In Defense of the Just War Tradition: A Critique of the Just War Revisionism of Jeff McMahan

In 2009, Jeff McMahan of the Ethics department at Oxford wrote a provocative book, Killing in War, critiquing just war theory as a viable moral construct for limiting war. He also summarized it in a two-part article for The New York Times Opinionator Blog (Part 1 and Part 2). His revisionist perspective that asserts the "principles of jus ad bellum [principles that distinguish just war from unjust war] apply not only to governments but also to individual soldiers, who in general ought not to fight in wars that are unjust."  

Without doubt, recent expressions of international violence, such as targeted assassinations, wartime actions in undeclared war zones, or the use contract mercenaries,  force philosophers of just war to pause and consider some, perhaps under-explored, nuances. However, contrary to the professor's beliefs, this does not require significant modification of the just war tradition.

Blackwater personnel escorting Paul Bremer, an American civil administrator, upon his arrival in Ramadi, Iraq, in March 2004. (Peter Andrews/Reuters)

McMahan's central premise is that a revisionist approach to just war theory uniting the moral codes defining the justice of going to war, jus ad bellum, and the just conduct of war, jus in bello, is significantly more plausible than the current system, which treats the two ideas separately. In the current construct, combatants are judged as moral equals, whether or not the war in which they are fighting is just.

In McMahan’s revisionist view, combatants would determine for themselves whether or not the war is just, and should choose not to fight in unjust wars. To capture the distinction, he uses two terms foreign to the traditional just war construct—just combatant and unjust combatant. This creates circularity in his argument, which undermines his intent. The labels of just combatant or unjust combatant would be applicable only if one accepts his revisionist system. Such labels do not apply when discussing the traditional system, because in that system they lack meaning (which seems to be the source of McMahan’s discontent). However, in using these terms in his argument, he unwittingly argues against his revisionist system by demonstrating the incoherence that ensues when such labels are used.

For example, he argues a sailor at Pearl Harbor on the morning of the 1941 Japanese attack has a right to not be attacked by the Japanese and loses this right when the attack begins. He says the only reason the sailor loses this right is because he was attacked. He concludes this is unacceptable because, "When the Japanese crews conduct their surprise attack, they act permissibly according to the [just war] Theory, even though their attack violates the principles of jus ad bellum."

This last statement most clearly demonstrates the circularity of the McMahan's argument, as well as why his revisionist approach is unacceptable. First, under the traditional construct, the sailor never lost his right to not be attacked. He retains that right, and this fact demonstrates the injustice of the decision to attack (given that Japanese decision to go to war was unjust). Second, the Japanese attacker did not, and cannot, violate the principles of jus ad bellum, because the principles address only the decision to go to war not the decisions in war. The first pilot to drop weapons on Pearl Harbor did not start the war. The war began when the Japanese political leaders declared war on America and ordered an attack. Third, the incoherence in the situation described by Professor McMahan is a direct result of attributing jus ad bellum responsibility to combatants, which is the necessary result of the revisionist view he supports. This purported inconsistency does not exist if the two codes are separate, as in the traditional system.

Also, it is clear McMahan expects more from the just war tradition than it is intended to provide. For instance, he says, "The Theory cannot offer any moral reason why a person ought not to fight in an unjust war, no matter how criminal." This suggests that all combatants should get to choose whether or not to fight, which historically is not the case. One of the base assumptions in the just war tradition is that all fight unwillingly, as Michael Walzer discusses in his influential book on the subject, Just and Unjust Wars. This assumption is an important one because it prevents atrocities. Under revisionist moral accountability, every combatant would rightly assume every other combatant on the field chose to fight. Worse, this entails that they can view their enemy as culpable in causing the war, because they bear the responsibility of the decision to go to war. In essence, they are no longer just the enemy, no longer moral equals—they are now criminals. It is important not to criminalize the enemy by default, because in doing so atrocities become more probable.

There is another problem for the professor in his desire that the just war tradition cohere with standard individual morality. While the distinction between jus ad bellum and jus in bello provides moral equality among combatants, jus in bello principles protect the distinction between combatants and civilians. Essentially, they set the boundaries between just killing and unjust killing in war. Combatant moral behavior must be distinctly different from civil moral behavior. It is difficult to imagine citizens of a common community, and sharing common spaces, utilizing an ethic that defines when it is appropriate to kill each other. Conversely, the rightly established, more stringent restrictions on killing in the civil community, if applied to combatants, would not permit the initiative required to win wars, thus prolonging them.

Also, contrary to Professor McMahan's belief, the jus in bello principles were not derived as a means for civilians to justify defending themselves against enemy combatants. Again, their intent is to protect the distinction between combatant and noncombatant and define unjust actions in war. Communities defer the responsibility for their collective defense to their combatants. Their right to protection in war is inherent in the title noncombatant, not in their right to action. The moment they "attack to defend," to use the professor's words, they cross the line from noncombatant to combatant and lose the protection the former title affords. While the required passivity on the part of civilians can be frustrating, it is essential if they are to retain its protection.

Charles I of England, with a divine hand moving his crown (National Portrait Gallery/Wikimedia)

Lastly, there are problems surrounding the just war tradition in contemporary conflict. However, they do not stem from the changing character or practice of war, as the professor suggests. The tradition still provides a viable means of determining just and unjust decisions to go to war, as well as just and unjust acts that take place during war. It also protects the distinction between combatants and noncombatants. Nevertheless, a problem does lie in Western ideas of relative morality and the unsteady bases on which we found our moral beliefs. Theologians who recognized the authority of God first articulated these principles. When philosophers removed divine authority as a basis for moral reasoning during the 17th and 18th centuries, the principles lost their transcendence and what was divine ought became simply ought. This problem will be magnified in any revisionist normative construct.

The efforts of just war philosophers, revisionist and traditional alike, are laudable. However, McMahan's revisionist just war theory creates more problems than it solves.


Paul Vicars is a staff officer at Air University. The views expressed are his own and do not reflect those of the Department of Defense or the U.S. Government.


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Header Image: We need a just war tradition that is clear and attempts to regulate modern warfare (AP)