The Way of the Gun: Estimating Firearms Traffic Across the U.S.-Mexico Border

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The Way of the Gun: Estimating Firearms Traffic Across the U.S.-Mexico Border

Category: Gun Markets, International|Journal: Journal of Economic Geography (full text)|Author: D Shirk, J Patterson, R Muggah, T McDougal|Year: 2013

The Problem

Mexico is experiencing a surge in gun-related violence since 2006. Yet Mexico does not manufacture small arms, light weapons or ammunition in sizeable quantity. Moreover, Mexico has some of the most restrictive gun legislation in the world. It is assumed that a considerable proportion of weapons in Mexico are illegal, most having been trafficked from the United States (U.S.). The volume of firearms sold in the United States and trafficked across the U.S.-Mexico border, however, is notoriously difficult to record. Previous attempts have involved multiplicative approximations based upon the quantity of arms confiscated at the border.

Our Approach

We tackle the challenge of estimating arms trafficking from the U.S. to Mexico differently. We apply a unique GIS-generated county-level panel dataset (1993-1999 and 2010-2012) of Federal Firearms Licenses to sell small arms (FFLs), we create a demand curve for firearms based on the distance by road from the nearest point on the U.S.-Mexico border and official border crossing. We use a time-series negative binomial model paired with a post-estimation population attributable fraction (PAF) estimator. We do so controlling for determinants of domestic demand (e.g., income, political leaning, population density, and spatial auto-correlation). We are able to estimate a total demand for trafficking, both in terms of firearms and dollar sales for the firearms industry.

Preliminary Findings

Our study finds that:

  • A significant proportion of U.S. firearm dealers are dependent on Mexican demand: 46.7% (95% C.I.: 39.4 – 52.7%) of U.S. FFLs during 2010-2012 depended for their economic existence on some amount of demand from the U.S.-Mexico firearms trade to stay in business. This percentage has steadily risen from 37.4% (95% C.I.: 28.2 – 45.0%) in 1993;
  • A sizeable and growing percentage of US firearms sales are destined for Mexico: 2.2% (between 0.9% and 3.7%) of U.S. domestic arms sales are attributable to the U.S.-Mexico traffic. This percentage is up from roughly 1.75% (between 0.66% and 3.15%) in 1993;
  • The volume of firearm crossing the U.S.-Mexican border is higher than previously assumed: 253,000 firearms (between 106,700 and 426,729) were purchased annually to be trafficked over 2010-2012. This number is starkly higher than the 88,000 firearms (between 35,597 and 152,142) trafficked in 1997-1999, during the federal Assault Weapons Ban (AWB);
  • The value of firearms sales destined for Mexico are significant and growing appreciably: The trade represented annual revenues of $127.2 million (range: $53.7 – $214.6 million) for the U.S. firearms industry during 2010-2012 – nearly four times higher than during 1997-1999, when the trade ran to just $32.0 million (range: $13.0 – $55.4 million);
  • The U.S. and Mexican authorities are seizing a comparatively small number of firearms at the border: Based on seizure reports for 2009, U.S. and Mexico authorities in recent years have been seizing just 14.7% (between 8.7% and 35.0%) of total arms bought with the intention of trafficking them. Specifically, Mexican authorities have seized roughly 12.7% of the total annual trade whilst the United States has intercepted around 2.0%.


Given these empirical findings, we conclude that ongoing government efforts to regulate firearms trade and trafficking across the U.S.-Mexico border are largely ineffective. Notwithstanding improvements in the efficacy of Mexican authorities in seizing illicit firearms between 2008-2009, they are still meager in relation to the overall volume of weapons likely crossing the border.

The scale of the trade demonstrates that the United States is an important contributor to the global supply of firearms in illicit markets. It also draws attention to the particular function of domestic firearms regulation and the concomitant responsibilities of U.S. authorities. Taken together, smarter policies are required to combat firearms trafficking, including (1) the public disclosure of disaggregated gun sales; (2) background checks geared toward identifying straw purchasers; (3) the prohibition of cash transactions in firearms sales in border states; and (4) the creation of a Mexican database of seized firearms.