This thesis examines the rationale behind the Brazilian Army's attempt to establsih effective control of the Amazon through the Calha Norte project. The project was initiated in 1985 to satisfy geopolitical needs of Brazil. The thesis argues that the rationale for Calha Norte has expanded to include not only geopolitical goals, but also a justification for the military's budget and legitimacy. Furthermore, the expanded rationale has resulted in the Brazilian army enlarging its prese,7e in the Amazon. Contrary to most of the literature, the thesis argues that the Calha Norte project has a favorable impact in the Amazon. The interests reviewed by the thesis include border conflicts, narco-trafficking and environmental conservation. Finally, the thesis recommends that Brazil expand the Caiha Norte program, and that the United States support such an expansion.