摘要:Despite attempts to integration in South America date back to the nineteenth century, only in 2004, was created the first block to gather the 12 countries of the region, the CASA, which changed the name to UNASUR in 2007. Why this conformation occurred in 2004? The hypothesis is that the confluence of integrationist positions in the three regional powers, especially in Brazil and Venezuela, driven by one chancellor and two presidents, enabled the creation of the body. To sustain this, the work uses a series of empirical data since the military regimes in Argentina and Brazil.