The United States has taken a number of morally objectionable positions regarding the lawful conduct of armed conflict over the years. Among those positions, it still claims the legal right to attack civilians, objects indispensable to their survival, and their natural environment by way of reprisal, that is, in response to violations of the law of armed conflict by enemy armed forces. The Biden administration could and should renounce this position. It may soon have an opportunity to do so.

It’s important to distinguish between two kinds of reprisal at the outset. International law prohibits “armed reprisals,” that is, the resort to armed force in response to a past legal wrong, including an armed attack that is clearly over. For discussion of armed reprisals, see here, here, and here. In contrast, the law of armed conflict governs “belligerent reprisals,” that is, acts that would normally violate the law of armed conflict undertaken in response to prior violations of the law of armed conflict by enemy armed forces. This essay is concerned with belligerent reprisals.

To see the difference, consider a State exercising its right of self-defense against an ongoing armed attack by another State. Since the armed attack is ongoing, the use of force in response amounts to self-defense and not an armed reprisal. Now suppose the aggressor State captures and inhumanely treats some of the defending State’s soldiers. Were the defending State to respond in kind, capturing and inhumanely treating the aggressor State’s soldiers, that would amount to a belligerent reprisal. Fortunately, international law categorically prohibits belligerent reprisals against prisoners of war. Even the United States accepts that much.

In 1977, the United States signed Additional Protocol I to the Geneva Conventions, which categorically prohibits reprisals against civilians, objects indispensable to their survival, and their natural environment. But the United States never ratified Protocol I. In 1987, the U.S. State Department’s Legal Adviser listed the prohibition of such reprisals as one reason not to ratify Protocol I. In 2016, the U.S. Defense Department’s Law of War Manual indicated that the United States still takes the position that reprisals against civilians, indispensable objects, and the natural environment are permitted by customary international law. If an adversary attacks civilians, indispensable objects, or the natural environment, the United States reserves the right to do the same.

In August 2019, the International Law Commission adopted a set of draft principles (including commentaries) on the protection of the environment in relation to armed conflicts. Draft principle 16 simply says that “[a]ttacks against the natural environment by way of reprisals are prohibited.” The commentaries report that members of the Commission debated whether or not draft principle 16 codifies an existing rule of customary international law binding on all States. Rather than settle the question, the commentaries conclude that “the inclusion of this draft principle can be seen as promoting the progressive development of international law, which is one of the mandates of the Commission.” Simply put, if customary international law doesn’t already prohibit such reprisals, then it is heading in that direction and States should finish the job.

Due to the COVID-19 pandemic, the deadline for States to submit comments on the topic has been extended to the end of June 2021. The Biden administration should support draft principle 16. It should take the opportunity to clearly state that it will refrain from reprisals against civilians, objects indispensable to their survival, and the natural environment “out of a sense of legal obligation … and expects all other nations to [refrain from such reprisals] as well,” adapting the language of previous U.S. statements accepting rules of customary international law.

In taking such a position, would the Biden administration identify customary law, or develop it? It doesn’t matter. States are both subjects and co-authors of the law. Where customary law is settled, States have a legal obligation to follow it. Where customary law is unsettled, States have a moral obligation to settle it in the morally best way. No single State can settle the law for all, but each State should do its part and encourage others to do the rest.

Where does customary international law stand today? In 1970, the United Nations General Assembly unanimously affirmed that civilians should not be the object of reprisals (108 in favor, with eight abstentions). To date, 174 States have ratified Protocol I, which prohibits reprisals against civilians, indispensable objects, and the natural environment. None have asserted the legal right to take such reprisals in armed conflicts to which Protocol I does not apply.

On the other hand, the United Kingdom entered a reservation to Protocol I’s provisions prohibiting reprisals, and still claims the right to resort to such reprisals under customary international law. Egypt, France, Germany, and Italy made rather ambiguous declarations that they would respond to attacks against civilians “with all means admissible under international law.” In any event, all four of these States later affirmed the prohibition of reprisals:

In 1992, Italy’s law of armed conflict manual instructed that reprisals against civilians, objects indispensable to their survival, and the natural environment are specifically prohibited in all circumstances. An earlier passage says that reprisals cannot consist in acts of war directed against the civilian population “except in cases of absolute necessity.” But an intervening passage makes clear that reprisals may never violate a specific prohibition.

In 1995, Egypt submitted written comments to the International Court of Justice stating that “[t]he provisions of the [Geneva] Conventions and the [Additional] Protocols carrying this prohibition of reprisals against protected persons and objects are considered declaratory of customary law.”

In 2012, France’s law of armed conflict manual instructed that reprisals are permitted only against military objectives, and prohibited against protected persons, objects indispensable to their survival, and the natural environment.

In 2013, Germany’s law of armed conflict manual instructed that the law of armed conflict prohibits reprisals against civilians, objects indispensable to their survival, and the natural environment. In its 2019 statement to the ILC, Germany “appreciate[d]” that draft principle 16 “recogniz[es]” that reprisals against the natural environment are prohibited.

Two notes: First, I will spare readers a deep dive into horrors of the Iran-Iraq war of the 1980s, which other scholars have found cast more shadow than light on these questions. Second, the Department of Defense Law of War Manual cites and quotes at length from each of these States’ reservations to Protocol I to support the U.S. view. The Manual never mentions their more recent statements to the contrary. Yet another reason for the Biden administration to review and revise its position.

