International lawyers have played a central role in shaping contemporary understandings of and responses to civil war, including through debates over whether external actors can intervene in civil wars, what rules govern the resort to force, how neutral actors might continue trading with warring parties, and when investors and property owners are owed compensation for any losses suffered during the conflict. While such questions have concerned international lawyers for almost two centuries, they have again become pressing issues given the role of third states and other actors in initiating, supporting, financing, directing, policing, and profiting from civil and proxy wars in the Middle East and North Africa, Eastern Europe, and Latin America. In addition, the novelty of the U.S. claim to be engaged in a global form of “non-international armed conflict” or civil war has posed significant challenges to traditional conceptions of international law. More broadly, the increased militarization of civil life in the twenty-first century has challenged fundamental distinctions upon which international law has depended, including between civil and international, domestic and foreign, and war and peace.

In that context, the arrival of a book by the Harvard historian David Armitage offering an intellectual history of the idea of civil war could not be more welcome. The work of Armitage is well known to international lawyers. For many years, Armitage was one of the few historians who took an interest in international law—a fact that is now hard to believe given the recent proliferation of work by historians exploring aspects of the international legal past. He was at the forefront of the “international turn in intellectual history,”Footnote ¹ publishing influential work on the ideologies of British imperialism and the foundations of modern international thought, and co-editing a volume curating the writings of C.H. Alexandrowicz.Footnote ² In addition, Armitage is a historian who has remained comfortable with writing expansive, longue durée histories,Footnote ³ and his scholarship has been more compatible with the style and sensibility of legal argument than that of historians committed to undertaking tighter forms of temporal contextualization.Footnote ⁴

Both Armitage's interest in international law and his ease with historical study spanning centuries are on display in his consequential intellectual history of civil war. Armitage introduces the book as an attempt to understand the global phenomenon of civil war that has accompanied the long peace in the North Atlantic and other wealthy countries such as Japan and Australia. As the opening and closing chapters of the book explain, its writing was inspired by the concern that ours is a world in which civil war is ubiquitous and its effects unequal. Civil wars “disproportionately . . . befall the world's poorest countries” (p. 6). Many of the civil wars of the last sixty years have become internationalized, whether through the intervention of outside parties or through spill-over crises that reshape the world beyond the battlefield. Thus while “the developed world has enjoyed a long peace since 1945, large parts of the global population have undergone an equally long trauma” (id.). While those actors do not in general have speaking parts in this book, they stand as mute witness to the significance and the horrors of civil war.

Armitage argues that civil war has remained undertheorized despite its ubiquity. He notes that there is, for example, no On Civil War to match Carl von Clausewitz's On War or Hannah Arendt's On Revolution. His aim as a historian is not to write that missing treatise, but rather “to uncover the origins of our present discontents” and explain “why we remain so confused about civil war” (p. 7). The means for reaching that understanding is a history spanning two thousand years. His book shows what historical work that adopts such a broad sweep can do, by bringing material into relation that would not be possible in a more conventionally contained historical account. This involves treating civil war “as a serial phenomenon, across time and around the world” (p. 19). Yet as Armitage himself recognizes, writing a narrative of such broad temporal scope requires difficult choices to be made about whose ideas or which events should be included as historically consequential and which left out. In his words, “[t]reating such a vast expanse of time constrains my coverage of space” (p. 22).

In addition, as Armitage notes, what counts as civil war is a contested question. Is the history of civil war a study of events that people at the time referred to as civil wars, connected by that common name? What if contemporaries disagreed over that name—for instance in debates over the naming of what is now referred to as the American Civil War? Or is it a study of events that later observers have agreed to characterize as civil wars? Is it a history of violent conflicts that share a particular set of “objective” characteristics that social scientists point to as markers of civil war? Armitage is well aware that the “problem of naming becomes particularly acute when political ideas are at stake” and that when the term used to frame a history is one like civil war, “politics precedes even attempts at definition” (p. 13). As a result, any essentially contested concept like civil war has multiple possible histories.

