by Stephen C. Neff. Cambridge, U.K.: Cambridge University Press, 2005. 456pp. Cloth £65.00/$120.00. ISBN: 9780521662055. Paper. £23.99/$45.00. ISBN: 9780521729628. eBook format. $85.00. ISBN: 9780511124082.

Reviewed by Walter J. Kendall, III, Professor of Law, John Marshall Law School, Chicago, Illinois. Email: 7kendall [at] jmls.edu.


This prize winning book has just been reissued in a paper edition. It is a study of the concept of war, specifically the legal concept and its implications for going to war, for how wars are fought, and how they are ended – jus ad bello, in bello, and post bello.

Stephen Neff, a Reader in Public International Law at Edinburgh argues that it was not until war was no longer thought of as natural or inevitable that a legal concept could form. It first had to be thought of as a matter of conscious human choice (p.9). It could then be seen as a distinct feature of life, subject to norms, rules, even laws as are all other features of social life. He identifies war as a subset of normal human conflict characterized as a collective public armed yet rule-bound undertaking, targeted at foreign peoples.

Each of the underlined words is important for comprehending the development and evolution of the legal understanding of “war” as a distinct social event or experience. These words serve as a template for the rest of the book. They make it possible to distinguish criminal behavior, duels, riots, terrorism, and rebellion for instance, from war itself. These deconstructions of the larger concept of armed conflict in turn facilitate the development of regulatory rules and laws. Without such a distinction any rule developed would be so general, with so many exceptions, as to be no rule at all. Marking war off from peace by the use of some form of declaration of war, has prehistoric roots, although the particular methods vary greatly over time (p.26). Gentili is credited with being the first post-medieval legal theorist to discuss the methods of both initiating and terminating war (pp.103, 115).

After tracing these distinctions back to early mythology, both western and eastern, Neff fast forwards to “one of the most momentous ideas in human history . . . that war could and should be employed . . . for the subduing of evil and the promotion of good – that it should be an instrument of law, rather than of greed or ambition” (p.29). This notion of a “just war” not only recognizes war as intentional, it also assumes the normal condition of inter-societal affairs is peace. “The conception that peace was the natural condition of the world would seem to have been first articulated in China, in the Confucian tradition” (p.31). The stoics later developed a similar view which they elaborated to include universal norms of behavior (p.32).

Christianity for several centuries seemed to consider war as impermissible. The [*1065] only alternative to bad government and obedience to laws requiring “sinful” behavior was martyrdom. Constantinianism and the threat presented by the barbarian invasions provided a frame into which Ambrose and Augustine could paint both Pauline obedience to Caesar, and the duty to protect the vulnerable, resulting in a militarized Christianity.

This transformation in thought makes Chapter 2, “Loving Enemies and Hating Sin,” most interesting. Its discussion of “the conception of war that underlay and pervaded (the medieval Christian just-war doctrine) and which flowed from it” (p.54) resonates as it does because the issues raised are so modern. In fact Neff ends his study with an extended and detailed discussion of the post-World War II period, labeled as “just war reborn” (p.277).

The daunting, perhaps impossible risk of formulating humane and yet efficient laws of war is illustrated by the paradoxical admonition of Paul which begins this chapter “Let us do evil, that good may come” (p.39). When necessity was the single great principle applicable to the conduct of war, not surprisingly, moderation was not the norm (p.73). Despite codes of chivalry, slavery, torture, destruction and confiscation of property, crusades, and the conquest of native peoples were the norm from Augustine to Aquinas, even to Vitoria in the 16th century.

One bridging thinker, who Neff overlooks and whose work had a significant impact on the laws of war, is Bartolome de Las Casas. Las Casas penned the first coherent and compelling defense of the rights of indigenous people, in effect formulating rules or norms to regulate the conduct of the Spanish conquerors in the Americas (Gutierrez 1993).

