This research argue on the OAS cooperation agreement becomes United States instrument to achieve the political economy and political security. The spirit to spread of freedom and human right perceived as the character of US as a liberal democratic country. The Obama administration take a greater chance to strengthened the cooperation with Latin American countries by the OAS as a means to seize power and influence dealt with the matter of Latin America free trade agreement and drugs control. This research used qualitative research method by descriptive analysis. The data and information obtained from library research. The researcher apply document content analysis through the government publications, scholars publications, IGO reports, and other research publication. The foreign policy changes of US foreign policy under Obama administration believe in market reform and American pragmatism based on democracy and trade liberalization. The economic advancement of Mercosur triger the confidence building among Latin America countries and let them survive without US political influence. Whereas, US national security threaten by the increasing of drug trafficking from Mexico and southern area since 1980s. The OAS framework of cooperation on combating drugs trafficking developed by US as the dominant