International Judicial Monitor
Published by the American Society of International Law and the International Judicial Academy
May 2006, Volume 1, Issue 2

In Review:
New Publications on International and Comparative Law

War and the Law of Nations: A General History, by Stephen C. Neff, Cambridge University Press 2005

History is an enlightening and wonderful way to learn about any subject. International law is no exception.

Although the origins of international law go back far in history, into antiquity, modern international law, which began in Europe, originated out of the issues of war and peace. The seminal work of the "father" of modern international law, 15th Century Dutch jurist Hugo Grotius, was titled De Jure Belli ac Pacis, On the Law of War and Peace. If modern international law began with issues of war and peace, arguably so did international law generally, as Stephen Neff so ably demonstrates in his new book.

Stephen Neff, Reader in Public International Law at the University of Edinburgh, is a well-versed international legal historian (two previous books on international legal history). In his new work, he does not start with Hugo Grotius, he starts with the Greeks, and also somewhat surprisingly, with China. Neff writes:

The real beginning of our story came when people began to think about war in terms of a general rationalistic framework that could be applied to any specific decision about war....By about the middle of the first millennium BC, the Confucian tradition in China had devised a set of systematic ideas about government that was impressive not merely for the generality of its scope but also for the prominent role played in it by moral ideas.  For the first time in history, a conception of war was integrated into a cohesive general structure of social, political and moral theory. War was seen as a means of last resort, to counteract antisocial conduct and reinforce the norms which integrated the society into a harmonious whole.

Neff, after his interesting introduction, divides his narrative into four historical periods: (1) from "misty beginnings" up to about the year 1600; (2) from 1600 to 1815; (3) the 19th Century; and (4) the 20th Century, beginning particularly with the time after World War I, to the late 20th Century and the first few years of the 21st Century. Although there is in the book significant discussion and commentary with examples about each period, Neff focuses most of his attention on the "European intellectual adventure" known as "natural law," which had its origins in the writing of the Greek stoic philosophers and Roman jurists and reached its zenith in the European Renaissance and the post-Renaissance period of the 16th and 17th Centuries.

One of Neff’s surprising observations, stated early in his story and one that will undoubtedly appeal to persons of "pacifist temperament," is that war, the main feature of which is its collective nature, "would...appear not – or at least not quite - to be a universal feature of the human condition." In support of this observation, Neff identifies certain known societies that have "lacked any idea or practice of collective combat" as opposed to "interpersonal violence."

Neff, in his beginning chapters reviewing the first period, discusses thoroughly the nature and character of war, identifying its characteristics and how it was practiced in various places at various times by various societies, to delineate it distinctly from other human activities. He then turns to his discussion of the attitudes about war in medieval Christian Europe, examining thoroughly the doctrine that rose to prominence then – the just war theory.

He attributes to Grotius and his aforementioned treatise on the law of war and peace and the subsequent distinction made between the law of nature and the law of nations as a "momentous" change – "perhaps the single greatest intellectual leap that has ever occurred in the history of international law." The reason, he says is the "emancipation of statecraft in general, including international law, from the principles of interpersonal morality, which had been so pronounced a feature of natural law thought." This new law of nations, described by Grotius, "was seen as a purely human creation, a product of the free will of man, again contrasting with the older law of nature."

The 19th Century, Neff argues, was a time when war "reached its pinnacle of legal prestige." This development was because international lawyers viewed war as an "accepted and routine means of conducting everyday international business." Laissez-faire in war as in economics was the rule of the day. That all came to an end, however, with the First World War and all of its attendant horrors and the slaughter of millions on both sides of that conflict. The world could no longer afford to view war as a routine practice of statecraft in the face of its capability of wiping out the human race.

The result, states Neff, in discussing the fourth and final period of his analysis, was a return to just war theories. The ascendant idea of this period is that the normal state of international relations is one of peace, with war permitted only as an exceptional act requiring "affirmative justification." This was the rationale behind those sections of the Charter of the United Nations that permit war in only two instances: self–defense and when authorized by the Security Council. He also identified one movement that has had an important effect on attitudes about war, the "humanitarian revolution," that has marked a "fundamental shift" in the nature and purpose of rules governing the prosecution of armed conflict. The shift, he notes, was brought about by the view that war is not an inevitable clash of national interests, "but rather as a human tragedy."

Part of Neff’s conclusion at the end of the book is worth repeating, in that it sets forth the issue with which public international lawyers and political and government leaders must grapple with for the remainder of this century, an important issue in light of the current war in Iraq:

Is it better that war be sharply cut off in a legal sense from peace, and ruled by principles that are, as it were, tailor-made for it? Or is it preferable to dissolve all barriers between war and peace to the greatest extent possible, to live in a single, undifferentiated legal and moral world at all times? In other words, it may be wondered whether war should be a distinct legal institution, as in the nineteenth century; or whether it should be seen as an aberration in a monolithic state of peace. The moralist and the idealist will instinctively incline in favour of the second of these choices, and against the idea of a special legal institution of war. The reason is easily seen. War as a legal institution smacks too strongly of a matter-of-fact acceptance of the most monstrous social evil known to the human race. It looks too much like a craven surrender of morality to the harsh demands of Realpolitik, too much like a legal seal of approval of large-scale psychopathy.

It is difficult to do justice to all of the thorough and interesting commentary, analyses, and examples that Stephen Neff provides in this discussion of the history of war and its relation to law. His arguments and commentary are very convincing, his style clear, straightforward and readable. This book should be required reading for all students of international law, and should be high on the reading list of all others who are interested in international law generally, including academics, legal advisors to governments, and practitioners of public international law.

Stephen Neff has done a great service to public international law by writing what is perhaps the only modern and certainly the most comprehensive analysis of the history of the law of war in the context of international law. It should become and belong among the "classics" of international legal literature.

By James G. Apple, Co-Editor, International Judicial Monitor and President, International Judicial Academy

« Back to the first page

ASIl & International Judicial AcademyInternational Judicial Monitor
© 2006 – The American Society of International Law and International Judicial Academy.

Editors: James G. Apple, Katherine Brantingham and Andrew Solomon.
IJM welcomes comments, suggestions, and submissions.
Please contact the IJM editors at