By the weekend, Flores’s worst fears were confirmed: final tallies showed Felipe Calderón of the center-right National Action Party (PAN) defeating López Obrador by a mere 244,000 votes. It was Mexico’s closest-ever presidential race. The ex-mayor announced plans to challenge the tally in court, and the federal election tribunal has until early September to certify or annul Calderón’s apparent win. But no matter how the dispute plays out, the vote confirms an emerging trend in Latin America: a sharpening divide between haves and have-nots. “There are the people without running water and basic services, and those who can afford flats in New York City,” says Juan Carlos Moreno-Brid of the U.N. Economic Commission for Latin America and the Caribbean. “But this isn’t just Mexico’s challenge. Latin America is the most unequal region in the world.”

Class tensions are certainly rising in Bolivia, where socialist Evo Morales won a landslide victory last December. Residents of the more prosperous provinces approved a ballot measure last week calling for greater autonomy from the central government. In Peru, voters split sharply along class lines in last month’s runoff election: the private sector overwhelmingly backed ex-president (and eventual winner) Alan García against the populist challenge of a former Army officer. “In southern Mexico and Peru you have a lot of people who haven’t enjoyed any of the benefits of globalization, and there’s a great degree of anger and frustration,” says Michael Shifter of the Washington-based Inter-American Dialogue think tank.

The fragmentation is not universal. Robust growth has helped foster consensus in countries like Colombia, Chile, Argentina and Brazil. But Mexico proves that growth alone is not a solution for class divisions. The Mexican economy expanded by 4.4 percent in 2004 and 3 percent in 2005. But almost half of the country’s 107 million people still live in poverty, and inequali-ties are likely to widen before they nar-row. Latin America’s recent run of strong growth may peter out next year, particularly if the U.S. economy sputters. That would increase pressure on Calderón–who garnered only 36 percent of the total vote and is facing an opposition-led Congress. His first task may be to appease the many voters who feel cheated.