This chapter shows how partisan stability enabled police professionalization and the regulation of drug trafficking through coordinated coexistence in São Paulo. Following redemocratization in the early 1980s, São Paulo exhibited, like Rio de Janeiro, incoherent and unstable security policies that perpetuated the autonomy of a police force characterized by rampant corruption and brutality. However, the entrenchment of the Brazilian Social Democratic Party (PSDB) since the mid-1990s enabled it to implement and consolidate various initiatives to professionalize the police and reduce their autonomy. This in turn enabled a coordinated coexistence arrangement, including an implicit pact with the state’s most powerful drug gang: the First Command of the Capital (PCC). While the government has allowed this organization to expand its power in the prisons and the streets, the gang has mitigated police violence and maintained homicide rates in São Paulo among the lowest in the country.