Book Reviews

A Necessary Discussion About International Law

By Ken Watkin
Tuesday, December 13, 2016, 11:00 AM

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A review of Jens David Ohlin and Larry May's Necessity in International Law (Oxford University Press, 2016).

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The post-9/11 security environment has placed international law under tremendous stress.  The requirement to react to transnational threats posed by non-State actors has forced the international legal community to consider how various bodies of law governing the use of force interact with one another.  Traditionally, legal frameworks such as the jus ad bellum (law governing the recourse to war), jus in bello (international humanitarian law-IHL), and international human rights law have been largely dealt with as discrete bodies of law. However, contemporary operations have raised new issues involving States acting in self-defense against “terrorists” who previously were viewed as criminals uniquely subject to a law enforcement response; and introduced questions regarding the use of force, including whether there is an obligation to consider capture rather than killing these protagonists.

Jens David Ohlin’s and Larry May’s book provides a timely and very important analysis of one of the foundational principles of these bodies of law: necessity. As the authors note, “[o]ne single word— ‘necessity’—hides a litany of deep and sometimes contested intuitions about the appropriateness of killing.”

This is not the first international law text to discuss the international law principle of necessity.  However, this impressive work provides a unique and fresh perspective. It analyzes the meaning of necessity not just in legal terms, but also deeply probes its moral and normative underpinnings. The 21st century dialogue about law and war has largely become “secularized”, and it is the grounding of this book in Just War based concepts of morality and philosophy that sets this work apart. The book’s return to the roots of the various bodies of law governing the use of force provides an invaluable place from which to deconstruct and rebuild many contemporary beliefs about how law regulates force.  As is noted, legal frameworks such as jus ad bellum and jus in bello share a common root in the “constraint on national conduct during warfare”. While the legal and philosophical domains have become estranged since the 19th century, the authors have identified the need to trace necessity’s “emergence from prior philosophical and legal material.”  It is a discussion that extends to military necessity as a license to use force, human rights law as necessity’s most constraining application, and necessity as a state of exception in international criminal law. 

The results of this in-depth analysis of necessity will not please all readers.  That likely will be the case for advocates who seek to broadly expand human rights notions of necessity into areas traditionally governed by the humanitarian law concept of “military necessity.” However, the authors equally question “whether our current reciprocity-based system of IHL is up to the task of regulating asymmetrical conflicts of today and tomorrow….”  Ultimately, this book takes a middle road between using necessity to justify exceptions from legitimate principles of morality and trying to “radically remake warfare into a glorified police action.”  The discussion points to the drawing of a line at a point situated between these two extremes. Professors Ohlin and May “propose a more moderate thesis that merely calls for less than lethal force when it is not necessary to use lethal force.” Yet the use of the modifier “mere” masks a deep and considered analysis of the factors at play. Importantly, this book is not simply a retrospective look at law and morality.  The analysis is ultimately applied to many of the most controversial issues facing the international legal community and security personnel in this century: the interface between humanitarian law and human rights law, a suggested obligation to disable rather than kill in warfare, a possible duty to capture prior to initiating a lethal strike, and to what degree soldier’s lives must be risked to save civilians.  The analysis in this book will force advocates of the various interpretations of these issues to pause and think about the philosophical bases of what for some have been long and deeply held beliefs.

Necessity has a ubiquitous nature that puts it at risk of being equated to Thomas Franck’s view of proportionality as being a concept which has “mostly eluded definition in any but the most general terms.” However, as Ohlin and May explain, necessity is a multifaceted principle with broad application in international law. Described as a cluster concept, it can be an exception to otherwise binding obligations, a license to act in certain ways, or a constraint that blocks certain activity because it is not “necessary.” A strength of this text is that the different contextual meanings and applications of necessity are explored in such detail.  This effort is greatly assisted by the clear roadmap provided by the authors in the introductory chapter, as well as at the start of each chapter. The chapters also contain succinct, but highly useful conclusions, which not only confirm the arguments made in the chapter but also help to well prepare the reader for the analysis that follows. 

The different contextual applications of the principle of necessity is demonstrated in the analysis of the jus ad bellum, including its use in the last resort and as a component of self-defense; in a jus in bello context regarding the principle of distinction, the Lieber Code’s foundational interpretation of “military necessity,” necessity’s interface with international human rights law, and how it is applied in international criminal law; and, finally, regarding the role necessity can play, primarily in contemporary asymmetric wars, in introducing a greater level of humanity into conflicts.  This is not a book suggesting wholesale amendments to treaties, or radical interpretations of the existing law. Rather, it champions an incremental and subtler rebalancing of international humanitarian law toward the principle of humanity (“which covers much of the same ground as human rights principles”).

Notably, there is a very useful analysis of “military necessity”. It is described as “a term of art in jus in bello with a particular conceptual meaning that diverges quite sharply from commonsensical understandings of the concept of necessity.”  At its core, military necessity serves as a licensing function of the law of war, with only an “incredibly weak” regulating role focused on “acts of vengeance, cruelty, and sadism.” The authors’ firm grounding of military necessity in Francis Lieber’s Civil War Code leads to the statement that “[w]hat separates murder from lawful belligerency is the collective nature of that conflict and the fact that the killing is performed in order to achieve the collective geopolitical aim of the war.” It is this collectivism that is viewed as limiting efforts to more broadly introduce the human rights law based concept of necessity. 

