Back in 2004, when a thousand anti-Bush flicks bloomed, Republicans and their fellow travelers expressed shock that documentaries might have a point of view. Well, of course they do, and that’s never really been in dispute. It’s just that most documentaries express opinions that are safely mainstream or address topics of distant relevance. Thus of the three nonfiction (or semi-nonfiction) films opening this week, the one with the most radical outlook is Overlord, which finds no glory in D-Day. And the one of least pertinence is Sketches of Frank Gehry, which supposes that the hottest architect of 1997 is an artist for the ages. But the one that will be mostly widely condemned as polemical is An Inconvenient Truth, which dares question U.S. automotive-fuel-efficiency standards—and in the process positions Al Gore for another presidential campaign.

Essentially an illustrated lecture—or, if you prefer, a concert film—An Inconvenient Truth follows Gore around the world as he revalidates the environmentalist credentials he put into a blind trust during his eight years as veep to business-as-usual Bill Clinton. Director Davis Guggenheim tracks Gore ducking down hotel corridors, dashing through airports, and riding in a variety of gas guzzlers. (The film promises that its fuel use was “offset by Native Energy,” but Gore’s own lifestyle certainly doesn’t look carbon-neutral.) These cinéma-sorta-vérité sequences merely punctuate the main event, which is Gore’s presentation on global warming. Personalized with family anecdotes and sweetened with cartoon critters, the show is entertaining, even if it’s not entirely convincing.

Gore’s computer graphics are impressive, and he interacts with them skillfully. He shows graphs and heat maps that posit a quickly warming Earth, as well as simulations of what will happen if large chunks of Greenland and Antarctica melt: Manhattan will be very soggy, Shanghai will be inundated, and Bangladesh will be essentially gone. But the emotional peak comes during a bit on the old parable of how a frog will jump from a pot of boiling water but stay in one whose water gradually warms to boiling. (For the record: This is not true.) The cute animated amphibian is us, of course, sitting cluelessly in a world that’s becoming fatally overheated. What should we do? asks Gore. “Well, first you rescue the frog,” he suggests, and the ’toon is plucked from the water. You can almost hear the entirety of the Little Mermaid generation breathe a sigh of relief.

This sequence carries the essential message of An Inconvenient Truth: Gore is back, and now he has a mission and a sense of humor—and cartoons! He sounds more like Mister Rogers than ever, which won’t win over voters who prefer their presidential candidates to bark like Rambo. Yet despite a first-rate environmental-horror slide show, including a clip from Futurama, Gore still relies on such old campaign standards as his sister’s cancer death and his son’s car-crash near-death. Neither has as much to do with global warming as with personalizing Gore, a man who may look detached but wants you to know he’s suffered just like people who didn’t grow up living in the Fairfax Hotel.

That’s one trick Gore learned from the political consultants long ago. Another is staying on message, which is why his environmentalism is all about global warming. It’s no surprise that Hurricane Katrina plays a big role in Gore’s presentation: It’s big, it’s new, and it makes Bush look like an asshole. But even if warmer seas did intensify Katrina, the hurricane was a disaster primarily because of a separate issue, the unchecked incompetence of the Army Corps of Engineers. If the Mississippi had never been channelized and New Orleans not surrounded by improperly designed and built levees, the storm would have done much less damage. There’s a similar problem with Gore’s critique of American cars. Yes, it’s striking that the United States has lower mileage standards than any other major auto producer—including China—but even zero-emission vehicles would be an environmental debacle because of their effect on land-use policies.

Perhaps Gore is, as he claims, not running for president. Maybe An Inconvenient Truth really is a deeply felt response to a crisis that Gore has contemplated—as he says here—since a college course with early global-warming theorist Roger Revelle. And maybe it will inspire a few people to trade in their SUVs. But the inconvenient truth is that this film is likely to do more for Gore’s political profile than for the soon-to-be-submerged residents of West Bengal.