Over the past two decades, violent crime has reached record levels throughout the developing world. In Latin America, where a 41 percent rise in homicides in the 1990s has made it the world's deadliest region,1 citizen security has become a major priority in national polls and has contributed to the collapse of five elected governments since 2000. 2 In response, states have pursued a variety of reforms, ranging from new penal codes to restructured police forces. The most promising and popular approach to crime reduction is community-oriented policing (COP), which, in contrast to most forms of traditional policing, focuses on the causes of crime by empowering citizens, building police-community partnerships, and better using crime statistics.3 Although research on Latin American citizen security has expanded, it has fallen short in four respects. First, most studies focus on specific reforms without examining the political relationships that determine reform design and operation. Second, by situating itself within human rights debates, the literature tends to portray policing as a problem to be solved rather than as a part of governance to be developed and managed.4 Third, scholars and policymakers tend to oversimplify state-society relations in reform efforts. Finally, most studies of Latin American security reform examine specific cases and neglect cross-national analytical frameworks.5 With greater attention to these dimensions, this article explains why some reforms have succeeded when others have failed through a systematic study of community policing programs in two cities in Brazil and four in Honduras. The study shows that three independent variables - political commitment, police cooperation, and societal incorporation - determine programs' success, as measured by three dependent variables crime rate, police abuse, and citizen participation.6 In research on democratic consolidation, as well as on citizen security, greater attention should be paid to the interactions of policymakers, bureaucrats, and society. Officials' commitment to a policy must be evaluated not only based on measurements such as budgets, but by the results of specific actions taken to implement reforms. Since many policies do not show short-term results and are affected by conditions beyond policymakers' control, the process in which citizens participate and develop confidence may indicate success as much as objective criteria such as crime rates. Programs that prioritize engaging society are most likely to lead to real changes. In addition, critical to positive outcomes are mediating actors that can build civic institutions to articulate and deliver