As in many cities, gangs in Medellín provide order and collect 'taxes'. Why do gangs govern civilians? Some argue that criminal and state rule are substitutes. Hence, increasing state presence should crowd out gangs. But they could also be complements. States produce growth and general demand...

This paper develops a model of a war against the producers of illegal hard drugs. This war occurs on two fronts. First, to prevent the cultivation of crops that are the raw material for producing drugs the state engages the drug producers in conflict over the control of arable land. Second, to...