With the recent events in Paraguay and the role of Mercosur and the OAS in responding to political events, the issue of regional integration in Latin America has dominated headlines recently. However, as Shannon O’Neil reminds us, regional integration is a project that is more than 200 years old:
Chavez and his contemporaries are not the first leaders to make such promises. South America’s first grand integration efforts began in the early nineteenth century under the leadership of General Simón Bolivar during the wars of independence. He envisioned uniting northern South America into Gran Colombia, and creating a league of American republics with a common military, a mutual defense pact, and a supranational parliamentary assembly. This dream, and Bolivar’s presidency, ended in 1830.
After World War II, integrationist efforts reemerged. In 1947 nineteen nations (which later became twenty three) signed the Inter-American Treaty of Reciprocal Assistance (also known as the Rio Treaty), where they vowed to defend each other against outside aggression. The Organization of American States (OAS) followed in 1948 (building on a previous turn-of-the-century institution), promising to promote social and economic development through a four-pronged emphasis on democracy, human rights, security, and development. In the late 1950s the hemisphere came together to form the Inter-American Development Bank (IDB), designed not only to encourage economic development but also to advance regional integration through its internal Institute for the Integration of Latin America and the Caribbean (INTAL).
In 1960, Argentina, Brazil, and Mexico led their neighbors in the creation of the Latin American Free Trade Association (ALALC), the first attempt at a regional intergovernmental body. Its goal was to establish free trade throughout the whole region in twelve years (it failed). This effort was renewed in 1980 by the Latin American Integration Association (ALADI), which promoted a more gradual approach to creating a common market (it is still officially in the works).
Sub-regionally, Bolivia, Colombia, Ecuador, and Peru came together to create the Andean Community (CAN) to promote Andean integration in 1969. In the late 1980s onetime rivals Argentina and Brazil, began negotiating agreements that evolved into Mercosur (bringing in Uruguay and Paraguay along the way). Bilateral relations have advanced as well, with over fifty trade agreements signed with neighbors in as many years.
I highly recommend you read the whole thing here.