Over the past three decades, Brazil and Argentina’s rapprochement paved the way for the two largest economies in South America to end their economic and military rivalry and commence a promising effort to institutionalize the process of regional integration in South America.* The Common Market of the South, or Mercosur, was the chief creation of that initiative and was quick to embrace Uruguay and Paraguay. Last year Venezuela became Mercosur’s fifth member, and the bloc is expected to become even bigger as Ecuador and Bolivia seek membership in the near future. But bigger does not necessarily mean better or stronger. […]