A South American union was born as leaders of 12 nations set out to create a continental parliament.
Some see the Union of South American Nations, or Unasur, as a regional version of the European Union. Summit host Brazil wants it to help coordinate defense affairs across South America. Venezuela's Hugo Chavez calls it a counterweight to the United States.
But divisions remained. The organization's first secretary-general resigned before the organization formally met, saying some leaders had balked at his vision of putting other regional trade blocs under Unasur.