Washington Lawyer September/October 2026
By Jeremy Conrad
In 2026 at least 20 active wars are being fought across four continents, with tens of thousands of lives lost in hostilities. Among the many exchanges of fire in today's armed conflicts are competing accusations that one side, or both, have committed war crimes. Aggrieved nations and third-party critics cite improper targets or tactics and the deployment of inhumane weapons.
Determining the merits of these accusations can be difficult, given that the agreements forming the basis for laws of war were drafted at least 70 years ago. Changes in technology and society since then have resulted in battlefields that are radically different today.
Michael P. Scharf, law professor at Case Western Reserve University School of Law and president of the American Branch of the International Law Association, says the world has seen technology advance in ways not foreseen since the last major updates to the Geneva Conventions.
"While the general principles of discrimination, necessity, and proportionality generally apply, AI targeting, use of autonomous drones, and nonkinetic cyberattacks are not specifically covered. New rules will close gaps and make compliance more likely," says Scharf, who established Case Western's War Crimes Research Office.
Rules of Engagement
In the West, laws of war have their roots in the ancient Roman religious and legal tradition of jus belli. The Latin terminology inspired the 20th-century terms jus ad bellum (justifications for entering a war) and jus in bello (the conduct of parties engaged in combat). These concepts were enshrined in modern law by the drafting of domestic and international codes and agreements that share some common foundations.
The Lieber Code, commissioned by the U.S. Army during the Civil War and produced by Prussian American jurist, professor, and political philosopher Francis Lieber, is considered the first codification of the laws of war. Among its provisions, the Lieber Code addressed the principle of humanity, the distinction between combatants and civilians, prisoner of war status, retaliation, whether armed force is justified by military necessity, and permissible methods and means of warfare.
The Lieber Code influenced many of the subsequent agreements, such as the Hague Conventions of 1899 and 1907 and the Geneva Conventions of 1949 — the principal basis for laws of war and universally adopted by nations to regulate armed conflict. While the United States signed the Geneva Conventions' Additional Protocols of 1977, it declined to ratify them, primarily over objections to Additional Protocol I. According to a collection of declassified documents posted in 2023 by the National Security Archive, the Pentagon believed that Protocol I — strengthening the protection of victims in international armed conflicts — favored terrorists.
However, the United States has generally considered itself bound to many of the Additional Protocols as customary international law. The U.S. Department of Defense's Law of War Manual, released in 2015, reflects the general principles referenced by Scharf: military necessity, distinction (discrimination), and proportionality. Distinction refers to the limitation of combat to military personnel, material, and facilities. This principle acknowledges that some civilian loss of life or property may occur in the pursuit of legitimate military goals.
Proportionality refers to the balancing of military advantage against the unintended, but unfortunately anticipated, civilian harm that may occur. Going further, even if an attack does not violate the principles of distinction and proportionality, an attacker must exercise precaution to spare the civilian population. For example, a weapons cache located on a school playground could be targeted at night, when children are not present.
Michael W. Meier, adjunct professor at Georgetown University Law Center, spent a significant part of his career on matters relating to the laws of armed conflict. For nearly 23 years he served as the law of war subject matter expert for the U.S. Army Judge Advocate General's Corps, as an attorney-advisor with the Office of the Legal Advisor for Political-Military Affairs at the U.S. Department of State, and as an Army judge advocate.
Meier asserts that the existing laws of war are pliable enough to accommodate emerging circumstances, provided that nations analyze proposed actions and equipment using the standard principles as guidance. "I think that the rules as they exist are flexible enough to handle even the situations that we have now," Meier says.
He acknowledges that the rules are "under stress currently," citing the development of autonomous weapons. "So, just as we found with chemical weapons, biological weapons, land mines, and cluster munitions, there may be a need to regulate specific types of systems, but I don't see that we need a wholesale revision of the laws of war," Meier says. "The standard principles ... of distinction, proportionality, and discrimination still apply and are being applied in armed conflict today."
Old Norms, Complex Wars
A middle path is suggested by Allen S. Weiner, senior lecturer in law and director of the Stanford Program in International and Comparative Law at Stanford Law School. Weiner, who is also director of the Stanford Center on International Conflict and Negotiation, served as a career attorney in the Department of State, first as an attorney-advisor in the Office of the Legal Adviser and later as legal counselor at the U.S. Embassy in The Hague.
Weiner says that problems with applying existing laws of war to new weapons and tactics could be addressed with issue- or weapon-specific agreements and nonbinding commitments by nations. "I think there clearly would be areas in which additional treaty law would be beneficial. The problem is [that] these issues are deeply, deeply contested," he says.
Weiner notes, however, that these obstacles have not prevented nations from coming to agreements on the use of specific weapons in the period since the introduction of the Additional Protocols. "There's the Ottawa Convention [prohibiting] anti-personnel land mines, the Convention on Certain Conventional Weapons, a treaty on the prohibition of nuclear weapons that was adopted — although, of course, none of the countries that have nuclear weapons have become parties to that treaty — and the Chemical Weapons Convention, all adopted since 1977. So, there have been treaties making it impermissible to use particular classes of weapons in wartime," Weiner says.
"Although it would be good in principle to have a new treaty, I think the prospects of reaching agreement on such treaties are very, very remote," Weiner adds. "As a result, the international community has focused more on trying to reach shared understandings about how we should interpret and apply the rules that we have agreed on."
In general, Weiner says, nations have agreed that the principles of distinction, proportionality, and precaution are foundational tenets of international law. "Now, what we have to talk about is how we apply them to the use of an autonomous weapon," says Weiner. "At this point, I think the best that we can do is to have academics and groups of state experts collectively meet, write, and try to see if we can reach a consensus on international norms. I'm using the word 'norms' rather than 'laws' — norms that reflect widely accepted interpretations of how the law should apply to these new weapons."
