The state of Rio de Janeiro has implemented a new proximity policing program known as "pacification" in select slums located in the city of Rio. The goal of the program is to regain control of these slums from armed drug traffickers through the establishment of a Pacifying Police Unit (UPP). Here I examine two slums that share a single UPP that represent extreme cases of the program's success in terms of its positive reception by residents. Building on ethnographic observations and interviews with residents and community leaders, I find that the mediating role played by the local Residents' Association is central to the program's success. Not only does the Residents' Association cooperate with the UPP by sharing its knowledge of the community, its residents, and its norms, but it receives complaints from residents regarding offensive police behavior. Residents' Association leaders then relay these complaints to the UPP Commander, who then pulls the offending officer aside to discuss his or her behavior. This mediation results in the pacification of the Pacifying Police as officers are pressured to modify their behavior. Police learn to act in ways that abide by residents' norms of respect, which eases residents' acceptance of police. Residents report that there are frequently problems when new officers arrive in the community, but that these officers eventually calm down. The Residents' Association and other informal mediators ease the acculturation of officers to the community who would otherwise be oblivious to community norms and likely to offend residents by their actions.