Ending Wars: The Law of War’s Latest Source of Stress

by , | Nov 12, 2020

Original_Geneva_Conventions. Ending Wars


The nineteenth anniversary of 9/11 offered a telling reminder of the problem of “forever wars.” In the United States, few Americans under the age of thirty can remember when the country was not involved in military operations in multiple countries and against multiple adversaries.

Concerns about such “never-ending wars” have centered on calls for Congress to reassert its rightful role in decisions to use force and on debates over the authority to detain, the meaning of membership in various armed groups, and effective strategies to contain future acts of violence.

These are critical issues, to be sure. However, perpetual conflict is also steadily increasing pressures on the law of war. These pressures result from an expectation that the law of war can or should be something for which it is neither designed nor equipped: a tool to bring ongoing conflict to an end.

Combining conflicts that have no obvious endpoint with the opportunistic use of legal authorities and frameworks has placed the law of war in the spotlight in ways that present significant risks. Three primary factors are at work here: limited legal rules to help mark the end of conflict; factual and strategic challenges in identifying the end to contemporary conflicts; and the emasculation of traditional tools ordinarily used to push for an end to conflict. As a consequence, the law of war has become a final hope to respond to perpetual war—by making such conflict more palatable through strict constraints on military action or, alternatively, by bolstering response authorities outside of conflict. This new “mission” is the law of war’s latest source of stress.

Key Factors Pushing on the Law of War

Identifying the End of Conflict: Limits of the Law

First, the law naturally arises in any conversation about the end of conflict. As a legal matter, it is axiomatic that the rules and thresholds signaling the start of armed conflict ensure clarity and predictability in the implementation of the law of war. Identifying the end of conflict—and thus the end of the law of war’s application (with a few exceptions regarding prisoners of war and other detainees)—is equally important. However, the law is sparse at best.

For international armed conflict, the Geneva Conventions reference the end of conflict with phrases such as “cessation of active hostilities” and “general close of military operations,” which the drafters understood to mean “when the last shot has been fired.” The classic means of ending an international armed conflict is a peace treaty, but such conflicts can also end through mutual consent, armistice, capitulation, surrender, or even a unilateral declaration.

In contrast, the end of non-international armed conflict is much murkier. Common Article 3 offers no guidance regarding the end of non-international armed conflict. Additional Protocol II references the end of conflict with respect to protections for persons detained due to the conflict but does not provide any rules or other guidance for identifying the end of conflict. Possible theories for identifying the end of non-international armed conflict include the State’s defeat of the non-State armed group; factual indicators such as “the mere fact that one of the Parties ceases to exist” or a “lasting cessation of armed confrontations without real risk of resumption”; or a “reverse engineering” of the Tadić test of intensity and organization for identifying the start of non-international armed conflict.

In sum, the law of war simply tells us that it no longer applies after a conflict is over and offers scant guidance for identifying that moment of transition—but includes no rules about whether parties to a conflict are required to end the conflict or how the conflict ought to end.

Factual and Strategic Uncertainty: When is a Conflict Over?

Second, a number of contemporary conflicts appear likely to continue for decades with little, if any, consensus regarding what “the end” actually looks like. The question of when a conflict with an armed group ends is extraordinarily challenging both as a matter of fact and strategy. General Petraeus’s quip “tell me how this ends” at the start of the 2003 conflict in Iraq presciently foretold the lingering uncertainty: Does the “end of conflict” refer to the end of United States or other foreign State participation in the counterinsurgency, to the end of the underlying local conflict itself, or perhaps to the end of a broader struggle against multifarious terrorist threats?

As Seth Jones explained during the inaugural workshop of the End of War Project, ending foreign participation is one issue; bringing the local conflict to an end is an entirely different matter. The latter rests on the specific goals and contestations of the local parties, while the former is determined by the foreign State’s assessment of the costs and benefits of continuing the engagement. However, if the foreign State disengages but the underlying conflict continues, the possibility of rejoining the conflict always remains in the absence of a durable peace.

This uncertainty becomes significantly more problematic in light of the U.S. combination of elastic, open-ended domestic legal authorities and extensive capabilities to strike anywhere around the globe. In effect, rather than actually end participation in a conflict with any finality, the United States has the opportunity and incentive—and legal authority—to re-engage whenever politically or strategically expedient.