I would make, and indeed have made, different choices in studying the history of civil war, particularly when considering its relation to the transformation of international law over the past centuries.Footnote ⁵ However, my aim here is not to explain or defend my choices. Rather, my focus is on the choices made by Armitage in assembling the series that structures this book and in characterizing particular situations as civil wars. While Armitage presents his approach as “revealing underlying patterns or models” (pp. 19–20), I see the process of assembling such a series as far more active, involving the making rather than the finding of such patterns.Footnote ⁶ I am interested in how the series made (or, in his telling, found) by Armitage supports a particular interpretation of an idea like civil war, and in what the series presented by Armitage makes visible and what it masks.

Armitage explains that the book's focus is on “three major moments, successively Mediterranean, European, and global, over the longue durée of civil war” that illustrate the genesis, transformations, and contemporary applications of that idea (p. 22). He justifies that decision on the basis that “Western conceptions of civil war are the ones that have shaped global debates through adoption by international organizations like the United Nations and by global communities of lawyers, scholars, and activists in the twentieth and twenty-first centuries” (p. 23). He notes that given the constraints imposed by his broad temporal coverage, other relevant traditions of political thought, including the Arabic and Chinese conceptions of schism or internal war, cannot be explored. The resulting account offers an extremely rich and erudite study of one particular tradition of thought about civil war that Armitage traces from classical Rome to early modern England, on to the French and American revolutions of the late eighteenth century, to the American Civil War in the mid-nineteenth century, and to the somewhat more amorphous “worlds of civil war” in the twentieth century. Civil Wars displays the narrative ease, ability to synthesize material from a broad range of fields, and scholarly erudition that I associate with the best crossover histories written by U.S. scholars. It also shares some of the tendencies that trouble me in those writings, particularly the privileging of Anglo-American sources in the telling of global histories.

Part I, entitled “Roads from Rome,” argues that civil war was invented in republican Rome both as an event and as an idea. That Part explores Roman debates that decisively shaped conceptions of civil war over a six-hundred-year period from the first century BCE to the fifth century CE. Armitage there traces the close association of civil war with ideas of the city or civitas, explores the stakes of imagining the physical and metaphysical space of the city as a stage for war, and shows how ideas about civil war became woven into the fabric of public life in the Roman republic and the early empire. He stresses the importance of the idea that civil war took place within a single political community and the disruption involved in the very idea of civil war. While the forms of authority exercised by a magistrate within Rome and a general outside were supposed to be distinct, that separation was breached when military command was brought within the city and citizens treated as if they were enemies. Armitage argues that “Rome's heirs in the Latin West” would subsequently “perceive their own internal troubles with the help of the repertoire of examples and images drawn from the Roman corpus of writing on the subject” (p. 58), particularly that of Tacitus, Lucan, Cicero, Appian, Florus, and later Augustine. He notes the recurrent theme of subsequent histories that saw the civil wars of Rome as presaging the decline of the Roman Empire and asked whether Rome's internal strife was “the unintended consequence of Rome's success” (p. 81).

Part II, entitled “Early Modern Crossroads,” is in many ways the heart of the book. It studies the transmission of Roman concepts and narratives about civil war to early modern Europe and on to the French and American revolutions of the eighteenth century through the forms of classical education from which European thinkers drew their conceptions of civil war. Here Armitage is on home ground, having previously published histories of early modern English political thought, the Declaration of Independence, and the age of revolutions.Footnote ⁷ He shows that influential European political thinkers, including Hugo Grotius, Thomas Hobbes, John Locke, and Adam Smith, read Latin texts at school and university, and came to understand their internal power struggles through a vocabulary and set of narratives inherited from the Romans. Thomas Hobbes, for example, was deeply indebted to the Roman canon of civil war as a model for Behemoth, his history of the civil wars of England. Civil war was also a theme of Hobbes's political works De Cive and Leviathan. Civil wars were a central theme of William Shakespeare's Roman plays, including Julius Caesar and Antony and Cleopatra. Lucan's Civil War inspired John Milton and Jean-Jacques Rousseau, while Roman concepts also shaped the thinking of Hugo Grotius in his Commentary on the Law of Prize and Booty. John Locke was an attentive student of civil wars and drew on that tradition in his accounts of tyranny and rights of resistance in Two Treatises of Government. In his account of these thinkers, Armitage traces the conceptions of public life carried into early modern England through the transmission of Roman ideas about civil war.

