Diplomacy is rarely addressed by international relations theory, and even less often given an independent role. Building on what might be called “the diplomatic turn,” the contributors to this excellent volume start from the premise that diplomatic practice constitutes international relations. The editors assert that diplomacy is not merely a practice between previously constituted political entities but is actually prior to, and constitutive of, these entities.

Diplomacy and international relations continually remake each other. Diplomats justify their countries’ practices and demands with respect to accepted law and practice. Their arguments reflect their understanding of what is appropriate, but also what is in their countries’ interests. Diplomats frequently push the envelope or seek to prevent others from doing so. The nature of diplomatic arguments—who makes them (state and nonstate actors), fora in which they are made, how others respond, and the kinds of agreements that result—allows us to track changing understandings of legitimacy and authority in regional and international societies.

Studying diplomacy is equally essential for understanding outcomes of all kinds, including those of a military nature. In wartime, officers and diplomats increasingly work in tandem, and both use diplomatic means to assert and legitimize authority. Contemporary diplomacy is about more than representation. It is also concerned with governance, that is, changing or maintaining the behavior of actors informally by bilateral or multilateral means or formally by peaceful means or violence. The chapters of this volume are accordingly process oriented, an approach that lies at the heart of my own efforts to understand international relations.

Diplomacy and the Making of World Politics is divided into three parts: the making of international institutions, making international cooperation, and diplomacy as a contested terrain.

In the first of three chapters on international institutions, Ian Hurd offers a persuasive account of the role of law. He argues that contemporary international order rests on a widely shared commitment to international law. This does not mean that law determines policy or its legitimacy, but rather than actors—state and nonstate alike—attempt to make their policies sensible and acceptable by justifying them with reference to international law. The power of international law lies with its utility in explaining and legitimizing policies. Disagreements about the law are inherent to the legal project. As a result of controversy, law changes in substance and interpretation, and in turn helps to shape foreign policies.

Tarak Barkawi follows with a chapter on law and war. Pace Clausewitz, he argues that diplomacy and war are not distinct activities. Diplomacy is central to the planning, selling, conduct, and administration of war. Modern war requires complex coordination of military and diplomatic efforts, in the field as well as at the level of high policy. The IR literature understands both activities through Eurocentric accounts based on sovereign states. This allows the great powers to distinguish war from intervention, a practice followed by data sets like Correlates of War. Juridical fictions invade IR theory, to its analytical and normative detriment.

Vincent Pouliot concludes this part with a chapter on multilateral diplomacy, which, he suggests, has become the vehicle for global governance. Permanent representation at an ever-increasing number of international institutions has allowed them to take a more significant role in governance. Diplomats increasingly occupy twin roles as national representatives and “global governors.” Pouliot explores some of the constitutive effects that this has for international relations. It introduces a new set of logic and rules for governing that depend as much on membership in cliques and the skill of actors as they do on the power of their states.

The opening chapter of Part II, by Jennifer Mitzen, further explores the differences between diplomacy as representation and as governing. Representation is unilateral, whereas governing is multilateral. It is a collective activity that presumes the production of international public power.

Iver Neumann’s chapter addresses international cooperation. Realist, and many liberal, theorists stress the role of the great powers in system maintenance. They are motivated to do this, theorists within these paradigms allege, to preserve arrangements from which they benefit, but also as a public good to provide order and security to less powerful states. Neumann convincingly explores the role of less powerful states in system maintenance, particularly in the realm of security. They have a strong incentive to play active roles in governance because they are less capable of coping with anarchy.

Cecelia Lynch contributes an interesting chapter on the role of religious actors, mostly, but not exclusively, Christian actors in shaping modern diplomacy. Throughout the twentieth century, Christian groupings were at the heart of peace movements. These movements and their supporters argued that Christian ethics—not always interpreted the same way, to be sure—should be a guiding framework for the conceptualization and practice—or abolition of—imperialism, apartheid, and war. Lynch documents how Christian conceptions influenced the foreign policies of some Western leaders and important lobby groups.

The first chapter of Part III, by Leonard Seabrooke, explores the growing role of nonstate actors in diplomacy. He focuses on economic consultants: a community of professionals that increasingly conduct political work via the service they provide for state and nonstate clients. These consultants work within the system of existing arrangements, sometimes strengthening them, but at other times subverting them. They engage in “epistemic arbitrage,” using their knowledge to claim authority and to generate symbolic and substantive economic gains.

Miriam Krieger, Shannon Souma, and Daniel Nexon examine the practice of American military diplomacy. They focus on the United States and show how each of the military services has distinctive approaches to diplomacy and the exercise of power. The authors contrast military to civilian diplomacy, and argue that a myriad of activities, from war colleges to training and assistance programs, constitute diplomacy. These and other activities help to maintain an extensive network of security governance that involves interstate and intermilitary cooperation and the socialization of foreign military and civilian actors to U.S. norms and practices.

The final chapter of this part, by Ole Sending, explores the relationship between diplomats and humanitarian actors. The diplomatic community is organized and held together by states and constitutes a thin culture distinguished by the special privileges and repeated interactions of its members. Humanitarian actors are a thicker community, held together by shared values and closer collaboration. Diplomacy nevertheless informs humanitarian practice even as humanitarian actors attempt to transcend the sovereignty and territoriality so central to it.

The conclusion to the volume, by Rebecca Adler-Nissen, seeks to explain the difficulties of diplomats and IR scholars in understanding one another. She contends that the most fundamental reason is their two different worldviews. International relations theorists subscribe to “substantialism,” which is abstract, reductionist, rationalistic, and macro in its explanations. Diplomats subscribe to “folk relationalism,” which describes peoples’ representation of their worlds in the form of stylized facts and patterns of relations. If realists construct the national interest in a top-down manner, diplomats do so in a bottom-up fashion that emphasizes the role of diplomacy in constructing those interests. For diplomats, the national interest is in practice never fixed prior to negotiations.

Collectively, these essays shed light on the diverse facets of modern diplomacy. They extend our understanding of the variety of activities that constitute diplomacy and the kinds of actors that conduct it. They convincingly demonstrate the role that diplomacy now plays in governance, not only in representation. The changing nature of diplomacy reflects and helps to shape the current practice of foreign policy and international relations. International relations theory must take diplomacy into account as a powerful force in its own right, not merely a mechanism for states to reach agreements and publicize and justify their policies.