International Law and the Ongoing Armed Conflict in Ukraine

By Brian Cox

February 24, 2022, is a date which will live in infamy. Like the poignant opening to Franklin D. Roosevelt’s legendary speech the day after the “unprovoked and dastardly attack” on Pearl Harbor some eighty years earlier, this is the date the United States became involved in an armed conflict that caught the population by surprise. Unlike the formal beginning of the United States’ participation in the second global armed conflict of the twentieth century, however, America was not attacked directly on this occasion and no state of war has been declared between the United States and a belligerent party.

This latter date of infamy, of course, represents the day Russia commenced a full-scale invasion of neighboring Ukraine. For many observers the world over, the current conflict in Ukraine stirred a profound sense of shock and disbelief. The scourge of warfare has by no means been completely eradicated since the close of hostilities at the conclusion of the Second World War, but international relations are supposed to be different now in the era since universal ratification of the Charter of the United Nations.

The “new international law” enshrined in the Charter—to borrow from Judge Alejandro Alvarez’s description in an individual entry written for the first major opinion published by the fledgling International Court of Justice in May 1948—is supposed to represent a “law of social independence” among the United Nations. The members of this “universal international society,” according to Judge Alvarez’s ideal, are “concerned with the maintenance of peace and the development of cooperation among all States of the world.” If a dispute arises, as Alvarez writes a year later in a separate opinion for the decision in the Corfu Channel case, states are now required as a matter of law to “have recourse, not to force but to the Security Council or to the International Court of Justice” unless an exception to the new norm applies. Here, observes Judge Alvarez, “we see clearly the difference between the old and the new international law.”

Yet, here we are. At the time of this writing, Ukrainian security forces are engaged in a bloody counteroffensive struggling to regain control of vast stretches of territory that have been occupied by Russian forces since the current invasion began. President Volodymyr Zelenskyy is helping to orchestrate a valiant domestic resistance while urgently imploring political leaders across the globe for assistance. The message from Ukraine is particularly blunt when directed to European capitals: help us now, or you will be next.

Although the implications of the conflict in Ukraine on the global political order are difficult to fully fathom since hostilities remain ongoing with no peaceful resolution currently in sight, there is no question that the continued viability of the “new international law” is in grave peril. While it is clear that the international legal order that materialized in the wake of the Second World War will never be quite the same, the full extent of the change to come is not yet fully in focus. Even as the conflict currently rages on, though, it is not too early to reflect on how this catastrophe happened and where we may go from here.

When the full invasion began last spring semester, I was teaching a seminar at Cornell Law School focused on exploring the relationship between international law and U.S. foreign policy. The ensuing armed conflict emerged as an unexpected focal point of the semester, though with a concerted effort to adequately engage with this topic while not allowing it to fully consume our attention. My ongoing dissertation as a J.S.D. candidate is centered on clarifying the connections between armed conflict and human rights in theory and practice, so of course the current conflict in Ukraine remains one focal point of my studies. And I began my present scholarly pursuits after retiring from a twenty-two-year career as a combat arms soldier and officer, and for the last seven years as a judge advocate, in the U.S. Army.

Against this backdrop of experience and professional pursuits, I have studied and reflected extensively on the conditions that led to the full invasion of Ukraine and on how the ongoing conflict may transform the “new international law” that emerged from San Francisco as the Charter of the United Nations was negotiated and adopted in 1945. Like most other worthwhile scholarly pursuits, this is a subject that could fill multiple volumes if afforded the necessary time, resources, and commitment. Although that extent of study may well develop as a professional pursuit in the future, this essay constitutes an opportunity to present an overview of what I believe may be some of the most salient topics to consider involving the impact of the armed conflict in Ukraine on the study and practice of international law going forward.

One of the most important topics implicated by the full invasion of Ukraine is whether the ensuing armed conflict constitutes a “war” in the traditional sense and, if not, what are the implications of a negative conclusion. This is a subject that has very little consequence on the conduct of hostilities, as the body of law known as the law of armed conflict applies whether or not it is deemed to be a “war” in the traditional sense. However, this designation is the under appreciated starting point for engaging with other significant matters in both international law and U.S. foreign policy.

While historical tomes are filled with reflections on what exactly constitutes a “war” and what does not, the description presented in Lassa Oppenheim’s 1906 treatise on international law is widely cited still today. According to Oppenheim, “War is a contention between two or more States through their armed forces, for the purpose of overpowering each other and imposing such conditions of peace as the victor pleases.” Although it is popular in current discourse to refer to a “war on terror” or protracted American military involvements as “forever wars,” the United States has not been engaged in a war in the traditional sense since the close of the Second World War.

