The limits of liability in war
Keywords: Just war theory
Moral tragedy
Liability
Defensive harm
Moral equality of combatants

This doctoral thesis addresses questions in contemporary just war theory about the relationship between a combatant’s moral liability to be killed and an opposing combatant’s moral permission, justification, or obligation to kill her. It is a thesis by four relatively independent but thematically interrelated papers. Following a brief integrative chapter, each substantive paper addresses a different question in contemporary just war theory, and each relates, to one degree or another, to a combatant’s liability to be killed in war.
Just War Traditions and Revisions.
In this paper I distinguish between exceptionalist-collectivist and reductivist-individualist approaches to just war theory. I argue against the former and for the latter by appeal to a number of real-world cases. Ultimately, I argue that on a reductivist-individualist account, the set of liable persons and the set of military members who fight an unjust war overlap to a greater degree than might first appear.
Duty Killing and a New Moral Equality of Combatants.
In this paper, I argue that one does not become liable to defensive harm if one is epistemically justified in believing that one acts on a moral obligation. By extension, even on a responsibility account of liability, combatants on both the just side and the unjust side of a war might remain immune to attack and therefore be morally equivalent.
Continuing Threats in War.
By “continuing threat,” I mean one in which an unjust attacker both continuously harms and continuously threatens to harm a victim. According to this definition, victims of kidnapping, hostages, and those unjustly imprisoned are, all else equal, victims of continuing threats of harm. I argue that war consists of, inter alia, continuing threats of harm and threats of this kind can have a decisive effect on the proportionality calculus and therefore on liability to harm.
Reasons Not to Kill in War.
The language of rights can provide only an incomplete account of the moral costs of killing in war. When the person who is killed is liable to be killed, her rights have neither been violated nor infringed. And yet, her death is still morally bad in an objective sense. Some have argued that this objective moral badness is discounted in liability cases. In this paper I argue that the objective moral badness of death obtains in liability cases and is not discounted. Thus, if lethal harm is justified, the moral badness of death must be outweighed even in liability cases. On this view, therefore, liability-based justifications and lesser-evil justifications for defensive harming are structurally similar. The upshot of this view is that the objective badness of a combatant’s death—even the death of an unjust combatant—is included in the moral costs of war.
Conclusion.
Finally, in a brief concluding chapter, I explain how each of the substantive papers relates to theme of liability and accounting for the moral costs of war; I address an important distinction between moral harm and moral tragedy; and, where appropriate, I point out the practical implications of the various papers.