This chapter explores how, after signing United Nations-sponsored peace agreements to end protracted civil wars, post-authoritarian El Salvador and Guatemala followed different trajectories of peace and violence. It first traces the development of El Salvador’s counterinsurgent state under military rule and its transformation during the civil war. It analyzes how the civil war military establishment, special military forces, and clandestine death squads capitalized on their repressive power to fight guerrillas through brutal force and on de facto impunity to engage in multiple illicit economies. The peace agreement led to an influential truth commission, but an amnesty neutralized it, preserving impunity and the counterinsurgent state. Right- and left-wing governments used counterinsurgent forces to launch Wars on Gangs, and state-gang and inter-gang warfare turned El Salvador into the world’s murder capital. It then discusses the rise of the counterinsurgent state during Guatemala’s civil war and the institutional transformations that empowered the military, elite and paramilitary forces, and death squads to lead a genocidal campaign against the Mayan people while becoming intimately involved in criminal markets. Two truth commissions exposed war atrocities and subsequently a reformed Guatemalan law enforcement, assisted by the International Commission against Impunity, dismantled criminal structures linked to the military establishment, deflating criminal markets, and driving down the murder rate.