Armitage is interested in what it means when the idea of civil war is then taken up to frame understandings of struggles within an empire (such as the American War of Independence) or struggles against monarchy (such as the French Revolution). The Swiss scholar Emer de Vattel, whom Armitage describes as the “great innovator in modern conceptions of civil war” (p. 128), acts as a bridge between early modern thinkers and the American revolutionaries. Vattel draw on the work of Grotius, Hobbes, and Locke to advance a theory of free and independent states, an argument defending the right to resist unjust rulers, and an interest in the definition of war and the rules regulating the right to go to war and rights during war. His account justified applying the law of nations to civil war and intervention by outside powers to assist the party they judged to have right on its side. Vattel's The Law of Nations was drawn upon by Thomas Jefferson and others when writing the Declaration of Independence in 1776 and served “almost as a bible of international conduct” in the era of the American Revolution (p. 129).

For Armitage, Britain's North American colonies exiting from the empire in 1776 ushered in a “truly revolutionary conception of civil war” (p. 128). Armitage notes that traditional histories of the American Revolution have resisted calling it a civil war, perhaps because of the mythology that the conflict was cohesive rather than divisive—“an act of liberation by self-identified Americans who felt their distance from Britain and demanded self-determination” (p. 135). Yet he argues that it could be understood as a civil war between American colonists and Britons, who had struggled together against the French in North America and were being asked to share the costs of their defense. It was the question of revenue-raising in support of imperial militarism that “split the empire” (p. 136). Armitage shows that numerous contemporaries framed the British imperial crisis in North America as civil war, implying close kinship between the parties. For example, the closing pages of Thomas Paine's Common Sense bolstered his argument in favor of independence from Great Britain through a narrative of civil war reaching back to the Roman civil wars and through the history of England. The language of civil war was also adopted by the Continental Congress in its 1775 “Declaration . . . Setting Forth the Causes and Necessity of Their Taking Up Arms,” which appeared a year before the Declaration of Independence and was also drafted by Thomas Jefferson. It sought to reassure “the minds of our friends and fellow subjects in any part of the empire . . . that we mean not to dissolve that Union” and seek only “reconciliation on reasonable terms . . . thereby to relieve the empire from the calamities of civil war.” Armitage concludes that the colonists in North America should be seen as one among many groups of insurgents throughout the Americas who were faced with the challenge of transforming “rebellious struggles within empires to legitimate conflicts outside them” (p. 146).

The Roman conception of civil war also offered one set of intellectual resources for making sense of the French Revolutionary and Napoleonic Wars (p. 120). The French Revolution was the “great test case for the mutual implication of revolution with civil war” (p. 147). Armitage rejects the mythologizing of the French Revolution as somehow a radical break with the past and of the conception of revolution as a dramatic event signaling change and transformation. Thus for Armitage, the French revolutionaries simply “rebottled what in other circumstances—or by other ideologues—had been labeled rebellions, insurrections, or civil wars” (p. 156). He draws on Edmund Burke's argument that both England's Glorious Revolution of 1688 and the French Revolution were civil wars and urges the reader to take seriously Burke's position that “civil war was the genus of which revolution was only a species” (p. 158).

Armitage is thus keen to stress the interrelation between the two concepts of civil war and revolution. He argues that while idealists portrayed revolutions as driven by transformative hopes and civil wars as animated by senseless motives, in fact the two were not readily distinguishable. While revolution is thought to represent “an unfolding progress of human liberation,” the “repressed truth” is that “the heart of most great modern revolutions was civil war” (p. 122). For Armitage, the result is that a force meant to be “modern, novel, and forward-looking” in fact owes “so much to one so archaic, traditional, and backward facing” (pp. 122–23). He sees nothing modern about revolution, arguing that “the page on which self-consciously modern revolutionaries rewrote the script of political change was in fact a palimpsest—underneath the new version, still very much visible, was the one transmitted by the historians of Rome's civil wars” (p. 124). Although the book does not engage with any communist revolutionary thought in detail, Armitage notes that Marx was a “keen nineteenth-century connoisseur of civil conflict, who was a student of classical history in general and of Roman political turmoil in particular” (p. 47), and points to Marx and Engels in The Communist Manifesto tracing “the more or less veiled civil war, raging within existing society, up to the point where that war breaks out into open revolution” (p. 157). Armitage here works to “uncover the modern script of revolution from these mystifications” (id.). He recognizes that “it might appear that looking for the civil war at the heart of any revolution is downright counterrevolutionary” (pp. 149–50, emphasis in original), but he does not explore that idea in any more detail. Nonetheless, the counterrevolutionary character of the argument is evident in his insistence that revolution is just history repeating, and in the rejection of the possibility that peasants, the proletariat, or the colonized seizing control of the state, the empire, or the global economy may be historically consequential political action. The effect is to deny any distinct historical significance not only to the French Revolution but also to the many other revolutions that are not discussed in his history.

