In communities deeply divided along ethnic, racial, or religious lines, how do perceptions of the police affect crime and security? In Policing for Peace: Institutions, Expectations, and Security in Divided Societies, Matthew Nanes argues that perceptions about how inclusive police forces are shape public attitudes toward the state and willingness to engage in violence against it. Inclusion in the police sends a powerful signal to marginalized groups that they will be more likely to receive equal protection under the law. These expectations, in turn, can change civilian behavior in ways that contribute to public safety—encouraging people to provide information about crime to the police and reducing support for insurgent violence.

In exploring the effects of police integration, this compelling and well-researched book draws upon a wealth of data from original surveys, administrative data on police demographics, focus groups, and interviews with citizens in Iraq and Israel, where police forces were partially integrated in recent years. Both countries are democracies with deep societal divisions, but they also differ in important ways. The level of violence in Iraq since 2003 has been much higher than that in Israel. At the same time, Iraq’s political institutions are newer and weaker than those in Israel, and its group power structures less stable, with a Shia Arab majority taking power after the US invasion following a century of Sunni Arab minority rule. That perceptions of police integration shape attitudes in similar ways in both cases suggests the book’s arguments are likely to apply in other contexts as well.

After providing a brief overview of patterns in police integration in peace agreements worldwide and developing its theoretical arguments (chapter 2), the book describes the context and success of efforts to integrate police forces in its two central cases (chapters 3–4). It tests intermediate steps in the theorized causal chain linking perceptions of police integration to behavior in chapter 5, analyzing how people form perceptions about the police and documenting how perceptions of police and the government are closely linked. The book then turns to the effects of police integration on insurgent violence in Iraq (chapter 6) and crime prevention in Israel (chapter 7). The concluding chapters of the book examine barriers to police integration and develop recommendations for implementing it in other divided communities (chapters 8–9).

Policing for Peace concludes that in both Iraq and Israel minorities who perceive police as more integrated also view service provision as fairer, access to government jobs as more open, and the likelihood of state repression in the future to be lower. In Iraq, Sunnis exposed to experimental cues that the police are integrated express less support for antistate violence. In Israel, non–Jewish citizens who perceive the police as more integrated are more willing to report crimes; an analysis of a nationwide crime victimization survey and panel data on officer demographics also shows that integration is associated with decreases in crime. Importantly, the book emphasizes that the benefits of police integration are not zero-sum—integration can improve perceptions of the state for respondents from majority groups as well. The book thus provides reasons to be optimistic about the prospects for police integration to contribute to peace.

While scholarship on power-sharing has focused overwhelmingly on other government institutions, the central contribution of Policing for Peace is to show that the composition of police forces is as, if not more, important for security. It argues that police are likely to be particularly influential in shaping public expectations of the state because of the visibility of officers in day-to-day life, as well as the unusually high levels of discretion they have to carry out their tasks and the capacity for violence that they wield (pp. 28–32).

The close attention the book pays to testing causal mechanisms, anticipating and addressing potential counterarguments, and leveraging different forms of data make its central arguments quite persuasive. Its findings resonate nicely with recent work showing that diverse officer appointments within the military can reduce the risk of civil war recurrence (see, e.g., Louis-Alexandre Berg, “Civil-Military Relations and Civil War Recurrence: Security Forces in Postwar Politics,” Journal of Conflict Resolution, 64 [7–8], 2020). Policing for Peace also deepens our understanding of the forms of integration into the state that matter. In particular, it shows that integration that creates more heterogeneity within each police unit, rather than grouping minorities into segregated units, increases perceptions of inclusion (p. 182).

These important contributions notwithstanding, the book has some limitations. While the specific, historically contingent processes that led to partially integrated police in Iraq and Israel today are well-documented in the book, it was surprising that more attention was not paid to the broader logics that might underpin exclusion from the police and other state institutions—in other words, to the reasons why efforts to integrate police are required in the first place. Relatedly, the book notes that integration into other state institutions, including the executive, legislature, and military, has been the focus of a large body of research (pp. 27, 31), but for the most part does not engage with the substantive insights from this literature.

Drawing on scholarship on rebel-military integration and ethnic staking in particular might have helped provide a fuller account of the costs and benefits of ethnic exclusion to rulers and police officers—and thus also additional insight into the potential barriers to integration. For example, in developing its policy recommendations, the book emphasizes that elites are a bigger obstacle to police inclusion than ordinary citizens. The “underlying motives” driving dominant elites to oppose integration, it argues, “stem from a desire to distribute positions in the police and other government institutions as patronage” (p. 179). However, scholarship on ethnic stacking suggests that excluding particular ethnic groups from both the military and paramilitary police units is also an important strategy for executive survival (e.g., Kristen A. Harkness, “The Ethnic Stacking in Africa Dataset: When Leaders Use Ascriptive Identity to Build Military Loyalty,” Conflict Management and Peace Science, 2021; Philip Roessler, Ethnic Politics and State Power in Africa: The Logic of the Coup-Civil War Trap, 2016). As such, even where patronage demands are less pressing, rulers may have a strong interest in building and sustaining exclusionary policing institutions.

The book also largely neglects the potential for police to constitute political actors in their own right. Other scholarship has emphasized the ways in which police can leverage their position as essential service providers for the state to evade reform efforts—even where such efforts have elite support (see, e.g., Yanilda María González, Authoritarian Police in Democracy: Contested Security in Latin America, 2020). Future work might thus seek to better understand the barriers police can pose to integration.

Overall, however, the book succeeds in demonstrating that perceptions about police inclusion can shape attitudes toward the state in ways that are important for reducing crime and insurgent violence. It deserves to be read widely and will likely be of interest to scholars of policing, power-sharing, civil-military relations, and security-sector assistance.