INTRODUCTION

The sprawling collection of weaponry seized in the border town of Reynosa, Mexico, could easily have been mistaken for the arsenal of a well-equipped infantry battalion: hundreds of assault rifles, sub-machine guns, pistols, grenades, and grenade launchers arranged in eight rows that ran the entire length of the Mexican Army's spacious press room (AP, 2008). The massive cache—discovered during the pursuit of a high-ranking drug cartel member in November 2008—is illustrative of Mexico's thriving black market in small arms and light weapons, which is dominated by the country's powerful and well-financed drug-trafficking organizations (DTOs). Fuelled by billions of dollars in drug revenue each year, the cartels are among the best-funded non-state armed groups in the world.

There is little disagreement that the arsenals built with these funds are vast, but their precise composition and the sources of their contents are subjects of much debate. Do the DTOs have the ‘wealth and armies of nations’, as some claim? Does their wealth afford them access to weapons that are unavailable to armed groups of lesser means? Are there notable differences between the weapons acquired by the profit-motivated Mexican DTOs and those obtained by groups that have ideological or political ambitions and operate in other countries? This chapter attempts to answer these and other questions through data-driven analysis of illicit small arms and light weapons in countries affected by low-intensity armed conflict and high-intensity organized criminal violence.