Neff sets the evolution of the legal conceptualization of war in four long but unequal historic periods: to 1600; 1600-1815; 1815-1919; 1919- ____. Neff himself recognizes that adopting a different periodization could change the meaning of events, by in effect creating similarities and differences, even trends that are not there so to speak. The German language has a term that describes the significance or effect of periodization: verfremdungseffekt, which can be translated in this context as to make the familiar seem strange or vice versa. Be that as it may be, Neff’s periodization permits him to focus on the following question: “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 (o)r 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?” (p.397). He does not answer his own question. Rather he offers his book as a series of period pieces providing insight into the challenges and dilemmas of trying to cabin war in legal categories.

Rules in war have always existed. Certainly by the time of the Jewish Bible and Sun Tzu’s Art of War there is a strong sense that wisdom and knowledge rather than strength and brute force won wars (p.21). However, it was not until the 1863 Lieber Code that there was a generally accepted detailed, even seminal, codification and exposition of the laws of war (p.186). [*1066]

In the period from Vienna to Versailles, there was an intense debate between three competing schools of legal thought about war as such. The mainstream view running from Grotius to Vattel tried to combine the medieval, natural law just war understanding with a new more consensual voluntary law of nations (pp.95-96). Such a dual vision of externally imposed and voluntarily accepted norms was inherently unstable. It is frankly amazing that it preserved peace and limited war when it broke out as well as it did for almost 200 years.

Hobbes challenged the central tenet of this mainstream view, that peace was the norm. He famously described life in the state of nature as nasty, brutish and short. Pufendorf’s thought on the other hand shows more or less clearly the influence of the other school of thought about war (p.137). This was a contractual or dueling view which accepted peace as the norm; but it asserted that conduct during war was determined by agreement between the warring parties, rather than for any natural law.

“Nowhere was the distinction between the three schools of legal thought about war so sharply etched as in the area of neutrality” (p.151). Logically, the just war aspects of the mainstream view left no room for neutrality. Just wars were struggles between good and evil; neutrality was impossible, one was either with or against the Good. By contraast, both the Hobbesian and duelist views recognized that third parties are not directly involved in the war. However, they had different views of the rights of neutrals. Hobbes argued that belligerents had a right to protect themselves from “neutral” acts that aided the enemy. Thus, neutral ships could be boarded and their weapons and supplies confiscated. The duelist or contractual school resolved such “conflicts” in the neutrals’ favor; belligerents had no rights to interfere with neutrals in the exercise of their normal activities.

When the mainstream view did come to recognize neutrality, it sought a middle ground. In the 18th century it was generally accepted that enemy goods being shipped on neutral vessels were, except for weapons, free from capture and confiscation (“free ships make free goods”) (p.154).

Neff discusses the 19th century transformation of war into an instrument of state policy in Chapter 5 under the title, “Collisions of Naked Interest.” He argues that “jus ad bellum . . . shriveled into virtual nothingness” during this period (pp.163-164). At the same time, jus in bellum was revitalized and developed across a range of issues. This era (1815-1919) was the period in which the Red Cross was founded and the first Geneva Convention and early Hague Conferences occurred; and also as mentioned earlier, the Lieber Code. Neff asserts that these rules of war had a “sporting ethos” at their core (p.189) which necessarily meant that war was of a limited nature. The sense of limitation was reinforced by the Martens clause (p.210). The belief at the time was that these rules would prevent any further “total” wars such as the Napoleonic Wars (Bell 2008).

Equally significant is the fact that these legal understandings of war opened the door to “interventions” into the disputes of other states and even into their [*1067] internal matters – with all the attendant risks of abuse and dangers to peace (pp.219-229).

Finally, Neff discusses the very long and open-ended period, beginning in 1919 with the Treaty of Versailles and the League of Nations. Neff argues that, although the League of Nations and especially the Pact of Paris (the Kellogg-Briard Pact) were attempts to restore the much earlier just-war era, legal thought stayed anchored in the 19th century. Obviously neither was able to succeed in the 20th century.

