U.S. State Responsibility á la Trail Smelter: Arms Trafficking and Transboundary Harm to Mexico

Abstract

Both President Obama and Secretary Clinton have stated that the United States accepts shared responsibility with Mexico for the Mexican drug war. The question this article will attempt to answer is whether shared responsibility for illegal arms trafficking from the United States into Mexico reaches beyond the world of political rhetoric. In attempting to examine whether there is a basis in international law for holding the United States responsible for arms trafficking into Mexico, this article will examine the international arbitration case of Trail Smelter for the principle it is credited with establishing: the prohibition against transboundary harm. It will explore whether the prohibition against transboundary harm can be applied to arms trafficking from the U.S. into Mexico by exploring the obligation to prevent harm to foreigners in the International Court of Justice case “Military and Paramilitary Activities in and against Nicaragua”, which noted the duty of states to prevent the use of their territory for the purposes of illegal arms trafficking into other States. Finally, it concludes that the United States may be responsible under the doctrine of international state responsibility à la Trail Smelter for transboundary harm in Mexico’s territory for 1) its failure to have an adequate legal structure in place that is capable of allowing it to meet its due diligence duty to prevent transboundary harm, and 2) for its failure to meet the standard of due diligence in preventing the arms trafficking.