WASHINGTON—While the world was focused on the tragic events taking place in Lebanon and northern Israel, something very disturbing happened in South America last week. The trading bloc known as Mercosur (the South American common market), at its summit meeting in the Argentine city of Cordoba, formally supported Venezuela's bid for one of the two Latin American seats on the United Nations Security Council. Venezuelan President Hugo Chavez had worked the summit to make sure he could defeat Guatemala, Washington's preferred candidate, and gain the coveted seat when Argentina's two-year term expires in October. Chavez wants to become a world...