Reviving Opinio Juris and Law of Armed Conflict Pluralism

It is by now hackneyed routine. A U.S. government attorney or legal policymaker invited to appear at a law of armed conflict (LOAC) conference prefaces her remarks with a pro forma reminder that nothing she will say necessarily reflects the views of her department, her agency, or the U.S. government. The audience understands, perhaps having been subject to the same obligation in a past professional life or having been conditioned to accept the disclaimer as the price of a glimpse into government practice. Still, the value of the official’s appearance and the event feels somehow compromised.

Admittedly, government representatives’ presentations and public writings still offer highly relevant and informed perspectives on LOAC. Yet the absence of official government opinions unequivocally stated inevitably robs the conversation of a degree of magnitude, significance, and clarity. Is it any wonder that lawyers exhaustively deconstruct the comments of a State Department Legal Advisor when he is willing to speak disclaimer-free? Conditioned to a wet blanket of disclaimers, the LOAC community craves official views.

The stifling effect of official disclaimers is not limited to academic panels and conferences. State disclaimers, legal equivocation, and worse, silence extend to the general dialogue of LOAC. The result is an increasingly unbalanced LOAC colloquy, deprived of the pluralistic balance of State and non-State, military and humanitarian, European and American perspectives that would enrich and balance the development and direction of LOAC.

It has not always been so. Recent LOAC history reveals episodes of rough proportionality between State opinio juris and non-State expressions of law. In the immediate aftermath of the Second World War, non-State actors produced important and influential interpretations of LOAC such as Jean Pictet’s 1949 Geneva Convention Commentaries. Scholars, non-governmental groups, and international organizations produced persuasive, even fairly authoritative constructions of LOAC and treaty proposals. Jurists also made important contributions to LOAC through reasoned judgments and briefs in war crimes trials.

The United States kept pace for a time. U.S.-convened and supported criminal prosecutions of war crimes were instrumental to the development and efficacy of LOAC. The U.S. also produced comprehensive LOAC analyses and guidance for its armed forces such as the influential 1956 U.S. Army Field Manual on the Law of Land Warfare. In 1996, despite enjoying relative peace, U.S. attention to and concern for the development of LOAC even extended to submitting an amicus curiae brief in the seminal Tadić case at the International Criminal Tribunal for Former Yugoslavia. The result of these efforts was a more pluralistic, balanced, and active LOAC dialogue – a rough proportionality between State and non-State input on this critical and central facet of international law.

Today’s international LOAC dialogue appears in stark contrast to the vibrant and pluralistic exchanges of the past. To be sure, non-State LOAC commentary continues to thrive. Legal journals routinely feature challenging LOAC articles, library shelves groan under ever-expanding collections of impressive LOAC doctoral dissertations, and war crimes tribunal judgments run to 1300 pages or more. All the while, humanitarian organizations publish extraordinary and imposing multi-volume LOAC studies, with more in development. And “groups of experts” publish private manuals on a growing number of LOAC topics, available here, here, and here.

Meanwhile, the U.S. guns of LOAC opinio juris have fallen nearly silent. The 1956 Army Field Manual remains in service, still the only comprehensive and inter-service law-of-war manual. Interagency bickering and turf battles stymie decades-long efforts to publish crucial legal and operational guidance. Long-promised updates appear to be in the works, as they have been for decades. However, the fact remains that despite the addition of nearly a dozen major LOAC treaties since publication and despite well over fifty years of regularly occurring armed conflict, U.S. military lawyers deploy with the law-of-war manual of their grandfathers.

U.S. inactivity and silence is not limited to national military legal doctrine. International criminal convictions grounded in interpretations directly at odds with U.S. understandings of targeting rules provoke virtual silence, leaving only former officers to respond in their private capacities. The ICRC’s now authoritative, 3000-page customary IHL study inspires not a competing product, but rather a 29-page “cross-section[al]” review, focused primarily on general international law methodology. Drastic reinterpretations of fundamental legal guidance for detainee status determinations and armed conflict classification by the Department of Justice and White House are not published as open contributions to LOAC doctrine and dialogue. They are buried in classified legal opinions, unavailable until leaked, even to military lawyers responsible for developing and teaching U.S. LOAC doctrine. Emerging forms of warfare and a broadening operational spectrum provoke “law by analogy” or merely policy statements rather than definitive legal analysis. And meanwhile the ongoing proliferation of private LOAC manuals inspires no substantial, official response.

