Jeff McMahan’s proposal—that the U.S. military adopt legal provisions for selective conscientious objection by active-duty soldiers—is compelling and should be taken seriously.

There is a risk, though, that the proposal will be misunderstood. McMahan describes a right to conscientious objection, an option apart from wrongfully obeying a command to fight in an unjust war or submitting to punishment. This seems to imply a right to opt out similar to that found in other morally charged domains such as health care. Think of the Jehovah’s Witness doctor who refuses to administer blood transfusions.

If a soldier had such a right, then the rightness of his refusal wouldn’t be the central issue. Instead, the central issue would be his sincerity, and the people who assessed his refusal would have to be agnostic about its merits. This is because the right to conscientious objection provides a protected sphere in which a person can act in ways he ought not to.

But this sort of right is not what McMahan has in mind. On McMahan’s proposal, the military wouldn’t be agnostic about soldiers’ reasons for refusing to fight. There would be tests for the plausibility of a soldier’s reasoning.

What this shows is that McMahan proposes to give soldiers not legal rights to refuse to fight in unjust wars but legal duties. Such duties are only legal rights in the sense that being required to act entails being permitted to.

There should be no penalty for successful conscientious objection. 

Consequently, despite McMahan’s claims to the contrary, there should be no penalty for successful conscientious objection even if a penalty would deter malingerers, because people should not be penalized for performing a legal and moral duty. We have a legal duty to pay our taxes, and there is no penalty for doing so. Instead there is a penalty for not doing so. Similarly, in some countries, people have a legal duty to vote, and there is no penalty for voting even though a penalty might deter people who would deliberately spoil a ballot or vote frivolously. By analogy, soldiers who honor the legal duty to refuse to fight in an unjust war should not be penalized but protected. And soldiers who fight in an unjust war should, in principle, be punished.

McMahan appropriately worries about the practicality of his proposal, which is why he calls for penalties. But, as he points out, soldiers tend to view the wars they fight in as just and tend to be animated by loyalty and deference. This means that it’s unlikely they would decide en masse, or even in small numbers, to refuse to fight in a war unless that war truly were unjust.

There is, of course, the problem of testing a soldier’s sincerity. But when a war is manifestly unjust, a soldier’s sincerity or insincerity in refusing to fight isn’t salient. Insincerity reflects poorly on his character, but not on his conformity with a legal duty to refuse to fight.

The testing of his sincerity might still have to be done for form’s sake. But that testing needn’t be as fallible as McMahan thinks because sincere objection has distinctive features that can be observed in a soldier’s behavior.

First, it is non-evasive. The sincere soldier is willing to bear the risks of being seen to refuse to fight, which include the risks of social censure and perceived disloyalty. He is willing to register his objection in advance of an action rather than on the ground, where panic may be a good explanation for a refusal to fight.

Second, his refusal is communicative. The sincere soldier tries to engage others in deliberation about the merits of his conviction. His efforts show that he believes his conviction is not only defensible but also worth defending despite the social and professional risks.

Now, how much good can this legal duty do given that, as McMahan notes, soldiers often lack or are denied relevant facts about wars, tend to trust their government and superiors, tend to believe their war is just, feel loyalty to their fellows, engage routinely in practices designed to train obedience, and tend to think that obedience is an overriding professional duty? Wouldn’t a legal duty to refuse be only a duty on the books that no one honors in practice?

To avoid this, the duty must be supplemented by mechanisms that mitigate the effects of peer pressure, loyalty, and deference. Those mechanisms could include independent channels whereby soldiers raise objections before officers who are not their direct commanders, avenues for temporarily objecting anonymously, education about legal duties and protections, forums for soldiers to debate the merits of a proposed war, refinement of training methods to temper soldiers’ automatic responses, independent advocacy bodies, independent adjudicatory bodies, increased connections with the civilian population, and ombudspersons for objectors. Such provisions could give teeth to the legal duty to refuse to fight in unjust wars and reduce the moral risks of voluntary enlistment.