We document that the spread of the Mafia in Sicily at the end of the 19th century was in part shaped by the rise of socialist Peasant Fasci organizations. In an environment with weak state presence, this socialist threat triggered landholders, estate managers and local politicians to turn to the...

We investigate how criminal organizations strategically use violence to influence elections in order to get captured politicians elected. The model offers novel testable implications about the use of pre-electoral violence under different types of electoral systems and different degrees of...

We analyze a unique data set detailing the financial activities of a drug-selling street gang on a monthly basis over a four-year period in the recent past. The data, originally compiled by the gang leader to aid in managing the organization, contain detailed information on both the sources of...

The Ku Klux Klan reached its heyday in the mid-1920s, claiming millions of members. In this paper, we analyze the 1920s Klan, those who joined it, and the social and political impact that it had. We utilize a wide range of newly discovered data sources including information from Klan membership...

Gangs govern millions worldwide. Why rule? And how do they respond to states? Many argue that criminal rule provides protection when states do not, and that increasing state services could crowd gangs out. We began by interviewing leaders from 30 criminal groups in Medellin. The conventional...

Canonical models of crime emphasize economic incentives. Yet, causal evidence of sorting into criminal occupations in response to individual-level variation in incentives is limited. We link administrative socioeconomic microdata with the universe of arrests in Medellín over a decade. We...

Why does illegal trade often flourish without formal enforcement, but sometimes fail? Why do illegal trade-reducing policies often fail? Why do States often appear to tolerate illegal trade? A model of trade with cops and robbers provides answers. `Safety in numbers' is a key element: the...

Weak states enable private enforcement but it does not always fade away in the presence of strong states. We develop a general equilibrium model of the market organization of enforcers (self-enforcers, competitive specialized enforcers or monopoly) who defend endowments from predators. We...

While the advent of cryptocurrencies and digital assets holds promise for improving and disrupting financial systems by offering cheap, quick, and secure transfer of value, it also opens up new payment channels for cybercrimes. A prerequisite to solving a problem is understanding the nature of...

Adequate wages are an important tool to shield public officials from special interests and corruption. But what is the equilibrium effect of higher wages in the presence of criminal pressure groups, who use both bribes and violence? By means of a regression discontinuity design, we show that an...