LAUSR

corruption, co-optation, and coercion that are often used to explain the interaction between state actors and criminal groups. The gray zone of criminality opens up the black box of informal practices and sets the table for refined systematic analysis. Furthermore, although the concept was generated in the context of the study of Mexico, it is not hard to imagine its application to other countries with high levels of violence and weak democratic rule. From an empirical standpoint, purists of ethnographic work may take issue with the quantitative tests used by Trejo and Ley. Choosing Michoacán and Guerrero for their synthetic control models is a valiant choice considering the uniquely bellicose pasts of these states. However, even if one is skeptical of the explanatory power of such methods, the authors have undeniably made a conscious effort to engage with complex phenomena through an innovative mixed-methods strategy incorporating multivariate regression models, quasi-experimental techniques, process tracing, and interviews with high-level government officials. More importantly, even with the combination of these methodologies that seek to establish causal identification, the authors are not claiming a monocausal explanation of criminal wars but rather advocate for the “development of a theoretical and empirical corpus that will lead to the systematic testing of the likely impact of political regimes, political change, and electoral politics on large-scale criminal violence” (p. 292). The robustness of the argument, however, is constrained by Trejo and Ley’s explanation of the evolution and fragmentation of drug trafficking organizations. Although they encourage us to think about the intricacies of state actors operating at the subnational level, they treat drug trafficking organizations as unitary, homogeneous actors pursuing identical goals. This is problematic because it overemphasizes rationality in decision-making processes within criminal groups and neglects explanations for violence related to principal–agent problems. That is, sometimes the violence we observe is not the result of a calculated decision by the criminal group but rather the result of shirking. As fragmentation has taken place in Mexico’s criminal landscape, we cannot discount this as an outlier explanation for violence. Furthermore, in using a narrative that emphasizes the leadership of one criminal group (the Guadalajara Cartel) that purportedly created three new cartels in the late 1980s (Tijuana, Juárez, and Sinaloa) as their starting point for subsequent turf wars, the authors assume that all drug trafficking groups want and can expand. Rather than focusing on the alleged pax mafiosa, the argument would be improved by considering the international and national developments within drug markets that created different incentives for the use of violence during the period of study. For example, although they take into account the demise of the Caribbean route and the subsequent change of drug routes to Mexico, the authors do not mention the opium production ban imposed on Turkey in the early 1970s that was crucial for enabling traffickers inMexico to supply heroin to US consumers. Given Sinaloa’s longstanding ties with the United States, the ban also made that state a key international player in the illicit drug markets, in contrast to other opium-growing regions in Mexico. Similarly, although the authors briefly mention changes in consumer preferences, the increased demand for synthetic drugs in the mid-1990s allowed groups to manufacture illicit drugs locally without requiring partners in production centers as was necessary with the importation of cocaine. In line with their argument, this change would translate into different gray zones of criminality being contingent on different production models. Beyond drug markets, the authors fail to consider that some criminal groups may diversify their criminal activities not because they are expanding drug trafficking routes but because they are moving to a different business model. In this sense, violence against civilians is not a result of turf wars, but occurs because violence needs to be public for extortion threats to be credible. This does not refute the authors’ argument of criminal groups as political actors but adds nuance to the idea that violence is bad for business. My assessment of the blind spots of the book as they relate to the business models of criminal groups does not take away from its substantial contributions. In the preface, Trejo and Ley declare that “during the long years of research and writing of this book we have always kept in mind the hundreds of thousands of civilians and their families who have become victims of criminal wars.” Ultimately, beyond academic debates, the arguments and findings of this book remind us that, when it comes to violence and criminality, carefully constructed research is not exclusively an intellectual pursuit but one of the building blocks for more peaceful societies.