The war on drugs has traditionally focused on arresting cartel members and destroying product, but a new research paper from political scientists at New York University suggests an unexpected force that may be driving some farmers to drug cultivation: the price of food. Plotting the dynamics of Mexican drug cartels against the price of corn between 1990 and 2010, "From Maize to Haze" posits a new dynamic in the drug trade, in which a plummeting corn price leads farmers to shift to growing poppies or marijuana, which then spurs violence as cartels fight over control over the newly created drug production.

The study's authors zero in on the plummeting price of corn, Mexico's largest agricultural product, which dropped 59 percent in the 15 years after 1990, thanks in part to the 1994 North American Free Trade Agreement. At the same time, the authors track a rise in local drug production and an increase in drug-related murders in corn-producing areas. Insight Crime points out some problems with the study, like its failure to account for the rise of cartels as an organizing structure or the launch of President Calderon's war on cartels in 2006. Still, analysts endorse the larger point about shifting agricultural trends, suggesting NAFTA may have provided an unanticipated boon to drug traffickers.