During the past two decades the concept, among policy makers and academics, regarding that which constitutes a threat to national security has suffered significant changes. What has changed is not so much the military nature of national-security threats, but rather existing views on what causes conflict among nations and peoples. Narcotics traffic from Colombia and the region is still the most serious threat to national security , even though this traffic in the case of Colombia, clearly becomes complicated —both at a local and global level— as of the close relationship between drug trafficking and the two main guerrilla groups, Fuerzas Revolucionarias de Colombia (FARC) and the Ejército de Liberación Nacional (ELN). Throughout the past two decades the perception regarding the impact of narcotics trafficking has changed, both in Latin America and North America. The United States and Canada have accepted their own responsibility by helping producing and exporting nations through interdiction activities, crop substitution, economic and social development aid, and military aid, the latter being the focus of the Plan Colombia. Although there are those who, in the United States, are highly critical of the Plan Colombia, it is important to acknowledge that there is also considerable backing for the Plan in that country.