Abstract
Confrontational policing tactics such as the widespread use of stop-and-frisk powers promise social benefits through crime reduction, but often at important social costs. In the context of a Global South city where policing methods rely heavily on aggressive practices, including the threat to use guns during routine police stops, this study provides evidence on another set of unintended consequences of aggressive policing: undermined legitimacy beliefs. Drawing on a three-wave longitudinal survey of adults residing in São Paulo, Brazil (2015-2018), I rely on recently developed methods for causal inference with panel data and estimate the impact of a recent police stop and a recent police stop at gunpoint on perceptions of police fairness, police effectiveness, overpolicing, and police legitimacy. Effects of a recent change in treatment status are estimated by matching methods for panel data combined with difference-indifferences. While estimates are too imprecise to suggest an effect of a recent police stop on attitudinal change, police stops at gunpoint decrease expectations of police fairness, increase expectations of overpolicing, and harm beliefs of police legitimacy. Under a credible conditional parallel trends assumption, this study provides causal evidence on the relationship between aggressive policing practices and legal attitudes, with important implications to public recognition of legal authority. Keywords: Aggressive policing · Brazil · causal inference with panel data · police legitimacy · perceptions of police Confrontational proactive policing methods are often used to tackle crime in the United States (Fagan et al., 2016; Manski and Nagin, 2017). Previous work suggests that this type of policing approach can indeed contribute to reduce crime: for instance, Braga et al. (2018) showed that focused deterrence strategies are associated with crime reduction, and Sharkey (2018) argued that the expansion of criminal justice institutions through aggressive policing strategies and mass incarceration was at least partly responsible for the great crime decline in the country in the 20 th century. However, despite potential benefits in crime reduction, aggressive policing practices based on increased coercive presence might also have a range of negative unintended consequences, including costs in intrusion on the rights and privacy of innocent persons (Manski and Nagin, 2017). The same Sharkey (2018) demonstrated how the reliance on confrontational policing practices has taken a heavy toll. Some of the consequences of increased police presence reported by recent work include worse educational performance among African American boys (Legewie and Fagan, 2019), more trauma and anxiety symptoms (Geller et al., 2014), and damages in legal socialization (Geller and Fagan, 2019). Recent incidents of police violence have demonstrated that this is a major issue in the context of systemic racism in policing in the US, with law enforcement agents contributing to criminalize poor communities of color and undermine public-police relations (Epp et al., 2014; Desmond et al., 2016; Rios et al., 2020). It is important to explore adverse effects of aggressive policing practices, especially in a period of increasing globalization and outsourcing of some of those tactics across the Global South (Steinberg, 2020; Christensen and Albrecht, 2020). The Brazilian case is an instructive example. Street-level policing in Brazilian cities is conducted by armed officers of militarized police organizations, who are trained for warlike situations (Lima