In the context of international relations, whether the conflict in Ukraine qualifies for designation as a war in the traditional sense implicates the law of neutrality. This body of law involving the legal relationship between belligerent states and neutral states may seem antiquated today, but I posit this is because wars in the traditional sense are the exception rather than the rule in the era of the U.N. Charter . . . so far. If the conflict in Ukraine were to qualify as a war in the traditional sense, providing arms and other military supplies to Ukraine from the United States and other nations would violate obligations of neutral states and risk the suppliers becoming directly involved in the war as belligerents.

Although the implications of the conflict in Ukraine on
the global political order are difficult to fully fathom since
hostilities remain ongoing with no peaceful resolution
currently, in sight, there is no question that the continued viability of the “new international law” is in grave peril.

Brian Cox

Of course, all armed conflicts produce tragedy and loss, regardless of whether designation as a “war” applies. Although it is a fact-dependent inquiry and reasonable perspectives can certainly differ, I tend to assess that the conflict in Ukraine does not qualify as a war in the traditional sense. The specific factors I consider in this determination are necessarily beyond the scope of the present essay. However, if Russia’s “special military operation” in Ukraine does not qualify as a war, the seemingly anachronistic law of neutrality does not apply and conduct such as supplying weapons, training Ukrainian security forces, and sharing intelligence does not risk the United States being designated as a belligerent in the conflict.

As a matter of domestic law, designation of the conflict implicates the constitutional balance of power between the executive and legislative branches. Opinions written by the Department of Justice Office of Legal Council dating back at least to 1994 indicate that “the anticipated nature, scope, and duration of the planned deployment” of U.S. troops must be considered in the fact-specific determination regarding whether a proposed or actual military engagement qualifies as “‘war’ in the constitutional sense.” If it does, Congress must exercise its constitutional authority to declare war as specified in Clause 11 of Article I, Section 8; if it does not, the involvement is almost certainly the exclusive purview of the president pursuant to Article II, Sections 1 and 2. If President Joe Biden had contemplated positioning U.S. troops in Ukraine with a view to deterring Russian aggression prior to the invasion, or if he now considers getting American troops directly involved in the conflict in response to future developments such as the use of chemical or nuclear weapons by Russia, whether the engagement would qualify as “war in the constitutional sense” will be of central importance in determining whether Congress must be involved in the decision.

Another vital, but under appreciated issue is clarifying the precise connections between armed conflict and human rights. While Ukrainian officials and various transnational entities are actively investigating thousands of allegations that Russian forces have committed horrific war crimes during the course of hostilities, there is also no shortage of assertions that the same or similar conduct likewise constitutes gross human rights violations. However, the applicability of human rights law in the first instance remains a contentious matter.

My preferred solution to this unsettled issue is to apply the sovereign/belligerent conceptual framework developed by Jens Ohlin in “Acting as a Sovereign versus Acting as a Belligerent,” a chapter he wrote in the book Theoretical Boundaries of Armed Conflict and Human Rights (CUP, 2016). Pursuant to this model, human rights law would not apply to Russian forces because Russia is acting as a belligerent—and not a sovereign—in the conflict. This would not foreclose the prospect that Russian forces have committed war crimes on a potentially unfathomable scale, but this conduct would not qualify as gross human rights violations since human rights law would not apply in the first instance.

While this is merely a small sampling of the sweeping implications of the ongoing armed conflict in Ukraine on the theory and practice of international law, as well as the domestic implementation of the same, there is no doubt that the conflict has the very real potential to reshape existing notions of the “new international law” described by Judge Alejandro Alvarez a few short years after the conclusion of the Second World War. Existing principles and rules of international law may well bring solutions to the seemingly intractable problems that have materialized already and that will continue to emerge. However, it is appropriate to temper this admittedly optimistic view with a cautionary note in closing.

The ideal described by Judge Alvarez in 1948 of a “universal international society” wherein members of the then-fledgling United Nations are “concerned with the maintenance of peace and the development of co-operation among all States of the world” has never fully materialized. As the unipolarism that emerged following the conclusion of the Cold War three decades ago gives way to an increasingly multipolaristic world, the “new international law” that rose from the ashes of the Second World War may well prove increasingly incapable of averting global conflict. The promise and optimism related to the capacity of international law to prevent or solve global challenges must be considered along with the limitations inherent therein.

Overreliance on the perceived protection provided by international law can foster a false sense of security that is ultimately shattered by the horrors of armed conflict. Absent this misplaced overconfidence in the capabilities of international law, decisions may be taken on the road to war that serve to deescalate tensions and defuse an emerging conflict before it erupts into open hostilities. Though it is still too early to tell for sure, I believe miscalculations produced by an over-reliance on the ability of international law to prevent full-scale armed conflict— if not an actual war—will emerge as a central legacy of the ongoing conflict in Ukraine.