According to Atkins, the economic and political interests of the Caribbean states of Colombia, Venezuela, Guyana, and Suriname have been predominantly influenced by the hegemonic influence of the United States and their respective European colonial powers, while what he calls the "southern cone" nations beyond the Caribbean basin have maintained themselves relatively independent of the influence of foreign powers. Although outside interference may have been less acute in the southern states than in northern ones, none have been entirely free from it.
During the colonial period the region responded to Spain and Portugal's Euro-centric interests. After independence in the early nineteenth century the British became the most important, but not only, foreign power in the region. The Spanish tried to regain control of some of their former colonies, the French still maintained their colony in French Guiana, but neither was able to compete with the British monopoly in Atlantic maritime traffic. In the nineteenth century Britain played an important role in infrastructure development in Argentina, Brazil and Chile. However, their overall influence in the Americas diminished over time as the British Empire collapsed after the First World War and the U.S. slowly replaced them as the top geo-political power in the hemisphere. By the end of the Second World War the U.S. had effectively converted itself into the undisputed power in the region.
In terms of the historic regional balance of power, the so called ABC states of Argentina, Brazil, and Chile all competed for strategic influence in the nineteenth century. During this time period Argentina tried to expand its control over its former colonial territory in Uruguay, Paraguay, and parts of Bolivia, while containing the influence of Peru while it tried to dominate the Rio Platte Basin.
Brazil began a successful period of territorial expansion into eight neighboring countries that lasted between 1851 and 1900, and Chile sought to establish naval control over the south Pacific. These policies led to the formation of a series of strategic alliances between Chile, Colombia and Ecuador against the threat of Peruvian aggression and another one between Brazil, Chile and Paraguay against Argentina.
In 1902 Chile and Argentina signed the Pacto de Mayo formally recognizing each country's regional spheres of influence in the South Atlantic and Pacific. According to Atkins this loose balance of power in the southern cone effectively came to an end by 1920 as the much larger populations of Brazil and Argentina outstripped those of Chile. The former two countries then continued to compete for regional dominance until the end of World War II, when U.S. military aid to Brazil upset the historic balance of power between them. However, the historic competition for regional influence between these two countries continues to influence modern day relations and is a significant factor in the processes of integration that will be explored later on.
By Nathan Gill - Southern Affairs
 Atkins 2001: 54
 For a more thorough discussion of the Iberoamerican colonies see: Vanden and Prevost 2002; Bulmer-Thomas, Coatsworth, and Cortés Condes 2006; and Moreno 1978.
 Moreno, Fernando. "La Integracion Latinoamericana" Instituto Chileno de Estudios Humanisticos: Santiago de Chile. 1978.
 Barros Van Buren 1990: 54
 Atkins 2001: 58-61
 Atkins 2001: 62-63