This chapter unpacks the federal intervention in the War on Drugs and analyzes the strategies the president followed across states depending on governors’ political affiliations. We disaggregate the intervention on the military, judicial, communicative, and social policy dimensions and assess patterns of cooperation and conflict between federal and subnational authorities. Using extensive interviews with federal and subnational elites and case studies from three cities in three states, we show how Mexico’s federal government followed differentiated strategies to deal with drug violence. The president protected subnational co-partisans (PAN) in Tijuana (PAN); partially cooperated with centrist opposition authorities (PRI) in Ciudad Juáreza; but confronted leftist governors and mayors (PRD), leaving them at the mercy of drug cartels in Apatzingán. Cartels responded by launching strategic attacks and challenging their rivals in municipalities with vulnerable leftist states.Thus, the politicization of law enforcement in the War on Drugs – which was possible because Mexico transitioned to electoral democracy without developing the rule of law – became a major stimulant of violence.