Just Cause for War


  • Jeff McMahan

    1. Jeff McMahan is Professor of Philosophy at Rutgers University. He is the author of The Ethics of Killing: Problems at the Margins of Life (2002), and is presently working on a sequel provisionally called The Ethics of Killing: Self-Defense, War, and Punishment.
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      I am deeply grateful to Christian Barry, Allen Buchanan, David Lefkowitz, Larry May, Ron McClamrock, David Mellow, and Derek Parfit for penetrating comments on an earlier draft of this essay, and to Thomas Hurka for illuminating discussion.


The central contention of this essay is that a just cause for war is a wrong that is of a type that can make those responsible for it morally liable to military attack as a means of preventing or rectifying it. This claim has many implications that conflict with assumptions of the currently orthodox theory of the just war. Among the implications explored in the text are that the requirement of just cause is logically and morally prior to all the other requirements of a just war, that this requirement governs all phases of a war and not just the resort to war, that it is thus impermissible to continue to fight a war once the just cause or causes have been achieved, that it is impermissible to fight at all in a war that lacks a just cause, that just cause is a restriction on the type of aim that may be pursued by means of war and is not a matter of scale, that a war that lacks a just cause may be morally justified even if it is not just, and that a belligerent can pursue both just and unjust causes in the same war, which may then have elements or phases that are just and other elements or phases that are unjust.