Arms trafficking from the United States to Mexico is a central issue in bilateral relations, closely linked to drug trafficking and, in particular, the lethal violence unleashed by Mexican drug trafficking organizations. Violence is always a possibility in any illegal activity, but the magnitude of the current violence is largely related to the availability of high-powered firearms being trafficked across the border from the United States to Mexico. Contributing to this are the divisions and disputes among the leaders of the drug trafficking organizations and their fight for hegemony over routes, markets and other areas created by the diversification of the profits and power derived from this business, as well as the increasing level of conflict with the police and armed forces. Other areas that cannot be overlooked include the weaknesses of Mexican institutions in charge of guaranteeing security and justice, and the decisions of those who run institutions to reduce or neutralize the capacity of criminal organizations, which could be contributing to the violence unleashed by drug traffickers.

The availability of guns alone does not necessarily generate violence, but when such violence does exist access to weapons allows it to take on greater dimensions and makes it much harder to control. Drug traffickers are obtaining increasingly sophisticated weapons at reasonably low prices thanks to easy access to guns in the U.S. market. As with drug trafficking, gun smuggling implies a relationship of coresponsibility between supplier and consuming countries; the responsibilities and the capacities of states are different, as are the actions and policies that they should adopt.