Neff presents in capsule form some of the efforts and thinking of the international legal establishment that are otherwise left out of or rushed past in all but the most specialized studies of the period. These include efforts to understand acts that do not quite fit under the understanding of war but involve armed conflict: acts such as self-defense (pp.303-307); the “new neutrality,” a policy of quarantine or boycott (pp.307-311); and FDR’s lend-lease efforts at “non-belligerency” (pp.311-312).

After the breakdown of the League of Nations order, if it ever existed, and World War II, the United Nations was established. The Charter sought to end war as such. It allowed for self-defense, but only until the U.N. itself or regional organizations, acting as law-enforcement authorities, could intervene. As is well known, for a variety of reasons the basic structure failed to the extent there were dozens of small hot wars in the following 50+ years. Yet perhaps it did succeed. Doesn’t the U.N. deserve some credit for the fact that the big hot war we all feared, remained cold? Certainly Nuremberg and its progeny have had salutary impacts as sources of law and preservers of memory each of which are necessary, if not sufficient, conditions for peace and justice.

Yet obviously that is not the end of the story. There is the uneasy sense that the notion of a “state of war” with all its attendant rights of belligerents, killing, destroying and capturing co-belligerents, people and property, is still a legal category (pp.347-356). And as Neff entitles his penultimate chapter, there are “New Fields of Battle” (p.357), specifically, civil disturbances and terrorism.

Neff says the law has recognized four or five categories of civil disturbance: sporadic acts of violence; “ordinary internal armed conflict;” situations where the rebels have established some control; national liberation struggles; and perhaps something akin to interstate war (p.375).

And then there is terrorism. While there is a history going back hundreds if not thousands of years of random acts of violence, what makes terrorism different is that the motivation is neither riches nor even power. Rather, the violence is motivated by ideology, often shared by a group. Otherwise it remains a simple crime, however despicable. Since it is more than a mere crime, but certainly different from war as historically understood, this form of armed conflict has challenged traditional thinking about international law, human rights, and humanitarian law.

Neff’s template with which he began (collective, public, armed, rule-bound, and foreign) has served well. Certainly [*1068] he has offered valuable insights into the function of declarations of war, into why states go to war, and into the concepts of neutrality, reprisal, and self-defense. However, Neff gives too little attention to treaties and the significance of the end of a war as the other half of what marks war off from peace. There are two brief mentions (pp.117-119, 210-214), but the significance of jus post bello and the question “does peace lead to war?” (Hughes and Seligmann 2002) receives less attention than one could reasonably have expected. Nevertheless, by taking us behind the rules one can see how the legal notions he develops in depth were different in each of the periods he constructs.

While Neff says in his introduction that we will see that “war has moulded law at least as surely as law has moulded war” (p.2), frankly he fails to deliver on this promise. There are some cause and effect statements throughout, but no real causal analysis of the conceptual transformation he so carefully describes. Be that as it may be, Neff provides a much deeper analysis of the logic of ideas about war than either Kennedy in his short essay (Kennedy 2006) or Bobbitt in his encyclopedic tome (Bobbitt 2002). This book is highly recommended to those interested in either the history of ideas, or international law.


Bobbitt, Philip. 2002. THE SHIELD OF ACHILLES: WAR, PEACE, AND THE COURSE OF HISTORY. New York: Alfred Knopf.

Gutierrez, Gustav. 1993. LAS CASAS: IN SEARCH OF THE POOR OF JESUS CHRIST. Maryknoll, NY: Orbis Books.

Hughes, Matthew, and Matthew Seligmann. 2002. DOES PEACE LEAD TO WAR? PEACE SETTLEMENTS AND CONFLICT IN THE MODERN AGE. Phoenix Mill, UK: Sutton Publishing.

Kennedy, David. 2006. OF WAR AND LAW. Princeton, NJ: Princeton University Press.

© Copyright 2008 by the author, Walter J. Kendall, III.