In addition, in conflicts with terrorist groups, concepts of victory and defeat are amorphous and potentially only fleeting at best. Terrorist groups morph, splinter, and reconfigure, such that determining if, let alone when, they have been defeated in accordance with any notion of decisive victory is exceedingly difficult. In essence, a State may be engaged in a conflict where no one can effectively identify what victory would look like. In past conflicts, an opposing side’s unwillingness or inability to continue fighting might have signaled a decisive victory. Today, however, a group’s disengagement from fighting may merely reflect a deliberate strategic choice to lie low until the environment for launching attacks improves. In the same vein, spectacular attacks may be a counterintuitive sign that a terrorist group is significantly weakened or even in existential danger. When a lack of overt attacks no longer signals the enemy is in decline and major attacks can mean the group actually is much weaker, identifying the end of conflict based on an adversary’s actions can be extremely difficult.

Weakness of Traditional Tools Driving Conflict Termination

The third factor is that many of the tools one ordinarily would expect to do the work of ending conflict are emasculated or unavailable. For example, the open-ended and elastic 2001 Authorization for the Use of Military Force has undermined domestic law options for Congress to impose an end to the conflicts or even prevent new operations. Similarly, negotiation is unlikely to be desirable or effective in conflicts with terrorist groups.

Domestic political pressure will often be a powerful tool, but here too, it has little teeth. Although calls to bring U.S. troops home from Iraq, Afghanistan, or Syria, for example, have figured in some recent election campaigns, the American public’s general disconnect from contemporary U.S. military operations has drastically diminished, if not eliminated, the possibility that domestic political pressure will drive efforts to end these conflicts.

The nature of the enemy in these contemporary conflicts also makes it difficult to push for an end to a conflict by attacking the legitimacy of the operation. States fighting against terrorist groups that attack civilians and brutalize communities, like ISIS or al Qaeda, have little trouble asserting the legitimacy of their operations.

Finally, even strategic considerations can play a role here in sidelining traditional tools. Managing a terrorist threat—that is, treating it as a threat to contain rather than an existential threat—is often the appropriate course of action from a strategic standpoint. As a result, even when the engagement between the State and the terrorist group meets the threshold for armed conflict (where defeat is ordinarily the core strategic objective), the State actually may not seek to completely defeat or eliminate the group for strategic and policy reasons. The result: an armed conflict that simply persists because the appropriate strategy actually serves to perpetuate it.

The New Stress: Asking Too Much of the Law of War

Perpetual conflict and a toolbox bereft of effective tools for ending it has thrust the law of war into a jack-of-all-trades role as the solution to these challenges. The law of war is being asked to achieve goals that only remotely relate to its core tasks of regulating the conduct of hostilities and protecting persons during armed conflict. The consequences of these added burdens can be highly problematic.

In particular, the lack of other effective means of ending conflicts has shone a spotlight on international law as a last hope for encouraging, or even mandating, an end to an ongoing conflict. However, the legal regime designed to end or limit war—the jus ad bellum—focuses on regulating and limiting the start of conflicts, relying on prevention as the primary tool to limit the spread and hazards of war in general. Once a given conflict has begun, even the jus ad bellum offers few firm constraints on the extent of the use of force. We are left only with the law of war, thus creating an incentive to transform the law of war beyond a regulatory and protective framework and entrust it with a new mission of ending ongoing conflict.  However, apart from the law’s simple tools for marking the end of conflict, it is a significant leap to suggest that the law of war obligates parties to bring a conflict to an end.

Risk of Different Rules for Different Conflicts  

A first danger is that the law of war’s objective fact-based analysis for the existence of armed conflict—which applies to the end as well as the start of conflict—opens the door for parties to create enough facts on the ground to keep a conflict going indefinitely. Indeed, such a result is entirely plausible. Given the law of war’s authority to use lethal force as a first resort against legitimate targets and detain enemy personnel without charge until the end of the conflict, such self-selecting timetables for conflict inherently present significant dangers. Although the law of war may enable and even exacerbate this problem, looking to it for the solution by applying different thresholds for the end of conflict is deeply problematic. The resulting uncertainty, unpredictability, and differentiated application undermine the law’s effectiveness.

