Although drug trafficking organizations (DTOs) exist and have an effect on health, crime, economies, and politics, little research has explored these entities as political organizations. Legal interest groups and movements have been found to influence domestic and international politics because they operate within legal parameters. Illicit groups, such as DTOs, have rarely been accounted for—especially in the literature on interest groups—though they play a measurable role in affecting domestic and international politics in similar ways. Using an interest group model, this dissertation analyzed DTOs as illicit interest groups (IIGs) to explain their political influence. The analysis included a study of group formation, development, and demise that examined IIG motivation, organization, and policy impact. The data for the study drew from primary and secondary sources, which include interviews with former DTO members and government officials, government documents, journalistic accounts, memoirs, and academic research. To illustrate the interest group model, the study examined Medellin-based DTO leaders, popularly known as the “Medellin Cartel.” In particular, the study focused on the external factors that gave rise to DTOs in Colombia and how Medellin DTOs reacted to the implementation of counternarcotics efforts. The discussion was framed by the implementation of the 1979 Extradition Treaty negotiated between Colombia and the United States. The treaty was significant because as drug trafficking became the principal bilateral issue in the 1980s; extradition became a major method of combating the illicit drug business. The study’s findings suggested that Medellin DTO leaders had a one-issue agenda and used a variety of political strategies to influence public opinion and all three branches of government—the judicial, the legislative, and the executive—in an effort to invalidate the 1979 Extradition Treaty. The changes in the life cycle of the 1979 Extradition Treaty correlated with changes in the political power of Medellin-based DTOs vis-à-vis the Colombian government, and international forces such as the U.S. government’s push for tougher counternarcotics efforts.