Enlightenment Ideals of Limited Warfare

Chapter 4 looks at the doctrines of ius in bello and ius post bellum in the Enlightenment theory of regular war. It argues that the laws of regular war and its conclusion embody maxims of sound policy in the public administration of a war’s destruction. The laws of war are underwritten by the assumption that states share an interest in setting reciprocal limitations on their use of force. But while the rules of regular war can be upheld in self-enforcing equilibria, these are always fragile and unstable. The chapter proceeds by looking at several specific areas in the practice of regular warfare and identifying the strategic logic behind the law and its possible breakdowns. The task of the Enlightenment jurists, as they understood it, was to help rulers and military men better see that it was in their best long-term interests to sustain and comply with the laws of war.

Hugo Grotius on Solemn War and the Difference Sovereignty Makes

Chapter 2 turns to the work of Hugo Grotius, specifically to his account of solemn war in De iure belli ac pacis. The chapter examines why Grotius introduced the solemn war concept alongside his version of the scholastic concept of just war. While just wars are constrained by principles of just cause and corrective justice, solemn wars are eminently permissive affairs, really a sovereign prerogative to use force against all enemy subjects. The chapter discusses why Grotius thought solemn wars should be the exclusive privilege of sovereigns and why they could be so permissive. It argues that for him the rules of solemn war governed the foreseeable effects of war, and their value rested in their power to minimize the lethality, extension, and duration of war. If justice mandates that rulers wage only just wars, prudence dictates that only the rules of solemn war be included in the law of nations.

Humanizing War in the Nineteenth Century

Chapter 5 examines the integration of the concept of humanity as a legal category into the laws of war in the late nineteenth century. It looks at the writings of Francis Lieber, Johann Caspar Bluntschli, and Gustave Moyner, all of whom were influential publicists and highly articulate voices in the early stages of codification of the laws of war. The chapter highlights the tensions that resulted from integrating the humanity concept into the background paradigm of regular war, and it examines more broadly the deeper transformations in international legal theory that enabled this to happen. The channeling of the humanitarian agenda through international law produced a novel understanding of the laws of war as constituted by two fundamental principles in tension, necessity and humanity. This persistent duality continues to confuse our moral appraisal of the laws of war up to the present.

Regular War and Resort to Force in the Enlightenment

Chapter 3 turns to the Enlightenment and looks at how Christian Wolff and Emer de Vattel—two of its foremost international thinkers—articulated the doctrine of ius ad bellum in the theory of regular war. The chapter shows that they gave legal weight to both sovereign standing and the justice of the cause, but their views on just cause departed radically from scholastic doctrines of just war. They understood the justice of a cause not in analogy to a legal trial but rather in the context of the international practice of publishing “war manifestoes” that offered plausible reasons for waging war. Such reasons had to be framed in the language of the law of nations and show that sovereigns took seriously state rights, but they belonged to a broad understanding of sovereign judgment in which usually all lawful enemies at war could simultaneously offer plausible reasons for war.

Political Theology, Ius Gentium, and Just War in Spanish Scholasticism

Chapter 1 focuses on the early modern theologians and jurists of Spanish scholasticism. It begins by discussing the theological and metaphysical premises on which they built their doctrine of just war, and then turns to examine how they used the vocabulary of the Roman ius gentium in their construction. The chapter underscores the theologians’ self-understanding as providers of guidance for priests administering the sacrament of confession. The law of nations was central to their solution to the questions of whether and how war could be fought without sinning. Rulers who waged war to enforce their rights were free of sin, as were also soldiers who followed the command of legitimate rulers. While this solution worked for confession, it created a juridical problem the scholastics recognized but did not solve: rulers are judge and party in disputes that lead to war.

Epilogue

We have seen in the preceding chapters how the modern laws of war evolved historically from largely self-enforcing customary norms and practices in European inter-state warfare. In Vattel’s account of regular war, belligerent states comply to the extent that they take it to be in their best interest to do so. The most important interest is to keep the destructiveness of war within certain limits, but also important is the anticipation of onerous consequences from legal breaches, either in the form of direct reprisals or from developing a reputation for savagery that could be harmful in the future....

Introduction

The Introduction situates the book within current debates in the historiography of international law. While the book’s sources are examined in their historical context, contextualist approaches to intellectual history can emphasize to different degrees theoretical or historical dimensions. This book largely emphasizes the former. Relatedly, contextualist legal history can be purely historical or used as an instrument of critique of the present. By helping to reveal the various interests that go into the making of legal norms and vocabularies, and by showing from the outside the legitimizing function of legal norms, legal history can unsettle contemporary understandings of the law. However, when instrumentalized as critique, intellectual history risks focusing excessively on the present and become anachronistic.