The sixteenth and early seventeenth centuries marked a deep crisis of the international political and legal order of Europe, caused by the Reformation, the emergence of some strong composite monarchies and the discovery of the New World. The chapter maps how the law of nations began to emerge as a new paradigm for the governance of Europe under whose wings rulers, diplomats and scholars attempted to advance claims to an exclusive jurisdiction over international relations by sovereign princes and republics. As such, the ‘law of nations’ functioned as a lever, an argument for power in a period of great clashes between centralising governments, opposing confessions, and regional and local elites, rather than representing a reality. The ultimate success by governments in several important states at the end of the Renaissance was facilitated to a great extent by the patrimonial and transactional nature of the states that allowed to include old, autonomous powers in the machinery of state.

The sixth volume in The Cambridge History of International Law covers the developments of inter- and transnational laws in early modern Europe (1492–1660). The preface explains how recent revisionism of traditional state- and Eurocentric views on the history of international law impacts the study of this subject and how this is reflected in the volume.

By the middle of the seventeenth century, a category of sovereign princes and polities had succeeded in monopolising jurisdiction over external relations and the internal machinery of government that allows to speak of sovereign state. The Old Regime saw the further emergence, in governmental and diplomatic practice as well as in learned writings of the paradigm of the law of nations as the preserve of sovereigns. As legal practice and literature, it also expanded in scope and mass to new regulatory fields such as the law of the sea, maritime warfare, neutrality or dispute settlement. The great treatises on the law of nations of the middle of the eighteenth century fleshed out the dualist system of law of nature and of nations that formed one of the intellectual backbones to Grotius’ work into an elaborate framework of the governance of international relations inside Christian Europe and for its imperial expansion outside.

Chapter 2 introduces the normative theory on which the book relies. Principles of natural law are guides for practical human action. The principles are “natural” because they are knowable through human reason and valid guides to action whether they have been accepted in any community’s laws. They are “law” in that they supply reasons or justifications for action. Natural law theory focuses human action on survival and on flourishing understood rationally. Natural law justifies reasoning with interests, understood as distinct components of a person’s well-being. Natural law also justifies reasoning with rights, understood as entitlements to act and be free from interference backed by claims against others. Natural rights focus social and political life on desirable, low, and uncontroversial goals like survival and freedom. Natural rights also help specialize – around distinct fields of human activity organized around people’s bodies, their capacities to make livings, their capacities to associate, and their capacities to use property.

This book introduces a normative theory of property. Property laws and social norms are justified by whether and how well they secure natural rights. The natural rights are justified by run-of-the-mill principles of natural law, which evaluate human action by whether it helps people survive or flourish rationally. The book studies how natural rights legitimate property law in general and in specific doctrines. It also studies the main topics in property law and policy – ownership, public commons, the appropriate design of property rights, rights less sweeping than rights of ownership, property torts, regulatory takings, and eminent domain. The book studies in particular the phenomenon of practical reasoning, the sphere of moral reasoning that converts fundamental moral goals into specific laws and policies to enforce in practice. A theory of natural rights contributes importantly to normative theory beyond the theories most respected today – egalitarian or progressive theories, law and economics, and approaches the book calls pragmatic.

The pontificate of Leo XIII (r. 1878–1903) was decisive in shaping the Catholic response to modernity. His primary aim was to guide the Church in coming to terms with the modern world by making a clear distinction between unchangeable truths and other teachings that could be legitimately adapted to fit the scientific, democratic, and industrial world. The centerpiece of Leo’s approach was a Thomistic revival that included several elements: (1) Thomas’ view of the universe as an ordered hierarchy of being, governed by law; (2) Thomas’ view of natural law combined with Suarez’s “transfer theory of power” that permits a variety of legitimate regimes; (3) Thomas’ teaching on private property in service to the common good combined with Locke’s natural rights to property; and (4) a notion of the rights of workers as persons that points toward twentieth-century Christian personalism. I conclude by surveying the scholarly debates about Leo’s contribution to modern Thomism and Catholic social teaching.

The chapter explores how the legal system, akin to science and economics, serves as a tool for depoliticizing human decisions. It argues that the transformation of political processes into seemingly apolitical directives is a strategic move to prevent the illegitimate use of power and violence. The status of law as autonomous and above politics is examined, tracing its historical roots to the naturalization of law and forming the basis for legitimate legal decisions. The chapter also considers Mahatma Gandhi’s nonviolent politics and Walter Benjamin’s perspective on violence within the law. The instrumental convenience of separating law and politics is examined, emphasizing the role of law in constraining politics and power. As Judith Shklar observes, the threefold approach to law in Western tradition – apolitical law, depoliticized law following parliamentary processes, and positive law imposed by hegemonic power – reflects different bases of objectification. The power of natural law, both enhancing and restricting individual freedom, is explored in the context of its capacity to disassociate from politics. The chapter concludes by discussing the broader implications of objectification in fields such as science, technology, and economics, emphasizing the impact on public trust and the diminishing space for ethical and political considerations in contemporary democracy.

