This book by Brett Kyle and Andrew Reiter does what no other volume before has done: it provides an overview of military justice systems in the modern world and examines the ways in which they are created and changed. Although parallel legal systems of the armed forces are common in democracies and autocracies, the political science literatures on civil–military relations and on judicial systems have mostly ignored the role of military courts and the implications of military justice for democracy, the rule of law, and the protection of human rights. This book has the ambition to fill that gap, and in doing so, it examines three key questions. The first one concerns the evolution of military justice systems worldwide. Second, the study seeks to explain the varying degree to which military courts are subordinated to civilian control. Third, it investigates the relationship between legal subordination of the military, democratic civil–military relations, and human rights. To address these questions, the authors combine thorough conceptualization and theory-building, statistical analysis of an original dataset that compiles information about military justice systems in 120 countries, and historical case studies.

The book is structured in eight chapters. Following the introduction, chapters 2 and 3 present the conceptual and theoretical contribution of the study. The authors define legal subordination of the military as “the degree to which military courts are subordinated to democratic, civilian control” (p. 5). Building on recent approaches in the study of civil–military relations that understand civilian control as a continuum ranging from uncontested civilian supremacy to complete military dominance over state and politics, the authors develop a “conceptual typology” (p. 35) of three distinct systems of military legal subordination. It ranges from full subordination (military courts only try military personnel for a narrow set of military crimes); to jurisdictional contestation (military courts have jurisdiction over military and nonmilitary crimes committed by soldiers, but not civilians); to military overreach (military courts have jurisdiction over nonmilitary crimes and the civilian population).

The authors apply this typology to a sample of 120 countries in the period from 1800 (or the year of the creation of military courts) until 2017. Analyzing their data, Kyle and Reiter find that the so-called third wave of democratization correlates with the global rise of systems of full legal subordination and the decline of systems of military overreach and, to a lesser extent, jurisdictional contestation. Military legal subordination is the rule in Western Europe and in postcommunist Eastern Europe. Interestingly, Eastern Europe since the late 1950s has had even more success in curtailing the military’s legal power than has Western Europe, which may suggest some incoherence in the author’s coding of states as cases of military legal subordination to democratic, civilian control. Among the other regions, Latin America has seen the most dramatic recent changes from military overreach to full subordination, whereas in the Asia-Pacific region and sub-Saharan Africa, changes have been fewer or less successful and jurisdictional contestation is more common—a finding that reflects broader regional trends in democratization and regime hybridization. Furthermore, the three types perform differently in terms of quality of democracy, levels of repression, and the protection of civil liberties. However, because the authors compare group averages for the period 1974–2017, it remains unclear how much variation exists within each category or whether shifts from one type to another lead to more democracy, less repression, and better protection of civil liberties. Although the authors seem to believe that better legal control of the armed forces contributes to more democracy, testing causal relationships between those different phenomena would have required a different research design.

The question of what factors lead to changes in military judicial systems is discussed at a theoretical level in chapter 3. Here, Kyle and Reiter present a framework for understanding how civilian actors are able to gain or lose legal control of the armed forces. According to their “model of change,” a “critical juncture” (e.g., a regime transition, civil war, or terrorist incidents) is a prerequisite for change in the type of military legal subordination. The process of change is driven by the interactions of three key actors—government, civilian courts, and the military—which are subject to international and domestic influences. Although the authors could have been more explicit in their conceptualization of causal mechanisms and theorization of explanatory variables, their framework offers a useful heuristic for further case studies.

The following chapters look at empirical country cases. The authors have carefully chosen them so that there is variation along two dimensions: the causal pathways to reform and the outcome of such causal processes. Chapter 4 presents a paired comparison of Portugal and Colombia. The two cases represent different pathways from jurisdictional contestation to full legal subordination of the military: through democratic transition (Portugal) and through a protracted struggle among the three key actors and international and civil society actors (Colombia). Chapter 5 compares Indonesia and Fiji, which represent the same outcome (jurisdictional contestation) but which is achieved through different pathways: stalled reform from military overreach to full subordination in democratizing Indonesia versus backsliding from full subordination as a result of political polarization and military intervention in Fiji. Chapter 6 analyzes two cases of military overreach. In post-authoritarian Brazil, the continuation of military overreach is the result of unreformed practices from the authoritarian past, whereas in post-2014 Pakistan, it is a result of backsliding from a “successful” (but short-lived) reform. Finally, chapter 7 draws inferences from a comparison of two episodes of transition from subordination to military overreach and back again in the United States: the Civil War and the post–9/11 War against Terror. Chapter 8 summarizes the findings, discusses their practical implications, and suggests directions for future research.

Overall, Military Courts makes five important contributions to the literature. First, it develops a much-needed conceptualization of military legal subordination. Second, it presents a useful framework for analyzing the “politics of military justice.” Third, it demonstrates that, after their initial establishment, military justice systems are resistant to change. The transition from authoritarianism to democracy is often associated with positive change, but it is neither a necessary nor a sufficient condition for a shift from less to more legal subordination of the armed forces. Fourth, it shows that systems of full subordination are fragile and may erode as a result of autocratization or in response to the rise of new security threats. Fifth, the book identifies different pathways to reform and key players and key factors that shape the politics of failed, stalled, or successful reform toward legal subordination of the military.

Still, no book is perfect, not even an excellent study such as this one. For example, a glance at the impressive dataset compiled by the authors raises the question why they did not employ more statistical analyses of the causes and consequences of military legal subordination worldwide. Although this reviewer is sympathetic to the definition of legal subordination in this book, the authors seem to suggest that full subordination is only possible in democracies (which would contradict their own findings for Eastern Europe). With that said, this book remains an impressive piece of scholarship, one that should attract the attention of a broad audience of students, experts, and practitioners in the civil–military field.