Human rights advocates might dispute an interpretation of military necessity that relies so heavily on the Lieber Code.  Indeed, it is jarring to think that despite all the social, technological and operational advances over the past 150 years contemporary views of military necessity might be locked into a 19th Century conception of the law.  Yet it is the authors’ very reliance on this interpretation that forces the reader to think deeply about whether war has fundamentally changed over time. This includes when the fight is against non-State actors. Importantly, contemplating the role human rights law might play in humanizing war requires consideration of its radically different conception of necessity. Human rights-based necessity was developed not in terms of “co-equal belligerents meeting each other,” but rather in “how a government treats its own citizens (and noncitizen subjects) internally.” It is the issue of whether the government is acting as a belligerent, or a sovereign (i.e. governing) that has made resolving use of force issues during counterinsurgency operations so challenging. Professors Ohlin and May present a detailed and thoughtful discussion concerning the difficulties of directly applying “human rights law in armed conflict, so that human rights law and IHL cross-fertilize each other, producing a humanizing effect….”

There has not been sufficient discussion about the degree to which human rights law should or can effectively regulate the violence associated with armed conflict.  This work presents an important starting place for any analysis about whether human rights law is up to the task being demanded of it by some in the international legal community. Can human rights law principles based on the “individual” adequately control the exceptional levels of violence associated with what is fundamentally a group activity: armed conflict? Would there be need to radically alter the human rights version of necessity for that body of law to do so? 

In this book, the interaction between these two bodies of law is explored in terms of various degrees of co-application, often as a form of “gap filling” particularly in respect of non-international armed conflict. However, rather than have a direct application of human rights law the authors point to an approach in which at “the level of moral theory, basic principles of human rights might affect how we understand IHL’s current balance between necessity and humanity….”  It is one that proposes soldiers not only be afforded the right to not suffer unnecessarily, but also that “in those, perhaps rare, circumstances where military objectives can be reasonably accomplished without lethal force,” they should be.

Not addressed is how a state should proceed in a case in which there is continuing operation of both human rights and humanitarian law (as was identified in the 2004 Wall Case), or in which there is no ability to apply one body of law to enrich the other or fill gaps. There is a simple choice by the State about which available body of law to apply. In that context, the question might also be asked whether belligerents are morally obligated to choose the human rights law-based approach if that body of law can effectively achieve the desired military objective.

The focus in the last part of the book is on asymmetric conflict. It offers an analysis that overall is realistic, although perhaps, at times, aspirational.  In terms of realism the authors refreshingly note that a frequently disputed concept in contemporary analysis, the “unwilling and unable” test, applied to justify State self-defense is not a new doctrine at all. It is “simply an application of the necessity requirement for the use of self-defense.” This is consistent with D.W. Bowett’s reference in his 1958 book, Self-Defense in International Law, that the unwillingness or inability of a State to protect the citizens of another State forms the legal basis for an intervention to defend nationals. In respect of the targeted killing debate, it is also noted that critics wrongly “focus on jus in bello necessity to the exclusion of jus ad bellum necessity.” As is pointed out, the real nature of these critics’ objection stems from a belief that the United States “is engaged in armed conflict that is not truly necessary.” In this regard, it might be added that this is consistent with the view that the “drone” debate about the “geography of war”, and the setting of high thresholds for the existence of a non-international armed conflict, seems almost intended to have a jus ad bellum effect.

The interaction between jus ad bellum and jus in bello also underpins one of the key recommendations of the book: the continuing application of the jus ad bellum during armed conflict, which the authors argue can result in a restraint on unnecessary killing. Such restraint would apply to retreating soldiers, on the grounds that when the requirement to resort to force has “evaporated,” the “continued use of force is unnecessary.”  Here, the book relies on a jus ex bello condition: “a moral requirement governing when a State must end an armed conflict.”  While not all international lawyers agree that jus ad bellum continues to operate once a significant armed conflict between States commences, there is a strong argument that it does for conflicts with non-State actors. Such discussion about the interaction between the various bodies of law governing the use of force is a strength of this book. 

There are two areas where the analysis presented in the book may overreach in championing theory over practical perspectives relating to the use of force.  The first is the reliance placed on the 2006 German Aviation Security Case regarding the shoot-down of hijacked aircraft. The analysis of that case is presented in support of the adoption of “a broadly Kantian constraint on the application of the defense of necessity.”  In that decision, the passenger’s inherent right to dignity was privileged to the point it cannot be violated “regardless of what happens next.” Unfortunately, the line of reasoning adopted by the German court appears significantly divorced from the reality that, during armed conflict, security personnel must regularly make the very value judgments the court refused to embark upon. Reliance on this decision may impact the broader acceptance of an otherwise well-presented theoretical argument. Secondly, the authors argue that it is not easy to show there is a principled reason to distinguish State from non-State actors in terms of waging a defensive or aggressive war, and the corresponding obligations of ad bellum necessity.  While an attractive theoretical argument, the strong resistance demonstrated by States towards granting any trappings of equivalency, and in effect legitimacy, towards insurgents or terrorists could ultimately limit the utility of this approach. 

This book should be required reading for anyone seeking to unravel what at times seem to have become intractable ideological debates about how the various bodies of law operate to control the use of force in contemporary conflict.  To date, too much of the discussion has occurred without addressing the substantive theoretical underpinnings of the law governing State self-defense, international humanitarian law, human rights law, and international criminal law.  Therefore, this work is a most welcome addition to the scholarship on “necessity”, and Professors Ohlin and May are to be commended for addressing these complex and challenging topics.