BUENOS AIRES — Hugo Chavez's defeat in a plebiscite designed to prolong his rule and increase his power will inspire important changes not only in Venezuela, but across Latin America. Until the vote last Sunday, South America was divided into three blocs:

Populist, powered by oil and gas (Venezuela, Bolivia, and Ecuador), with their Marxist model societies, Nicaragua and Cuba, propped up by Chavez's "petrodollars."

Social democratic (Brazil, Uruguay, Chile and Peru).