This chapter develops the closure thesis—a theoretical framework for understanding the inter-related dynamics of political equality and inequality in the international system based on joining the neo-Weberian concept of social closure and the economic idea of club goods. The closure thesis consists of a constitutive and a causal logic that together contribute an explanation for the reproduction and transformation of political inequalities, understood as the distribution of participatory and procedural rights. The closure thesis makes a constitutive and a causal argument: first, that institutions create rules of closure that over time have narrowed—rather than expanded—the type of political actors considered legitimate participants, thereby constituting members as categorical equals and non-members as categorical unequals; second, that as institutions respond to normative or functional pressures to be include more, and more diverse, states, incumbents face strong incentives to respond by protecting their privileges through institutional designs—such as assimilative multilateralism, hierarchical multilateralism, and exclusive multilateralism—that distribute procedural rights unequally. The closure thesis thus contests the view that the globalization of the international system has been a process of greater inclusiveness of formerly marginalized actors accompanied by a more egalitarian and even democratic multilateral institutional order.

This chapter argues that the emergence of what we recognize as the modern international system develops through evolving practices of diplomacy. IR literature has increasingly paid attention to the early modern development of diplomacy to understand the origins of the system. This chapter offers a distinct interpretation of the importance of diplomacy from the perspective of the closure thesis. In contrast to the typical account of diplomacy as mediating the political fractures that resulted from the breakdown of Christendom, it argues that the adoption and diffusion of specific diplomatic practices, such as the permanent resident ambassador, facilitated closure and boundary-drawing by narrowing the types of actors invested with rights of political representation. Diplomatic practices emerged in part as a means of producing common goods and securing privileged access to those goods for some political actors, while facilitating the political exclusion and subordination of others. The chapter concludes with a discussion of the argument’s contemporary relevance. In reflecting on an historical age in which the sovereign state was not yet the only legitimate political agent, the contemporary question is whether today’s legal and representational rights at the global level can or should be emancipated from the state.

The international relations (IR) literature appears to be divided into two fundamentally different views about the basic structure of the international system and its institutions. On one view, the expansion and opening of international institutions in the 20th Century to include more actors and greater geographical reach, combined with strengthening democracy norms, are driving the democratization of international institutions. At the same time, a more critical literature is emerging that instead views the system as permeated by multiple forms of hierarchy and deep structures of domination. This chapter, in contrast, argues that political equality and inequality obstinately co-exist in international institutions because of their very role in regulating access to collective goods. It develops what I call the closure thesis to explain how institutional designs reflect an ongoing struggle between the assertion of equal rights and the preservation of unequal privileges. This argument requires re-thinking three premises: that equality and inequality are antagonistic; that greater inclusiveness typically promotes a move towards greater equality; and that international institutions provide global public goods. This chapter elaborates on these points, situates them in the literature, introduces the closure thesis, and outlines the rest of the book.