In my view, customary international law prohibits such reprisals, over the opposition of the United States and the United Kingdom. It is possible that persistent objectors to an emerging customary rule are neither bound by that rule nor protected by it. But two persistent objectors cannot prevent such a rule from emerging, and both binding and protecting the overwhelming majority of States that accept it. The Biden administration should drop its objection, encourage the United Kingdom to do the same, and accept the same rule that binds everyone else.

Suppose I’m wrong. The moral responsibility of the remaining States to drop their opposition to the prohibition and join the rest of the world would only increase. In 2005, the International Committee of the Red thought the lawfulness of such reprisals was unsettled due to the contrary practice of “a limited number of States, some of which is also ambiguous.” In 2021, the practice of France and Germany doesn’t seem particularly ambiguous. And, in my view, the practice of Egypt and Italy wasn’t particularly ambiguous even in 2005. But it doesn’t matter. The United States shouldn’t wait for others to further clarify their positions. It should take its own.

It wouldn’t take a particularly clever lawyer to push back against all of this. They could say that General Assembly resolutions are words, not deeds. They could say that treaty prohibitions can logically coexist alongside customary permissions. They could say that military manuals don’t always express State legal positions in all their complexity. They could note that Egypt, France, Germany, and Italy have not withdrawn their reservations to Protocol I. We expect lawyers to make these kinds of arguments for clients who are subjects of the law. But, as mentioned, States are also co-authors of the law. And these kinds of arguments would simply mask a dereliction of moral responsibility for the development of the law.

Reprisals against civilians are obviously morally wrong. Civilians are human beings. They have a basic moral right not be intentionally injured or killed, including as a means of changing the behavior of their State or some organized armed group. Civilians cannot lose this basic moral right due to someone else’s wrongdoing. Civilians are not the property of their States. They are persons with rights of their own. Reprisals against civilians are wrong for the same reasons that terror attacks and collective punishment are wrong, and that is what such reprisals are.

Reprisals against objects indispensable to the survival of the civilian population are reprisals against civilians in a flimsy disguise. Such reprisals are intended to change the adversary’s behavior by leaving civilians to suffer and die without food or water, gas for heat or electricity for medical care, as the case may be. Such reprisals use the civilians that they foreseeably harm, taking advantage of their vulnerability to achieve a further end, making such reprisals morally equivalent to direct attacks on civilians.

Reprisals against the natural environment are reprisals against civilians in all realistic cases. The legal protection of the natural environment includes, at its core, a prohibition on the use of methods or means of warfare which are intended or may be expected to cause widespread, long-term and severe damage to the natural environment and thereby to prejudice the health or survival of the population. Reprisals which contravene that core prohibition are intended to change the adversary’s behavior by prejudicing the health or survival of the population, using the civilians that they foreseeably harm. Perhaps one could imagine a reprisal against the natural environment that is likely to change an adversary’s behavior without harming civilians. I wouldn’t bother. We should develop the law of armed conflict with realistic cases in mind, not imaginary ones involving adversaries that violate the law of armed conflict but love nature for its own sake. Best to renounce all reprisals against the natural environment and be done with it.

In the past, the United States claimed that reprisals against civilians, indispensable objects, and the natural environment constitute “a significant deterrent that protects civilians and war victims on all sides of a conflict.” There’s no reason to take that claim seriously. As the Defense Department notes, there are plenty of instrumental reasons not to engage in reprisals, including the risk of counter-reprisal. The United States accepts that reprisals against sick and wounded fighters, prisoners of war, interned civilians, and cultural property violate its treaty obligations. So do reprisals against civilians using landmines. If we can do without such “deterrents,” we can do without a few more. Almost every other State in the world thinks it can defend itself without resorting to reprisals against civilians, indispensable objects, and the natural environment. There’s no reason for the United States to think otherwise.

Finally, the U.S. position is not that reprisals against civilians may be lawful in a supreme emergency to deter the adversary from killing thousands or millions of civilians. On the U.S. view, reprisals must be announced in advance, proportionate to prior violations, and undertaken as a last resort to deter future violations. But reprisals need not respond to or aim to prevent widespread or systematic violations of exceptional gravity. The United States considers reprisals “extreme measures of coercion,” but does not restrict their use to extreme circumstances. The logic of reprisals is symmetrical and collective. Tit for tat, their civilians for ours. That logic cannot be reconciled with the moral rights of individual civilians.

Conclusion

The Biden administration should renounce reprisals against civilians, objects indispensable to their survival, and their natural environment. The International Law Commission’s current work on the protection of the natural environment in armed conflict provides one opportunity to do so. In closing, I’ll add another.

The International Law Commission is also inviting States to comment on its draft articles on peremptory norms of general international law (jus cogens). A non-exhaustive list of peremptory norms, annexed to the draft articles, includes “basic rules of international humanitarian law.” The United States has previously questioned which rules of international humanitarian law the Commission considers “basic” and therefore peremptory. In its next comments to the Commission, the United States could take the position that the prohibitions on attacking civilians, indispensable objects, and the natural environment are peremptory norms, from which no derogation is permitted and breach of which is wrongful in all circumstances—including by way of reprisal. I think it should. But one step at a time.

Image: A displaced Syrian girl looks on at a camp created by Turkey’s Humanitarian Relief Foundation (IHH) in Kafr Lusin village on the border with Turkey in Syria’s northwestern province of Idlib on March 10, 2020.  (Photo by OZAN KOSE/AFP via Getty Images)