ask, I think, depends most frequently upon the context in which it is asked; a question might be fully appropriate in one institutional or argumentative context, but misleading or obfuscating in another. Foundational questions about justice under ideal circumstances might be largely irrelevant for certain applied issues of political practice, for instance; and, similarly, practical issues can sometimes be usefully ignored where we are considering fundamental issues of political justice. Getting the question right, then, is the first step towards getting right answers.

This is relevant, I think, to our understanding of the moral issues surrounding preventive war. We have good reason to ask whether it is ever morally permissible for us to engage in preventive warfare – which I understand, along with most other commentators, as being warfare in the name of self-defense that lacks the “imminent threat” requirement of preemptive warfare as currently defined in international law. We should, however, begin by clarifying which of the several moral questions available to us is the one we are now asking. I think we might distinguish at least two possible questions, here – I suspect we could ask any number, but I will discuss only these. The first is what might be called the institutional question: what form of international laws or norms ought to be developed to constrain preventive warfare? This question begins with the idea that we are collectively deciding, together with whatever other states or international institutions we want to include, on a set of rules to guide our deliberations surrounding appropriate forms of military intervention.