This article addresses a previously overlooked problem in the ethics of defensive killing. Everyone agrees that defensive killing can only be justified when it is necessary. But necessary for what? That seemingly simple question turns out to be surprisingly difficult to answer. Imagine Attacker is trying to kill Victim, and the only way one could save Victim is by killing Attacker. It would seem that, in such a case, killing is necessary. But now suppose there is some other innocent person, (...) suffering some entirely distinct threat, whose life one could save instead. Is killing still necessary? The seemingly obvious answer is “yes.” Killing is necessary since it is the only means to achieve the goal that stands to justify killing. The problem with this answer is that it presupposes a certain description of that goal as something like “saving Victim’s life” or “saving Victim’s life from Attacker.” Other descriptions are plausible, such as “saving a life.” On that latter description, killing is unnecessary in this case. The problem we are encountering is the problem of finding the right description of the goal of killing. Call this the “description problem.” This article sets out to solve the description problem and arrives at a radical conclusion. In a variety of cases, we should describe the goal of killing in broad terms, without reference to a specific victim or a specific threat. These broad descriptions—such as “saving a life”—make it easier to find relevant alternatives. Killing, it turns out, is much harder to justify than we might otherwise have thought. (shrink)