The recent expansion of the Egyptian military\u27s role in civil politics has led to uncertainty regarding the relationship between U.S. military aid and democratization. However, studies focusing on the link between foreign aid and democratization often exclude military aid from their analyses. This omission is particularly problematic given that civilian control over the military is a vital precondition for democratic consolidation, and a high percentage of U.S. military aid recipients are not yet consolidated democracies. Proponents of military aid point to the role security cooperation can play in diffusing democratic norms of professionalism. Critics worry military aid strengthens an institution that has the power to supplant elected governments using force. The civil-military relations literature suggests U.S. military aid should discourage military participation in civil politics by mitigating the external threats to recipients\u27 security, providing political support for civilian leaders, and contributing to the professionalization of the armed forces. This dissertation tests these propositions by examining the evolution of civil - military relations from the end of World War II through 2014 in three military aid recipients: South Korea, Turkey, and Egypt. The findings suggest that even when military aid improves a state\u27s security, dominant regimes are tempted to choose a strategy of deliberate politicization, granting reserved domains to officers in exchange for loyalty. In addition, weak democratically - elected leaders are more likely to adopt a policy of acquiescence, accepting the military\u27s institutional prerogatives in exchange for approval. Efforts to professionalize foreign militaries focus primarily on improving their competence, with less impact on their coherency, mission exclusivity, and respect for civilian political authority. I argue that while military aid aims to facilitate the democratization process by building armies that support democratic governance, military aid provides incentives for dominant regimes to co-opt the military, and enhances the institutional power of the military vis-à-vis the elected government in transitioning democracies