The Puzzle of Peace: The Evolution of Peace in the International System. By Gary Goertz, Paul F. Diehl, and Alexandru Balas. Oxford, New York: Oxford University Press, 2016. Pp. vii, 225. Index. $27.95.
Despite the tragic violence we bear witness to in the world--from the Syrian civil war, to the renewed threat of genocide in South Sudan, to armed conflict in Afghanistan--war is less common today than it has been for much of human history. Scholars have provided convincing data that tracks the decline of war over the past several decades. (1) When wars do occur, they are less deadly; fewer people die on the battlefield. (2) These and related statistics are often heralded as grounds for arguing that our world has entered a new, more peaceful era. (3) The logic for such is binary: if war is declining, then peace must be increasing. But this logic has remained largely untested and unproven, until now.
The Puzzle of Peace: The Evolution of Peace in the International System takes the critical discourse on war to new theoretical and methodological grounds. The book audaciously, yet convincingly, argues that the world is, indeed, becoming more peaceful. Even to assert such a claim, the book has to conceptualize, for the first time, how to study peace as a positive phenomenon and not just as the absence of war. Through this "not-war" framework, the authors explain that "[p]eace does not just happen; it is created by the actions of states and other important political players" (p. 225). The authors then provide the first comprehensive data set of factors that give rise to peace in the international system. To do so, they trace the evolution of peace from 1900-2006 by studying data about the stability of relationships between nations on a scale of peace, ranging from security community to severe rivalry. Through this novel tracing of the evolution of peace in the international system, they establish an empirical case that "[t]he international system has become significantly more peaceful over time" (p. 70).
Written by three political scientists, all noted experts and authors on international conflict, The Puzzle of Peace breaks new ground in the study of war and peace. (4) In chapter 3, the authors present their argument that "[t]he world is much more peaceful in 2006 than in 1946 or 1900 when there was little or no positive peace" (p. 70). They convincingly articulate that the rise of peacefulness between states is linked to the decline of conflict over territorial issues. This is, in part, because there is less territory to fight over in the post-World War II world, and they find that "World War II constitutes the tipping point in the international system's movement toward more peace. ... " (p. 8). They situate this claim amidst the work of others discussing the decline of war. They argue, for example, that Steven Pinker's basis for explaining the decline in violence in his book The Better Angels of Our Nature: Why Violence Has Declined (5) is "overde-termined" because he "offers far more explanations than might be necessary for his observations" (p. 74). They critique Joshua Goldstein's argument set forth in his book Winning the War on War: The Decline of Armed Conflict Worldwide (6) for its lack of depth by arguing that Goldstein's identification of the United Nations and its peacekeeping missions as the main factor explaining the decline ofwar "ignores that the organization only takes action... after the outbreak of significant violence" (p. 74, emphasis in original). They are skeptical about neorealist claims (e.g., Bradley Thayer, "Humans, Not Angels: Reasons to Doubt the Decline of War Thesis") that attribute the decline of war to European and/or U.S. hegemony on the grounds that improvements in peaceful relations among states are not "confined to Europe" (p. 75). (7) Beyond these critiques of the prevailing views about the decline of war, the authors articulate important bases for why scholars should turn their investigations to peace as a positive occurrence. In doing so, the authors not only issue a call for a new discourse on peace, they also provide empirical and theoretical tools for doing so.
The book could end there. Its empirical findings would, in and of themselves, make an original and significant contribution to the field of peace studies. Instead, the authors go on to posit why the rise of peace that they observe in the international system is occurring. It is this endeavor that will likely be of the most interest to international legal scholars.
In this vein, the bulk of the book's explanatory work takes place in part II, chapters 5--9, where the historical evolution of three norms essential for understanding the rise of peace and the development of positive relationships between nations are identified and discussed. Chapter 5 examines the way that the international system has strengthened states' normative commitments to the principle of territorial integrity since 1945. The argument is that the post-World War II international system--through its institutions and its norms--has "produced stable territorial boundaries, and the resulting stable boundaries have produced a more peaceful international system" (p. 99). The authors believe that the increase of positive peace in the international system is linked to what they call the "life cycle of territorial management norms" (p. 100), divided into three phases where the norm emerges, spreads, and becomes established and uncontested by most states. The norm against military conquest, for example, emerged after World War I but was not firmly established until after World War II, in part due to increased state commitments to enforcing violations of the norm through the U.N. Security Council and the International Court of Justice (ICJ). (8)
Chapter 6 concerns threats to global peace arising from the creation of new states. It argues that there is a norm against secession that helps reinforce the norm of territorial integrity and stable boundaries that are so essential to maintaining peace. The legitimacy of a new state or government is connected to the peacefulness of the transfer of power. The chapter presents the empirical record for both secession and decolonization and integrates the relevant data into its...