An incisive, provocative documentary on the new leftist leaders emerging in South America would be a real service, but Oliver Stone’s “South of the Border” is frankly more puff piece than solid journalism, a picture that squanders its potential by preferring softballs to hard pitches.

Stone travels to various South American countries, and finally to Cuba, for sessions with figures who are often portrayed simply as anti-US dictators but whose ideas are clearly more complex than that label would indicate. His first, and longest, stop is in Venezuela, where he talks with Hugo Chavez, the Bush administration’s chief villain in the region (post-Fidel, of course), surrounding the excerpts from their conversation with a mini-biography using archival footage. The tone is resolutely positive, with Chavez portrayed not as the dark socialist threat of right-wing commentators but as a populist fighting to help his impoverished countrymen in the face of American financial interests promoted by such entities as the World Bank (and US governmental efforts to undermine, even overthrow, him). Film of Chavez visiting his simple childhood home, interacting with plain folk, and even riding a bike (and breaking it in the process) are also meant to identify him as a man of the people, courageously fighting the oppressive elites.

There’s actually some truth to all this, but Stone’s presentation is as one-sided as the Bush-Cheney line on Chavez. One could argue that that merely redresses the imbalance, but what would be better still is a more objective portrait that shows both the virtues and the flaws.

The coverage of Venezuela is by far the most extensive here, but Stone visits with other “new” leaders as well—Bolivia’s Evo Morales, Argentina’s Nestor Kirchner and his wife and successor Cristina, Paraguay’s Fernando Lugo, Ecuador’s Rafael Correa, and Brazil’s Luiz Inacio Lula da Silva. He portrays them all as representing a diverse but unified movement of Bolivarism, the “new socialism” that Chavez identifies with the thought of the great nineteenth-century South American liberator. And he connects it with an earlier progressive revolution by adding a brief interview with Raul Castro.

Some of the subjects actually say interesting and insightful things, but Stone never challenges them, and as a result the documentary comes across as more propagandistic than enlightening, though the historical narration he recounts (co-written by Tariq Ali, who also contributes some talking-head commentary) is restrained and solid. One certainly can’t deny the long history of US intervention in Latin and South America, or the problem of prescribing nothing but unfettered free market capitalism as the antidote to endemic poverty and class division in the region. But the issues deserve a more serious treatment than the sound-bite one this film offers. (At least Cristina Kirchner takes Stone to task when he asks her how many pairs of shoes she’s got.)

So “South of the Border” is an opportunity that Stone has unfortunately squandered, and the loss is ours. But at least it gives you the chance to hear these new “Bolivarian” leaders unfiltered by the American media.