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The Puzzle of Peace: The Evolution of Peace in the International System

The Puzzle of Peace: The Evolution of Peace in the International System by Gary Goertz, Paul F. Diehl, and Alexandru Balas. Oxford University Press, 2016, 264 pp.

As an empirically based study on the evolution of peace in the international system, The Puzzle of Peace is a monograph that breaks new ground in international relations literature. The authors contend that current definitions of peace are negatively defined, leaving scholars and policy makers to think of peace as the absence of violent conflict. Rather than a negative definition, the authors engage the concept of peace on its own terms, reconceptualizing peace in the context of positive interactions between two states in a cooperative relationship. In doing so, they are able to construct a dataset on international peace and provide a series of empirical assessments to determine if the international system has become more peaceful over time. Such work represents the most systematic effort to date in evaluating whether the international system is simply less conflict prone or actually more peaceful—a distinction that should matter for policy makers and academics.

To accomplish this task, the authors begin by making a convincing case that peace as a concept is relatively unexplored. How do we know this? A cursory examination of the conflict literature, for example, makes this quite clear. Most research focuses on the likelihood of violent conflict as the outcome to be explained, with variables including territorial competition, regime type, and rivalry involvement serving as the main causal indicators of a state’s willingness to use military force. Unlike violent conflict, however, the authors contend that peace is a relationship and thus must be explained not just by the absence of such indicators—for example, a lack of territorial competition increases peace—but rather by the pattern of interactions within a relationship. In other words, a relationship categorized as peaceful should be one that is dominated by cooperative and peaceful interactions—not simply a lack of hostile ones.

This logic and conceptualization of peace lead the authors to the introduction of a peace scale, ranging from very hostile to very peaceful relationships between states in the international system. This peace scale, including the process and criteria for identifying where relationships fall on the scale, is explored in detail in chapter two. The authors also identify five categories along the scale: severe rivalry, lesser rivalry, negative peace, warm peace, and security community and include the types of indicators associated with these categories—presence of war plans, presence of conflicts, status of main issues in conflict, types of communication, types of diplomacy, and types of agreements between states. All together, the peace scale serves as a primary contribution to the field in that it paves the way for a new research agenda on the quality of relationships between states in lieu of a dichotomous hostile or peaceful categorization that obscures a range of diversity in the types of relationships between states. There is a difference, for example, in the relationship between Israel and Egypt compared to that of France and Germany—even though both relationships often are thought of as “peaceful” in most empirical analyses.

While the creation of the peace scale itself represents an important contribution, the authors return to the original question and employ the scale to explore how the international system changed over the course of the twentieth and early twenty-first centuries. With data dated mostly through 2006, the authors empirically demonstrate that the number of rivalry relationships has decreased over time, while the number of peaceful relationships has increased—with both observations together suggesting a more peaceful system. Also of note is the authors’ finding of warm peace as a post–World War II phenomenon, the explanation for which is tied to the rise of regional economic integration organizations—for example, the European Union—that help develop and strengthen cooperative relationships over time.

The authors do not only evaluate trends and demonstrate that we live in a more peaceful system but also use the second part of the book to put forth a detailed explanation as to why this is the case. In sum, they argue that the development of norms regarding territory (norms against conquest, new states, and territorial change), conflict management, and maritime behavior—for example, the United Nations Convention on the Law of the Sea—have helped to push state relationships in more peaceful directions. Primarily, these norms have motivated states to utilize nonviolent means to address conflicts in lieu of the use of force. The use of these nonviolent means subsequently prepares states to move relationships away from the rivalry and negative peace side of the scale toward warm peace. And although the authors do not explicitly state this, when considered in the context of increasing institutionalization of the system in general (for examples, regional trade agreements and regional security organizations), there exists a more permissive environment for the development of peaceful relationships among states. To this point though, the authors offer words of caution: a majority of state relationships (particularly noncontiguous pairs) may be stuck in a negative peace—something that has potential implications for major and regional power relationships, such as US–Chinese relations.

In sum, The Puzzle of Peace is a good start to a new direction of research in the area of peace, utilizing solid empirical data to assess and explain trends of peace beyond the absence of violent conflict. As with any good start, there are a range of limitations to the work, of which many the authors are aware. For example, a greater systematic examination of the relationships within the warm and negative peace categories would be useful. Is the transition from negative to warm peace explained by a straightforward functionalist approach to state relationships (augmenting existing norms), or are there a range of other factors that are less empirically malleable that must be considered— culture, identity, and so forth? Are newer challenges to security a potential source of hostility between states such that current trends could be reversed? These are a few issues of concern to policy makers and those interested in international conflict and security that could be addressed. Putting these limitations aside, The Puzzle of Peace is a recommended read for those interested in the study of international peace as it provides a useful analytic and conceptual tool to understanding state relationships in a more nuanced and relevant way.

Derrick Frazier, PhD

Associate Professor

Department of Political Science

University of Alabama

"The views expressed are those of the author(s) and do not reflect the official policy or position of the US government or the Department of Defense."

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