In this chapter, Ezrahi analyzes the influence of philosophers like Hobbes, Spinoza, Locke, Vico, and Rousseau, as well as the Federalists, on the shift from a medieval monistic cosmology based on God to a modern dualistic cosmology, emphasizing dynamic Nature and human agency. These thinkers played a pivotal role in shaping a political order and obedience independent of divine authority, turning to Nature as the source of laws and a check on human actions. This transformation led to the emergence of new concepts, such as the state, freedom, and equality, despite their being imaginative. Hobbes pioneered the use of metaphors and empirical sciences in civic affairs. Spinoza adopted a detached scientific perspective, viewing human emotions and drives as natural phenomena. Locke presented empiricism and probability to inform political decisions through an understanding of human judgment. Vico proclaimed that political systems are based on collective political imagination, facilitating the construction of institutions and political processes rooted in commonsense. Rousseau further developed the dichotomy of Nature/Culture, highlighting its impact on politics, education, and ethics. The American Revolution marked the merging of objective Nature and human agency, giving rise to the idea of employing science to manipulate Nature.

Chapter 3 explores the final decades of the sixteenth century, a period of deep, overlapping, and abiding crisis for the New Kingdom as a result of the limitations and failures of colonial governance. At its core was the unravelling of the authority of Indigenous rulers, who were placed under unprecedented pressures by colonial authorities who misunderstood Indigenous politics with European legal and political concepts. Engrossed in increasing competition over the leadership of the colonial project, the second archbishop of Santafé, Luis Zapata de Cárdenas, and his civil counterparts tried to pursue increasingly belligerent policies to reform the lives of Indigenous people in the final decades of the century. Their rivalries, venality, and misunderstanding of local conditions and of the limitations of their own power eventually unleashed a brutal campaign of violence and dispossession on Indigenous communities in the late 1570s, with harrowing results. The blow this struck to Indigenous political structures, and through them to the colonial tributary and extractive economy, brought the kingdom to its knees.

This chapter concentrates on the pivotal figure of Jean Barbeyrac, translator extraordinaire of Hugo Grotius, Samuel von Pufendorf, Richard Cumberland, and others. A French Huguenot refugee, Barbeyrac introduced the great Protestant natural law treatises to a French (and ultimately English) audience. But Barbeyrac was much more than a translator. He recast earlier natural law theories around individual conscience and made subjective right the foundation for society and politics. Where Grotius and Pufendorf had conceived of permission or “natural liberty” as the freedom to do whatever the law did not forbid (and thus, not really a right), Barbeyrac insisted a contrario that both natural and civil law tacitly determined – and thus legalized – what was permissible for subjects to do. For Barbeyrac, rights thus took precedence over duties, though only because every action had been made permissible by God. He extended this argument to property, which originated from a God-given natural right to first possession.

Abolitionists adopted higher law to oppose the settled law which explicitly recognized chattel slavery in America. Emerson sometimes spoke on higher law but it was not his most comfortable position. Emerson was a Neoplatonist, and it is the gradualism of Neoplatonism that he embraced against the immediatism implied in higher law. But even before Emerson’s 1856 conversion to abolition, starting in 1854 Emerson began moving his self-reliance into Northern-reliance. He was working his way philosophically toward a political activism that he would, finally, enthusiastically embrace. Emerson borrowed from the Neoplatonist Plotinus the word and idea of living “amphibiously,” and that is what he learned to do.

This chapter explains how international society emerged and was globalised. Its main purpose is to explore how the European sovereign states-system expanded across the globe to become the truly international order of sovereign states that we see today. The first part of the chapter examines how the expansion of the states-system came about and how it has been analysed. The second part provides a critical discussion of how the spread of the states-system has been understood in IR. It aims provoke thinking about the enduring Eurocentrism that continues to bedevil our theorising of international politics.

Scheuerman engages with the right-wing mobilization of “Weimar lessons” in the context of the contemporary US political landscape. The chapter focuses specifically on how the political thought of German Jewish émigré political philosopher Leo Strauss was used by supporters of the Trump Administration in academic circles, based primarily at the Claremont Institute. The Weimar analogy has often been mobilized to highlight the dangers of antidemocratic political forces. The chapter, however, serves as a reminder that the redeployment of Weimar and stories about its legacy can be instrumentalized to serve authoritarian as well as anti-authoritarian purposes.

Chapter 4 surveys a wide range of friendly and hostile interstate relations in ancient societies, where war was often the normal state of affairs. Notwithstanding the numerous conflicts, polities tried in the end, through alliances and diplomatic relations, to establish peaceful relations in view of political stability and economic prosperity. The chapter analyses hospitality rules regarding foreigners, treaties between polities and the establishment of diplomatic relations, which emerged as an international system in the ancient Near East during the mid-fourteenth century bce. An alternative to diplomacy in conflict management, typical of the Greek world, was arbitration and mediation with the help of a third party. In a final section, the chapter outlines how states, when diplomacy failed, started a war procedurally. In conclusion, the chapter argues that, in the absence of an international court, the enforcement of diplomatic rules and treaties was in many ancient societies ensured by the supranational authority of the gods.

Christian Wolff (1679–1754) was a profoundly important philosopher during the eighteenth century. ‘Wolffianism,’ broadly defined as adherence to Wolff’s teachings, was taught and promoted at all the major German universities for decades. Kant was educated and began his career within an environment that was dominated by discussion between proponents of and opponents to Wolff’s philosophy. This chapter contains a complete translation of Chapter 1 of Part 1 of Wolff’s ‘German Ethics’ (1720), in which Wolff gives a general overview of almost all the core features of his ‘universal practical philosophy.’ The translation contained in this chapter therefore serves as a concise introduction to Wolff’s ethics in general, and one that is especially helpful for better understanding Kant’s explicit reference to Wolff’s principle of perfection in the second Critique (see 5:40), among other things.