Mexico experienced two remarkable and seemingly contradictory trends during its process of democratization in the 1990s: first, the steady and significant decline in homicide; second, the onset of criminal wars between drug cartels. Violence patterns before Mexico's transition to democracy have received very little attention in the literature, which has been overwhelmingly focused on the explosion of drug-related violence under democracy. Trejo & Ley improve our understanding of one of these trends, explaining that drug cartels went into criminal wars as the country democratized because political change at the subnational level destabilized previous relationships between criminal organizations and the state. This increased uncertainty about state protection of criminal actors and business, which in turn created incentives for violence. Their empirical analysis is based on an impressive data collection on the number of killings attributed to organized criminal organizations and the number of attacks against public authorities, both for the period 1995–2012. Using different statistical techniques and dozens of in-depth interviews, they show that subnational changes of power was associated with the increase of criminal violence. The book also explores the escalation of violence after the transition to democracy, showing that municipalities in states ruled by left-wing governors tend to experience higher levels of violence between 2007 and 2012. Votes, Drugs, and Violence offers compelling evidence that states are heterogenous actors and that political processes substantively shape criminal wars in Mexico, suggesting that politics ought to be at the center in empirical studies of criminal violence. Highly recommended, and not just for specialists on Mexico and criminal violence in Latin America.