Bogotá, Colombia

WHITE and modern in a neighborhood of mud and brick, the Jardín el Porvenir kindergarten occupies half a dozen two-story concrete-and-glass pods scattered like children’s blocks on an oval campus here. A metal fence shaped like a bamboo forest encloses the school, which borders a basketball court and plaza where people gather and teenagers play soccer. From inside the school, children look out on the neighborhood. From the outside, the kindergarten is a landmark and social magnet for a corner of a poor, sprawling district, Bosa, southwest of this city’s center.

Less than a decade ago the big story here involved a pair of pioneering mayors, Antanas Mockus and Enrique Peñalosa, and the transformations they brought about in a capital notorious for drugs and terrorism. Mr. Mockus focused on cultivating a culture of civil society, on seemingly little things like obedience to traffic signals, which were really about big things like promoting civic self-esteem, a sense of shared responsibility for the welfare of the city and a climate of workable streets and sidewalks. Then Mr. Peñalosa, his successor, promoted public space and tackled infrastructural improvements, installing bike lanes and a rapid bus system called TransMilenio that extended to the expanding population of poor people occupying remote districts like Bosa. Optimism boomed.

But the bus system has deteriorated during the last several years, a victim of its own popularity but also of the failure by recent leaders to expand routes as promised, repair crumbling roads, relieve the overcrowding and fight crime. Green-minded laws fashioned to reduce car traffic and pollution, a big problem here, have perversely ended up, fueled by the TransMilenio’s woes, encouraging more Bogotans to get second cars and buy motorcycles. The ouster and arrest of another mayor last year on corruption charges was the last straw.

Bogotá had been “a cause,” as Mr. Mockus put it. Now it has become a problem.

“We’re Latin,” he explained. A deadpan, wry, highly unconventional politician and former mathematics and philosophy professor, Mr. Mockus famously mooned student protesters as a university president and as mayor went on television while taking a shower to demonstrate the virtues of saving water. “The worst thing for a Latin man is to find himself raising another man’s child,” he told me when we met recently. He was talking about the refusal by many Colombian politicians to adopt plans their predecessors conceived, instead preferring to invent their own. So the ousted mayor, Samuel Moreno, had argued for a metro to deal with what the buses couldn’t seem to handle, which may well be necessary in a city whose capital district has almost the same population as New York.