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The Dynamics of Violence in Mexico’s Drug War


Senior Fellow
  • Associate Professor, Political Science
Senior Fellow
  • Professor, by courtesy, Political Science
CDDRL Postdoctoral Fellow, 2012-13
Research Staff, CDDRL

Since December 2006, more than 50,000 drug-related murders have taken place in Mexico. Every day, media reports are filled with images of decapitations, hanging dead bodies, de-skinned corpses, and mass graves. The vast majority of these deaths have been caused by confrontations between drug cartels competing for control of drug trafficking routes to the world’s largest market -  the United States.

What are the best strategies to control drug trafficking and the violence it generates? PovGov has an active research agenda seeking to understand how different anti-narcotic policies impact violence. One project studies the impact of military interventions and decapitation strategies.

The sharp increase in homicide rates coincides approximately with the start of President Felipe Calderón’s administration (2006-2012) and his militarized campaign to debilitate drug trafficking organizations (DTOs). President Calderón’s policies differed significantly from that of previous administrations in using a “beheading strategy” – the targeting for arrest of the highest levels or core leadership of criminal networks - as a key element of his counter-narcotics policy. On March 2009, the government released a list of Mexico’s 37 most wanted drug lords and by January 2011 the army, navy or federal policy had captured or killed 20 out of the 37.

Decapitation strategies play a significant role in counter-narcotic policies in the U.S. and other countries, but do they work? Does it matter if governments target the kingpins vs. lower ranked lieutenants? These questions are critical and should be able to inform government policy beyond the normative judgments about these arrests.

Treated and Neighboring Municipalities Treated municipalities are those where a leader or a lieutenant was captured between December 2006 and December 2010. The neighboring municipalities in orange contain strategic facilities in the Mexican transportation network.

Our project on decapitation strategies was in part funded by the Empirical Studies of Conflict a Project and by the Air Force Office of Scientific Research, grant #FA95550-09-1-0314. It was also possible thanks to the cooperation of officials within the Mexican government who facilitated the data for the purpose of the analysis.

There is controversy about whether the war against drug cartels caused some or all of the escalation of violence. A limitation of previous studies that attribute the escalation of violence to government policies is that they do not adequately address the challenges of identifying causal effects. Our empirical strategy combines a difference-in-differences methodology with the use of credible counterfactuals of policy interventions by using Synthetic Control Methods (Abadie and Gardeazabal 2003; Abadie, Diamond, and Hainmueller 2010) to construct “control” municipalities that have trends in homicides that are similar to “treated” municipalities, namely those where kingpins or lieutenants are killed or arrested. This empirical strategy requires a time series that is long enough to estimate pre-intervention or “natural” trends in violence. We use data from the National System of Health Information (SINAIS) to construct crime statistics at the municipal level for over a decade prior to Calderón's presidency.

Our results demonstrate that arrests or killings of drug cartel leaders and lieutenants have positive (i.e., exacerbating) effects not only on DTO-related violence, but also on homicides that affect the general population. Furthermore, DTO-related violence resulting from these arrests spills over to neighboring municipalities, particularly to places that are connected to transportation hubs and are thus strategic for the trafficking of drugs.

Trends of Homicides in Mexico 2000-2010 SINAIS data are quarterly homicides of males between 15 and 39 years old and homicides for the rest f the population. Government data are all homicides presumably related to rivalry between DTOs.

Our results highlight limits to beheading counter-narcotic strategies that have been common in the U.S. and abroad. The competitive structure of the illicit drug market in Mexico has created the paradoxical result that state crackdowns increase incentives for DTOs to fight turf wars by reducing the costs of fighting against the decapitated DTO. Our work hence accounts for why DTO decapitation might fail to produce the desired results while that of terrorist or rebel groups might be effective.

Updated: Dec 2013