Despite a recent explosion of interest in the ethics of armed conflict, the traditional just war criterion that war be waged by a “legitimate authority” has received relatively little attention. Moreover, of those theorists who have addressed the criterion, many are deeply skeptical about its moral significance. This article aims to add some clarity and precision to the authority criterion and the debates surrounding it, and to suggest that this skepticism may be too quick. The first section analyzes the authority criterion and reveals that there are at least two distinct moral claims associated with it, each requiring separate evaluation. The second section outlines an increasingly influential “reductivist” approach to just war theory, explaining how this approach grounds powerful objections to the authority criterion. The third section sketches the most promising strategies for providing a qualified defense of authority, while acknowledging the further questions and complications these strategies raise. Importantly, the article aims to rehabilitate the authority criterion from within a broadly reductivist view.

This article explores how political authority is conceived and how we attempt to make sense of its legitimacy in a world that we imagine made of relatively equal and autonomous individuals who are members of multiple collective agencies. One such way is the Razian “Service Conception” of authority. This conception suffers from a variety of internal weaknesses and shortcomings. More importantly, while the Service Conception may be promoted as a normatively appealing theory of authority, it does not appear to fit the description of the central case of practical authority or, at least, it does not exhaust the list of central cases. Indeed, political authorities are often justified by self-assertive reasons that bind the subject to the authority claimant. Such cases are what we call “existential authorities”, as opposed to "functional authorities" associated with the Service Conception. The interplay between those types of authorities and their respective background assumptions forces us to take seriously the perceptions that subjects have of the nature of authority claimants as such perceptions will determine the attitudes of the subjects towards the directives issued by the authority claimants. We must therefore be able to distinguish between institutions meant to embody collective identities – “existential communities” – from institutions perceived as mere “functional regimes”. Indeed, the nature of the standards used to evaluate the actions and powers of each will differ accordingly.