Part III, entitled “Paths to the Present,” tracks developments since the middle of the nineteenth century, focusing principally on the American Civil War and on the twentieth century “worlds of civil war.” International law is a key part of the story that Armitage tells here. He argues that the nineteenth century's “great contribution to this history was the attempt to ameliorate the severity of civil war by bringing it under the domain of law” (p. 26). For Armitage, “civilizing civil war” involves bringing it within international law and this “remains an objective for the international legal community right down to our own time” (id.). In his view, the American Civil War was a turning point in that respect because “the category of civil war came firmly under the authority of lawyers for the first time” (p. 193). This raised the question of whether it was possible “to civilize civil war” or whether war could be “tamed” by law (p. 171, emphasis in original). Armitage explores the attempt to codify the rules in the context of Francis Lieber's General Orders No 100 of the Union army of 1863 as a key development, noting that Lieber's definition of civil war would continue to be relied upon in U.S. Army field manuals through to the present.

The book concludes by tracing “developments as civil war goes global over the course of the twentieth century” (p. 26). It portrays the latter half of the twentieth century as the period when “the frontiers of the community beset with ‘civil’ wars expand beyond the physical boundaries of state and empire to encompass the whole world” (id.). Perhaps unsurprisingly given the amount of relevant legal material that could have been covered relating to that period, this aspect of the book is the least satisfying for a legal audience. There are so many precedents, treaties, declarations, protocols, institutions, and techniques developed over the course of the twentieth century that have helped to structure and frame civil war or “non-international armed conflict” that it would not be possible to produce a history of that legal century in one chapter, and this is not of course Armitage's goal. Rather, his interest here is on what he continues to portray as the problems caused by the absence of international law from the regulation of civil war and the potential of international law to “civilize” civil war.

Armitage briskly covers key moments in the development of international humanitarian law in this area, touching on the negotiation of Common Article 3 of the 1949 Geneva Conventions, the drafting of the 1977 Additional Protocols to the Geneva Conventions, and the Tadič decision of the International Criminal Tribunal for the former Yugoslavia Appeals Chamber, although in far less detail than accounts offered by international lawyers or more specialist historians of the field.Footnote ⁸ He also considers briefly the 1975 resolution of the Institut de Droit International concerning “The Principle of Non-Intervention in Civil Wars,” and mentions discussions amongst U.S. political theorists and policymakers about whether the conflict in Vietnam was a civil war or a war between two states. His conclusion is that “the legal boundaries of what is or is not a civil war have continued to be flexible and dynamic” and as a result “recent efforts to bring civil war within the pale of civility remain frustratingly and lethally incomplete” (pp. 205, 207). If the laws of war were transplanted to the world of civil strife, “the world might come closer to the ‘civilization’ of civil war” through the application of “a set of legal protocols designed to humanize the conduct of civil war” (p. 208). International law in this narrative represents the valiant but failed attempt “to constrain civil war within a precise definition and the attempt to regulate it according to legal protocols” (p. 236).

Armitage's image of international law as both restraining and civilizing gives form, shape, and content to the legal material he includes in his history. He focuses largely on international humanitarian law without considering the broader conceptual architecture within which that sub-field of international law operates. That matters because international humanitarian law does not necessarily provide more constraints than the forms of law that it displaces. The idea of international humanitarian law as protective rather than permissive assumes that the forms of law it displaces are more rather than less permissive in authorizing violence. Here a historical account that attended to the broader legal and political field would have shown that while this may have been true in the context in which nineteenth century responses to rebellions, insurgencies, uprisings, or revolutions operated, it is no longer the case today, when most states are parties to international human rights treaties. The application of international humanitarian law now displaces a network of domestic and international laws that are far more protective of civilians than the laws of war.