Nonbinding understandings that establish norms might not be enforceable but, as a practical matter, compliance with international law is rarely rooted in external enforcement. Although instances of wrongdoing undoubtedly take place, Weiner says it can be a mistake to focus only on cases in which the law is violated. He cites the statement by Columbia Law School professor Louis Henkin that "almost all nations observe almost all principles of international law and almost all of their obligations almost all of the time."
Weiner believes that hedged optimism of this sort is grounded in the self-interest of states and other actors in conflicts. "A lot of the fundamental rules of [international humanitarian law] are rooted in the idea of reciprocity," Weiner says.
A state's immediate interests in a particular conflict may lead it to break international law — for example, by torturing detainees to obtain information or by justifying prohibited actions as necessary. However, Weiner argues that it is the role of attorneys and scholars to remind government officials to look beyond short-term gains and consider the long-term benefits of upholding a system of mutual rights and obligations that depends on continued compliance. "That's the tension that arises in international law all the time," Weiner says.
Definitions of Combatant
When it comes to participants in modern armed conflicts, a parallel conundrum exists regarding whether to draft new laws, reinterpret the existing ones, or enter into informal agreements. On their face, laws of war typically describe combatants and civilians, but there is a gray area of different actors falling between these two groups. The common groups — uniformed state armed forces — are recognized as "lawful combatants." Generally speaking, lawful combatants can be targeted without violating laws of war and, if captured, these groups are entitled to be treated as prisoners of war and given immunity from criminal prosecution for their acts as soldiers.
A second type of combatant includes forces such as Russia's Wagner Group: mercenaries that are effectively civilians participating in an armed conflict. These individuals may be classed as "unlawful combatants," troops that do not generally qualify for prisoner of war status and can be prosecuted for their criminal acts. Militias are commonly, but not always, associated with a state.
Next are armed groups not associated with a state, referred to as "unprivileged belligerents," which may include terrorist groups, drug cartels, and other independent armed forces involved in conflicts. Like unlawful combatants, unprivileged belligerents are not treated as prisoners of war or given immunity from prosecution. There is disagreement among nations regarding the treatment of both unlawful combatants and unprivileged belligerents, with some arguing that they are civilians under the current laws of war.
Finally, there are civilians — individuals not taking part in hostilities who are protected under the Geneva Conventions and Additional Protocols. However, this group includes a subcategory of civilians directly contributing to hostilities, such as those involved in arms production or provision of economic, political, and administrative support. Laws of war may classify civilians who directly contribute to hostilities by either their status (membership) or their conduct, according to Meier.
"Individuals that make bombs or direct troop movements are doing things that make them a part of the conflict," Meier says. "So, for the time that they are doing that, they would be targetable, but they still don't have combatant immunity."
The United States and the International Committee of the Red Cross (ICRC) have divergent views on this issue, according to Meier. "The ICRC only considers individuals targetable at the exact moment that they are performing these combatant functions. The United States considers an individual to be targetable once they have participated in hostilities until they take some sort of action to permanently stop their involvement," he explains.
Put another way, the United States would consider a bomb-maker targetable due to their status as an arms producer until they quit arms production altogether, while the ICRC would consider the same individual targetable only during the hours of the day in which they are engaged in the making of bombs.
In today's conflicts, where hacking and cyberwarfare are involved, determining the classification of a participant in hostilities has become even more complex. Even if the activity is proven to be directly related to a conflict, there is the additional problem of attribution — whether those participating in hostilities are doing so on behalf of a state.
Under today's laws of war, how might those actors be characterized? "I'm going to have to give you the lawyer answer: It really depends. Your intelligence officers, your operations, your lawyers are going to have to figure out who is the group, what are they doing, and how they can respond," Meier says.
Law Meets the Battlefield
Case Western's Scharf says that the existing laws of war are clear and that alternative approaches require changes in the law. "The Geneva Conventions expressly recognize two categories: combatants and civilians," says Scharf, who previously served as an advisor to the Department of State, including as a delegate to the United Nations Human Rights Commission.
However, neither the Geneva Conventions nor their Additional Protocols define what conduct amounts to direct participation in hostilities that "would justify the targeted killing or mistreatment of terrorists, pirates, and members of narco cartels," says Scharf.
In this instance, Weiner again sees the solution in informal and issue-specific agreements. "In a perfect world we would develop new treaties like the Additional Protocols reflecting state agreements on some of the key issues we are facing," he says. "But where we can't do that, we can try to reason by analogy when we face new situations or weapons systems, taking general principles from our settled rules of international conflict."
Reasoning by analogy is the methodology largely employed by states seeking to address the challenge of applying international humanitarian law to the types of conflicts that have become more prevalent since 9/11, according to Weiner. "What are the rules of asymmetric armed conflict, which is to say, wars between a state on one hand and a nonstate group on the other … civil wars within a country or transnational, noninternational conflicts like the war that the U.S. fought against Al-Qaeda or against the Islamic State? This approach gets us pretty far but doesn't get us all the way because we may not reach shared understandings about which interpretations we should use," he says.
In the interim, experts share their belief that laws of war have been generally successful in ensuring that conflicts are more humane and orderly than they would be otherwise. "Here at Stanford Law School, students take criminal law during their first year, and it turns out that the textbook is full of cases in which people broke the law. You might look at that and say that the law isn't working because all those crimes were committed," Weiner says. "In evaluating whether the law is working, we need to think about all of the cases in which states do comply with the law. We need to think of all the times the dog didn't bark."
D.C. Bar staff writer Jeremy Conrad is an attorney who has spent much of the past decade writing about the legal profession. Previously he practiced in immigration law and criminal defense.
