This chapter uses the Latin American case studies presented in the previous chapters to identify general cross-national patterns and historically ground the theory and statistical findings about transitional justice’s (TJ) violence prevention effect. It first shows that during the Cold War all six countries developed counterinsurgent states with striking similarities under autocracy. In all cases, authoritarian specialists in violence capitalized on their power to kill with impunity to dominate the criminal underworld. It then discusses how TJ was a fork in the road. The adoption of robust TJ processes, combining strong truth commissions and criminal prosecution of perpetrators, allowed Argentina, Peru, and Guatemala to dismantle counterinsurgent states, preventing criminal wars and reducing violence and gross human rights violations. But the persistence of state impunity and the survival of the counterinsurgent state led to Wars on Drugs or Gangs or Crime and to turf wars that resulted in mass atrocities in Mexico, El Salvador, and Brazil. The final section discusses how in cases with robust TJ the institutionalization of accountability policies can contribute to the development of self-sustaining peaceful democracies, and how a reformulated TJ toolkit can serve democracies with persistent impunity, trapped in deadly criminal wars, enter into paths of peaceful reconstruction.