The Viability of the Law of Armed Conflict in the Age of Hybrid Warfare

It is increasingly common to hear the term “hybrid warfare” used to describe the complexities of the modern battlefield. When Russia uses a “combination of instruments, some military and some non-military, choreographed to surprise, confuse, and wear down” Ukraine, it is termed hybrid warfare. The term also refers to conflicts which are both international and non-international in character, such as the ongoing conflict in Syria. And overlapping conventional and asymmetric tactics in an armed conflict—as when Russia simultaneously conducted cyber-attacks during a conventional invasion of Georgia in 2008—also gets the hybrid warfare label. Or, as Professor Bobby Chesney recently wrote regarding U.S. operations in Somalia, hybrid warfare can include “a sophisticated approach that layers together a panoply of low-visibility (to the public both here and there) tools” to conduct counter-terrorism operations in failing states.

“Conflict complexity” and “hybrid warfare” are increasingly synonymous. So it is unsurprising that the topic of hybrid warfare arose during a recent workshop on “Complex Battlespaces: The Law of Armed Conflict and the Dynamics of Modern Warfare” hosted by the Lieber Institute for Law and Land Warfare—a new academic center nested within the United States Military Academy’s Department of Law. The workshop addressed a myriad of difficult international legal problems and, while no particular session focused exclusively on hybrid warfare, talks on classifying conflicts in fragmented states and the impact of urbanization on the regulation of warfare inevitably led to discussions on the topic.

Throughout these conversations it became apparent that hybrid warfare, used as a shorthand for all types of complications on the modern battlefield, is no longer considered unusual. Difficulty distinguishing civilians from combatants, the intermixing of direct and indirect approaches to warfighting, and ambiguity in conflict classification are all expected in the contemporary combat environment. It is also understood that states will counter this confusion by blending law enforcement, intelligence, and military actions into a single comprehensive governmental response. Today’s conflicts are therefore defined by the blurring of traditionally distinct lines and, as a result, hybrid warfare is no longer considered an anomaly but rather the norm.

But notably, the workshop participants—thought leaders in national security and law of armed conflict—all observed that the era of hybrid warfare has not resulted in significant changes to the law of armed conflict. Application of the law continues to depend on how a conflict is characterized. Individual status determinations are still required to understand the associated rights, duties, and responsibilities of those on the battlefield. A conflict participant’s conduct remains regulated by the general principles underlying the law. In other words, the dramatic differences in how war is fought in the contemporary battlespace has not altered the fundamental framework, structure, and triggers of the law of armed conflict.

But the natural follow-on question remains unanswered: should the law of armed conflict evolve along with modern warfare? The hybridization of warfare has, undoubtedly, strained the traditional law of armed conflict paradigm. For example, the law of armed conflict is rooted in the binary differentiation between international and non-international armed conflicts. Classifying a conflict as one or the other is the first step to determining the applicable law. Yet, today’s wars defy this either/or classification and are more likely to have characteristics of both types of conflicts.

This is one of many similar hybrid war issues which challenge the law of armed conflict’s regulatory effectiveness. Often, the uncertainty characterizing hybrid warfare is only eventually addressed through rigorous examination and creative application of the law. This may mean the law is theoretically functioning, but in practice it becomes less useful over time. As my colleague Professor Robert Barnsby and I previously wrote “the continued effectiveness and enforceability of the law of armed conflict is highly dependent on whether the expressed rules remain definitive, understood, and accepted in today’s complicated conflicts.” If only international legal scholars and the most experienced of practitioners understand how to apply the law of armed conflict in hybrid warfare, then the law is slipping towards irrelevance.

An irrelevant law of armed conflict has dangerous implications. The law of armed conflict “ensures that force is applied in warfare in a manner allowing for mission accomplishment while simultaneously taking appropriate humanitarian considerations into account.” While the law at times fails to maintain this equilibrium, resulting in disappointing outcomes, the alternative is unregulated warfare. War unchecked by the law has well-known and horrific results. It is therefore imperative that the primacy of the law of armed conflict remain unquestioned. And this primacy is dependent upon the law being easy to understand and easy to apply. Unfortunately, the opposite is proving true in the hybrid war age. Confidence in the law of armed conflict is undermined by a growing sense that it is incapable of handling the complexities of the modern battlefield. Perhaps it is time for some updates.