To do this we will analyze four factors, suggested by G. Pope Atkins, these are: 1) physical borders; 2) regional and extra-regional powers; 3) perceptions of shared identity; 4) regularity of interaction among the nations.
The chronological limits of this study were determined by a detailed analysis of government documents as well as expert interviews that haves led us to conclude that the latest wave in the ongoing process of regional integration began historically with the end of the Cold War but it was not until the 2000 Summit of Brasilia that the leaders of the region enunciated their intentions to seek a subregional South American union based on the geographic limits of the South American continent.
However, it is important to note that placing a definitive date on movements of this sort is always arbitrary at some level. Accordingly, we will work to place the formation of UNASUR in its historical context by discussing its institutional precursors; ALADI, MERCOSUR, and the Andean Community.
Finally, our decision to limit our study of the region to six countries; Argentina, Brazil, Chile, Ecuador, Peru, and Venezuela is due to time limitations imposed by the academic process itself. We selected these countries for the following reasons. Argentina, Brazil, and Chile were chosen because of their historical importance in regional balance of power politics. Venezuela was chosen because of its important role in the current direction of the integration movement, as well as its importance as a regional source of finance and energy. Ecuador was chosen because it is both the headquarters of the new union as well as a country where the author has several personal contacts that were able to provide invaluable assistance in the research of this thesis. Finally, Peru was chosen because of its large, diverse population, and its historic importance in the regional balance of power.
By Nathan Gill - Southern Affairs
 Atkins, G. Pope. 2001: 46-47 Ribadeneira, Diego. Personal interview with Ambassador Ribadeneira. Lima, Perú. 29 Feb. 2008.