Jeff McMahan’s challenge to the just war tradition deserves careful consideration. His arguments prove unpersuasive, however, and he misrepresents both the role of the military in society and troops’ responsibility for foreign policy decisions. His proposal could do real harm to those who choose military service and to our democracy.

In building his case for a right of selective conscientious objection—the right of individual members of the military to opt out of their service if they judge a particular conflict to be unjust—McMahan urges us to abandon basic tenets of the just war tradition, which asserts that one can and should separate the justice of the decision to go to war (jus ad bellum) from the justice of the means by which a war is prosecuted (jus in bello). The tradition holds members of the military responsible for the latter, but not for the former. These distinctions are touchstones of international law.

McMahan, in contrast, wants to hold the warriors themselves responsible if they fight for an unjust cause, even if they do so using just means. If such accountability did exist, then it would indeed be unethical to prevent members of our all-volunteer force in the United States from opting out of wars they feel are not worth the risk of moral—and, if McMahan and others had their way, legal—liability. Under the current rules, they can refuse to serve but may suffer penalties for doing so.

If our courts put innocent people to death, we do not try the executioners.

McMahan’s arguments depend on convincing us that direct analogies can be drawn between killing in war and killing in domestic settings. I agree with McMahan that war is not a separate sphere where different moral principles apply. It is possible, for example, to commit murder in the context of war. However, a combatant who kills an enemy combatant is neither a murderer nor strongly analogous to one. This is true not because war has its own morality but because murder is an individual act done for personal reasons and requiring a certain state of mind (known in the law as mens rea or “guilty mind”). Killing in war, however, is an act of the state. As I explain in The Code of the Warrior (2003), “When they are trained for war, warriors are given a mandate by their society to take lives. But they must learn to take only certain lives in certain ways, at certain times, and for certain reasons.” 

The decision to use military force is made by elected officials who (in theory, at least) represent the will of the people. Members of the military can, like all citizens, vote for the political representation they would prefer. But when the elections are over, they cannot mutiny against the policies of particular leaders and remain in military service.

An instructive analogy, frequently cited by just war theorists, is between warriors and state executioners. In the criminal justice system, executioners are not expected to pass independent judgment on death penalty cases; indeed it is inappropriate for them to do so. It would undermine the rule of law if executioners could decide to set condemned men and women free, and it would be murder if an executioner decided to use the state’s equipment to kill someone not sentenced by the courts.

If our courts fail and innocent people are put to death, we do not try the executioners for murder. They are unlikely to be held accountable in any way for the injustice, although we may fault judges or juries or the system itself.

McMahan insists that it is wrong for any individual to take on “the risk of becoming an instrument of injustice.” Yet he argues elsewhere that in order to have the best chance of achieving justice most of the time, certain roles in the justice system must be faithfully fulfilled by individuals, regardless of their personal feelings or convictions about a particular case, citing defense lawyers as an example (they must use all their skill to defend even a person they believe to be guilty).

Why, then, does McMahan not accept a comparable role for warriors? The answer is that he is dramatically less sanguine about leaving decisions about war to the state, insisting that “no government’s moral judgments about its own resort to war can be expected to be more reliable than those of a well-informed, impartial, and morally scrupulous individual.”

McMahan’s frustration with political decision-making is certainly understandable. But to transfer jus ad bellum responsibility to the already burdened-almost-beyond-bearing shoulders of military service members is unacceptable. If our country is fighting too many unjust wars, we should not require that our warriors change foreign policy, but rather insist that voters—and perhaps the International Criminal Court—hold our political leaders accountable.