This chapter examines the evolution of defense policies in Latin America from independence to the present, focusing on how democratization reshaped the role of the armed forces and enabled the region’s growing participation in peacekeeping operations. Adopting a comparative historical and interdisciplinary perspective—combining political science, international relations, and sociology—the analysis traces the shift from conflict and militarism to cooperation and transparency. The authors highlight the transition from the National Security Doctrine of the Cold War to frameworks emphasizing civilian control, joint exercises, and regional confidence-building measures such as the publication of Defense White Papers. Drawing on empirical data, interviews, and official documents, the study identifies Argentina as a key case for understanding the interplay between institutional reform, defense diplomacy, and peacekeeping participation. The chapter concludes that Latin America, historically marked by coups and internal conflict, has become one of the world’s most stable and peaceful regions, though new challenges remain—particularly the militarization of internal security and unresolved geopolitical tensions in the South Atlantic and Antarctic spheres.