Risks of Using the Law to Make Conflict More Acceptable

A second effect of never-ending conflict is that the law of war is essentially being asked to make conflict more palatable by constraining the parameters for lawful action. A perpetual conflict is arguably easier to accept and justify if the levels of violence, death, and destruction resemble those more commonly associated with aggressive security measures than common perceptions of war. In essence, if the law of war is on the job to make war a lot less violent and deadly, then “it’s okay” if the war goes on for a very long time.

The law of war does indeed have a core purpose of minimizing suffering during war, but it is not designed to eliminate suffering altogether: the law accepts incidental harm to civilians, for example, and destruction of property based on military necessity. To ask the law of war to legitimize never-ending conflicts by sanitizing them, in effect, is to leave the law ill-equipped to function effectively in high-intensity and peer-on-peer conflicts when the policy constraints of counterinsurgency and counterterrorism operations no longer play a role.

Risk of Relying on the Law of War Outside of Armed Conflict

Finally, perpetual conflict can alternatively pose the opposite risk to the law of war by relying on it to assuage concerns about actions taken outside of armed conflict. One conceivable solution to never-ending conflicts with non-State armed groups is to find more robust authorities for the use of force outside of conflict, thus removing the need to maintain a state of armed conflict in order to benefit from the permissive authorities it provides.

However, although human rights law imposes important constraints on any use of force, it is not designed for and does not offer any specific rules for how to use force: identification of targets, means and methods, or minimizing incidental harm. Many have thus argued that the use of force in self-defense outside of armed conflict—so-called “naked self-defense”—is regulated by the law of war principles of distinction, proportionality, and precautions. Under such a theory, harm to civilians from an operation outside of armed conflict would be assessed based on the law of war principle of proportionality, even though there is no armed conflict to trigger the application of the law of war. Although neither the law of war, the jus ad bellum, nor human rights law supports this approach, the effect is to create the impression of a protective legal framework while still allowing for the significantly more robust and permissive authorities under the law of war.

The argument, in essence, is thus: if threats outside of conflict can be met with force regulated by the law of war—rather than the significantly more restrictive law enforcement paradigm—then the law has once again saved us from the dangers of perpetual conflict. This time, however, the law of war comes to the rescue by allowing peacetime security responses to function a lot more like wartime responses without the legal and political hurdles of accepting and justifying the existence of armed conflict.

Let the Law of War be the Law of War

Never-ending war already puts the law of war under enormous stress. The law’s core business lies in regulating the conduct of hostilities and limiting harm to civilians, not in bringing an end to a specific conflict or to end war more generally.

It may be no surprise that the law of war is seen as a potential savior—after all, it contains hundreds of treaty provisions and customary law rules setting forth specific obligations and methodologies for conduct during war. It is thus seemingly ripe for reliance in tackling any challenge relating to war. But asking the law of war to facilitate the use of varied rules to suit political objectives, limit the intensity of war, lessen concerns about prolonged conflicts, or enable robust solutions outside of armed conflict has real consequences for the application, interpretation, and development of the law.

The law of war is a legal regime for the extra-ordinary; only the exigency of armed conflict triggers the application of the law of war. If conflict becomes perpetual, so does the law of war; if conflict is no longer extra-ordinary, neither is the law of war. And herein lies the ultimate danger—the loss of the law of war as a common language and touchstone across all types of conflict. Rather than a delicate balance of military and humanitarian imperatives, of the permissive and the protective, the law will be found in the eye of the beholder—a form of “law of war à la carte” where one’s perspective and goals will be the sole arbiter of the law.

The law of war protects the vulnerable during armed conflict, from civilians trapped in the midst of hostilities, to wounded on the battlefield, to persons detained by the adversary until the end of the conflict. Asking it to also end war may simply be more than it can take.


Professor Laurie R. Blank and Dr. Daphné Richemond-Barak are co-founders and co-directors of the End of War Project. The Project hosted its inaugural workshop was in September 2019 at the International Institute for Counter-Terrorism’s Annual Summit, and is currently presenting its Fall 2020 Global Dialogue (see here and here). They welcome feedback as well as opportunities for future collaboration. 


Professor Laurie Blank is a Clinical Professor of Law, the Director of the Center for International and Comparative Law, and the Director of the International Humanitarian Law Clinic at Emory University School of Law.

Dr. Daphné Richemond-Barak is an Assistant Professor at the Lauder School of Government, Diplomacy and Strategy, IDC Herzliya, Senior Researcher at the International Institute for Counter-Terrorism and Adjunct Scholar at the Modern War Institute at West Point.