Chris Kraul at the Los Angeles Times has a very nice visual about the shift of left and right governments over time in Latin America, going back to 1980. What you're really seeing is the development of democratic rule in the region. Too many people have a tendency to see elections as the "death of the left/right" in some way, without taking the larger context in mind. As I've written over and over, Latin American voters are more pragmatic than we give them credit for, and will continue seeking solutions to the problems they face. If the left can't do it, they'll look to the right, and vice versa.