The Oxford Handbook of the Use of Force in International Law (edited by the highly distinguished Cambridge University international law scholar Marc Weller) labors under two handicaps before ever reaching the book's content. First, at over $200 in hardback on Amazon, only readers with easy access to a decent law library will be able even to lay eyes on the volume (and the Kindle edition is $190). Second, at 1279 pages (and weighing in at 4.2 pounds), even readers who can lay (both) hands on a copy are likely to be daunted by the sheer quantity of articles and contributors. Not many readers would likely to be interested in more than a handful of articles on particular topics.
This is unfortunate because, though it has taken His Serenity, the Book Review Editor, nearly a year to at least skim every article in the volume (while reading and re-reading certain ones with a great deal of attention), he has concluded that the book contains a great deal of important material - including articles that will bear re-reading years down the road in order to understand the winding evolution of international law on the use of force over several decades. Indeed, the greatest single strength of the volume is precisely the one that readers seeking only one or a few articles will miss - the remarkable coherence of the volume as a whole. It ranges across a vast terrain of controversies in the international law of the use of force, both jus in bello and jus ad bellum, and offers articles with sometimes sharply differing viewpoints that, taken together, give the attentive reader a grasp of the many controversies - and, not least, wide gulfs between fundamental viewpoints about the nature of law in this area.
A great deal of credit goes to Marc Weller for, among other things, managing to herd the professorial cats (so to speak) to address their topics in a way that permits the reader to see the connections among them. His introductory essay (as well as his preface) also does a great deal to situate otherwise disparate articles in relation to one another. The organization of the volume is logical, starting with the relationship of law and war, and next winding through issues of jus ad bellum - with a lot of attention to the vexed jus ad bellum issues of armed conflict and non-state actors, the beginning and end of non-international armed conflict, the "legal geography" of armed conflict, and self defence, among others. The book then turns to "emerging" topics in the jus in bello such as drone warfare, weapons law, cyberwarfare, and private military contractors. It has a quite good set of articles on international collective security and the role of the UN and Security Council.
At risking of offending large numbers of eminent scholars by mentioning a couple of articles and ignoring the rest (bear in mind there are 57 separate chapter/articles), I was quite struck by the debate between Tuft University's Michael J. Glennon, "The Limitations of Traditional Rules and Institutions Relating to the Use of Force," on the one hand, and James Crawford and Rowan Nicholson's "The Continuing Relevance of Established Rules and Institutions Relating to the Use of Force," on the other. Taken together, the two articles seemed to exemplify a deep divide, between something I've sometimes described as "pragmatic" and "formalist" views of international law of the use of force. Indeed, if there is any single methodological cleavage that is found across all the different articles and topics, I would say this is it.
This gulf seems to me to explain in at least some important part the striking differences in legal analysis, understandings of doctrine, notions of authoritative sources, and conception of what makes "law" in this field found in section III of the book - a collection of chapters mostly addressing the highly contested, "boundary" issues of jus ad bellum today. Jorg Kammerhofer's "The Resilience of the Restrictive Rules on Self-Defence" exemplifies one way of approaching these questions, while Lawfare's own Ashley Deeks' article in the same section, "Taming the Doctrine of Pre-Emption," illustrates another. Setting Deeks' article in relation to Kammerhofer's (and several others in this section) from a methodological perspective, "The Resilience of the Restrictive Rules on Self-Defence" takes a much stronger formalist stance than I would venture to say is the norm of international law interpretation of many US government lawyers at State and elsewhere.
"Taming the Doctrine of Pre-Emption," for its part, carries some range of pragmatic considerations into the law itself. Deeks' argument is very far from being some wild, extra-legal warrant for governments to do what they like in the matter of preemption. On the contrary, it's an effort to cabin it within genuinely legal principles that could plausibly be shared by very different state parties. Hers is a moderately "pragmatic" understanding of the law, but nonetheless it remains an argument and viewpoint "internal" to international law itself - not at all something looking to external "emergencies" or "necessity" to sweep the substance of the law aside.
Of course there is room to dissent from the view I've suggested here - viz., that this "pragmatic" view of international law is genuinely an "internal" account of law. It's quite possible simply to say that all this talk of "pragmatism" is just another way of saying "your legal answer comes from 'outside' the law, taken on its own terms, but you don't want to admit it." Likewise there is room to object and declare that, with respect to the doctrine of preemption specifically (rather than all of international law of the use of force), Deeks' way of cabining the doctrine of preemption just is asserting legal conclusions reached on extra-legal criteria. In that case, the formalist-pragmatist divide appears, in methodological terms, to be ships passing in the night. Meaning, at that point, one might reasonably conclude that these two understandings of the nature of international law don't share enough in common to permit debate on particular questions of legal interpretation.
But another kind of methodological divide also seems to me at play, even if only implicitly, across many chapters in the book. This is the divide over the nature, evidence and authority of state practice - with respect to international law in general and custom in particular. The topic of state practice seems to lurk beneath the surface of many of the articles in section III (dealing with the boundaries of the jus ad bellum) even when it is not explicit. As a question of authority in asserting the content of customary international law, no one disputes that state practice is an essential element in ascertaining customary law. But then serious divides arise as to what that means. For example, should "state practice" take into account (or, anyway, how much account should it take, with respect to) what ministries of defense might, and often do, put in their military manuals and written documents on the laws of war. Does it matter if the states in question will likely never have occasion to be at war, so as to draw upon those legal provisions and have to interpret and abide by them, in actual circumstances of war and battle? Or should state practice give greater weight to what states with armies engaged in the conduct of hostilities in the field actually do in the belief that it is lawful?
A number of years ago, our own John Bellinger (then State Department Legal Adviser) sent a letter (jointly authored with the DoD GC) to the International Committee of the Red Cross, challenging a number of positions reached in its Customary International Humanitarian Law Study. A particularly important point of US government objection was the ICRC mass citation of the world's military manuals in support of the ICRC's positions, over the facts of actual state practice in actual armed conflict by states that actually engage in armed conflict. (I incline, it will surprise no one to hear, to the views expressed in that joint letter.) It's a methodological divide across the chapters of the Handbook, it seems to me, because so few of them address what, in one circumstance or another, states actually have done as a matter of historical record.
Well. That leaves 53 more chapters in the book to discuss, and this Brief Review can't be called "brief" any more. It's not feasible for any review, however, to do more than sample a few of the questions that the many chapters in this Handbook call to mind. But I never anticipated reading more than a bare handful of pages in this book - enough for a one paragraph mention at Lawfare. To my own surprise, I found myself returning to the volume, slowly, over months, until I had finally read the whole (damn) thing.