As a free trade area, NAFTA requires the relatively unrestricted movement of people, goods, and services across the borders between the United States, Mexico, and Canada. Although the proponents of NAFTA emphasize positive economic outcomes for the three partners, the dependence of those outcomes on open borders inevitably brings with it the prospect of greater opportunities for transnational criminal activities, generally, and for narcotrafficking, in particular. Managing the free flow of goods and people while limiting the free flow of illegal substances and criminals is the central dilemma of the war on drugs in NAFTA. Cooperation between the member states differs strikingly, with smooth cooperation along the northern border between the United States and Canada and a troubling lack of cooperation along the U.S.-Mexico border. The different patterns in cooperation among policy makers and law enforcement agencies are largely attributable to mutual perceptions and nationalism in all three countries.