In addition, the United States, as Armitage recognizes in the closing pages of the book, currently presents itself as engaged in a “global non-international armed conflict” that is taking place on a global battlefield. Through a reinterpretation of the right to self-defense under the UN Charter, the United States thus asserts a right to use force anywhere in the world that Al Qaeda or its associated forces are present and to do so under the asymmetric logic of international humanitarian law as applied to non-international armed conflict. It is Armitage's focus on the transformation of international humanitarian law, while ignoring the transformations in the international law governing resort to force and the protection of human rights, that makes it possible to present a picture of international law as a protective and restraining force.

More broadly, critical legal scholars have focused on the ideological work done by the notion of law as a “civilizing” force, particularly in relation to the legitimation and delegitimation of different forms of violence and power.Footnote ⁹ The very language of civilizing or humanizing carries with it a sense of colonial difference, which these laws serve to reinforce by creating an image of what count as civilized or humane practices of war. In addition, the assumption that international law is absent from the space of war and intervention, and that the solution is to bring war within the domain of international law, ignores the presence of international law as a force that already shapes war and the conditions that lead to war.Footnote ¹⁰ International law has varied modes, forms, effects, roles, and functions in relation to civil war. It authorizes some forms of violence and restrains others, recognizes some actors and not others, attributes responsibility for harm to some actors and not others, provides a means of protecting investments and property for some groups and not others, and enables the liberal economic order of free trade and navigation to continue uninterrupted during armed conflicts. It is only by ignoring this broader field that Armitage can claim that including civil war within international law would necessarily serve to humanize it. To be fair, Armitage is here reflecting a tendency in international legal scholarship to focus primarily on international humanitarian law when discussing civil war, as the widespread adoption of the international humanitarian law category of non-international armed conflict in place of the concept of civil war in contemporary legal argument makes clear. However this tendency limits our understanding of how international law has framed civil war, both historically and today.

The world into which Armitage's book arrived in 2017 was a very different one to that in which it was conceived. Indeed, Armitage notes in the afterword that “the past is unpredictable” (p. 241). “What we find historically important, what problems are worth scholarly investigation, what topics come to seem most urgent—all these change in light of current concerns” (p. 242). The opening chapter makes clear that at the time of writing, for most people in the West “civil war is more a matter of memory and metaphor than lived experience” (p. 14). The possibility that civil war may yet reenter those privileged spaces is never directly discussed in this book, although we see glimpses of that possibility in the discussion of the Los Angeles riots of 1992 or the inclusion of a description by U.S. Congressman Newt Gingrich in 1988 that while those who live in the United States “are lucky that our civil wars are fought at the ballot box, not on the battlefields, nonetheless it is a civil war” (id.).

Yet while Armitage's history treats civil war as something that happens out there, and in which the United States is involved only as a matter of foreign policy, the 2016 election of Donald Trump as U.S. president saw the intensification of a turn to the militarization of civil life within the United States. In the assault on the Capitol of January 2021 we can hear the echoes of the scene so powerfully narrated by Armitage, in which the consul Lucius Cornelius Sulla, “that pioneer in the history of civil war,” turned his troops upon Rome, marched through the Forum and took the Capitol. The entry of war into civil life signaled the beginning of the end of the Roman Republic and its offspring, the Roman Empire. The world is waiting to see what will happen now that the language and experience of war is again shaping public life within the United States. In a geopolitical context in which U.S. leadership is faltering and other powers are rising, the Arabic, Chinese, and Japanese histories of political thought noted briefly in the opening may also become a more central part of any global history of civil war and international law. In those changing contexts, this book might be understood to offer something more modest than a global history of the idea of civil war, although no less valuable. It might best be read as offering the provincial history of one tradition of political and legal thought—a European mode of thought that for a period was able to imagine itself as universal and that has profoundly shaped our contemporary situation.