It is no wonder the U.S. Supreme Court mistakes Pictet’s Commentary as “the official commentary to the [Geneva] Conventions” (see n.48), despite the authors’ disclaimer to the contrary. It is no wonder international war crimes tribunals cite humanitarian organizations’ reports and studies rather than States’ opinio juris. The U.S. government and many other specifically-affected States offer them little choice.

It is necessary to remember that States and their agents enjoy unique relevance in the formation and interpretation of international law and LOAC. As the primary authors and subjects of LOAC, States should actively shape its content and direction, through both direct means, such as treaty formation and state practice, and indirect means, such as positions proffered in litigation, legal publications, public statements, and diplomatic communications.

Even as scholars challenge sovereign-centric understandings of international law, near universal respect endures for the special role of sovereigns in the formation of international law. To coopt and modify a common observation with respect to Originalism in constitutional interpretation, “Everyone is a Sovereigntist sometimes.” That is, what distinguishes dyed-in-the-wool international law Sovereigntists from non-Sovereigntists is probably not acceptance of the legitimacy of State input but rather attitudes toward non-State actors’ international legal contributions.

Few international lawyers contest that resort to State expressions of opinio juris constitutes a principled method of interpretation. Disagreements seem instead to concern the effect that absence of State opinio juris has on an international norm. And while there is surely value in the balanced pluralism that results from having both State and non-State contributions to LOAC, State input has always been singularly significant. State opinio juris remains the critical bellwether for the degree of consensus, acceptance, and therefore effectiveness and legitimacy of any international legal rule.

In addition to formal authority, States possess unique competency, facility with, and access to the inputs of LOAC. While many grasp the harsh consequences of armed conflict, few outside the ambit of States’ defense agencies and armed forces fully appreciate armed conflict’s operational challenges, demands, and limitations, so essential to striking the delicate LOAC balance between military necessity and humanity.

Not unlike the government speaker’s conference disclaimer, the effect of States’ retreat from LOAC dialogue is an impoverishment of dialogue. LOAC discussions, debates, and deliberations, both descriptive and normative, founder in the absence of authoritative State opinio juris. Whatever one’s opinion of the substantive quality or correctness of State opinio juris, State legal opinions provide indispensable control samples for meaningful analyses and critiques. The efforts of legal practitioners and scholars, commanders and humanitarian workers, advocates and judges all suffer when States do not make clear and frequently update their views on the content, interpretation, and future direction of LOAC.

Parity of input, especially in quantitative terms, is surely too much to demand and surely not necessary given the special status of State opinio juris. However, States’ legal agencies and agents should be equipped, organized, and empowered to participate actively in the interpretation and development of LOAC. States, and specially-affected States in particular, should make active responses to emerging LOAC scholarship, investigations and jurisprudence a regular facet of their opinio juris. Reinvigorating opinio juris would do far more than satisfy international law sovereigntists. It would go a long way toward reestablishing the pluralistic LOAC dialogue that formerly tested, updated, and enriched the balance between military necessity and humanity.

This post surely leaves a number of associated issues unaddressed and assumptions unexplained. For instance, the causes of and motives behind U.S. LOAC opinio juris atrophy are undoubtedly complex and not fully understood. Is desire to maintain operational and diplomatic flexibility to blame? Does retreat from opinio juris reflect a deliberate and considered evaluation of the costs and benefits of silence? Are institutional competence, bureaucratic friction, or organizational culture to blame? Or is ascendancy of a general international law skepticism the cause? Whatever the true causes or motives of the U.S. retreat to the sidelines of LOAC, more active U.S. participation would be a meaningful step toward restoring a truly pluralistic LOAC. 

About the Author(s)

Sean Watts

Professor at Creighton University Law School, Reserve Instructor in the Department of Law at the United States Military Academy at West Point, Senior Fellow at the NATO Cooperative Cyber Defence Centre of Excellence, Served as an Active-Duty Army Officer in both the Armor and Judge Advocate General’s Corps (1992-2007), Current Army Reservist