The United States often acted in Latin America as an empire. Nevertheless, there has been an obvious dissimilarity between US actions in South America and US actions in the rest of Latin America, which is illustrated by the fact that the United States never sent troops to invade a South American country. While geographic distance and strategic considerations may have played a role, they provide at best incomplete explanations for US relative absence south of Panama. The fact that the United States has had a distinct pattern of interactions with South America is thus not captured by the typical concept of Latin America. By recuperating the virtually neglected literature on regional subsystems, this dissertation maintains that researchers of inter-American relations would greatly benefit from a characterization that reflected more regional realities than entrenched preconceptions. Such a characterization would mean subdividing the Western Hemisphere in two regional subsystems: North and South America. This subdivision allows for uncovering regional dynamics that can help explain US relative absence from South America when contrasted to the remainder of Latin America. This dissertation argues that the role of Brazil as a status quo regional power in South America is the key to understanding this phenomenon. Through a historical analysis focusing on specific cases spanning three centuries, this research demonstrates that Brazil has deliberately affected the calculations of costs and benefits of a more significant US involvement in South America. While in the past Brazil has taken actions that resulted in increasing the benefits of US limited involvement in South American affairs, in more recent times it has sought to increase the costs of a more significant US presence. The concluding session considers some of the theoretical and political implications of the framework laid out by this research
