In his latest docu-indictment, Michael Moore again proves himself master of a genre we could call polemical entertainment. And both words carry equal weight: Moore brandishes his agenda--an attack on America's health-insurance system--like a saber, yet he also avoids hectoring, and turns potentially dry material into a film that's funny, poignant, and a call to arms. When's the last time you learned something that made you want to mount the barricades? Not surprisingly, in Cannes (which awarded Moore the Palme d'Or in 2004 for Fahrenheit 9/11) Sicko had 'em cheering in the aisles.

Unlike Moore's previous broadsides, Sicko focuses more on the message than on the portly messenger delivering it--in fact, Moore mainly appears on screen in the now-notorious Cuban finale. It's bad enough, he states at the outset, that 50 million Americans are without health insurance, but this film takes up the cause of those with health insurance who are still getting screwed. Make the mistake of falling ill in America, and you're likely to get bankrupted, Moore maintains. The villains, no surprise, are the insurance companies (and as this film gains traction, their CEOs might consider adding more locks to their gated communities). In a typically lively sequence, the Star Wars theme blasts from the soundtrack as a list of maladies for which companies deny coverage scrolls down the screen. Bottom line, the insurance companies are about the bottom line, denying coverage in order to maximize profits. In one outfit, an employee with the highest number of denials actually received a bonus.

Ever careful to sugarcoat the instructional pill, Moore lays out a history of health care, starting with Nixon. Under Reagan, the U.S. slipped--and the figures are telling--to #37 in health care around the world. Hillary Clinton initially gets plaudits for her original health-care plan, which "the AMA attacked as socialized medicine." But now, says Moore, hefty contributions have made not only Clinton beholden to Big Pharma--the insurance biz has "bought Congress." Moore balances facts and figures with the horror stories of ordinary folks; insurers told a guy who severed two fingers that they'd pay to restore only one (a uxorious husband, he chose the ring finger), while a woman loses her husband because he was denied life-saving medication.

In its second half, the film contrasts countries with health care--Canada, France, Great Britain--that actually benefits its citizens. A discharged patient approaches a cashier's window in a British hospital-not to pay a bill, but to receive payment for the cab ride home; in France, house calls are free and new mothers get help with the laundry.

Moore also slyly shows that doctors in these societies make good money. In the stirring--and intentionally outrageous--wind-up, Moore takes boatloads of rescue workers who've fallen ill after 9/11 to Cuba, an economically struggling country, for the medical care denied them at home. The warmth between the American workers and their Cuban counterparts is especially affecting.

Yes, the film runs a bit long and the hard-luck stories turn repetitious. And of course, Moore can be accused of idealizing and oversimplifying the state-run systems in Canada and France. But as he insisted in a press conference in Cannes, he's not a scholar--he's a filmmaker with an imperative to entertain. There's more to it, though. In Sicko, Moore is reaching beyond his usual base of informed fans to a wider constituency: all Americans sickened, figuratively and literally, by managed care. Simpler is better, in his view. Moore wants not only to take the profit motive out of medicine--he aspires to actually effect change through film. Mocking the fear of "socialized medicine," he weaves in material unlikely to please defenders of the status quo, such as the fact that the top one percent of the world's population has 80% of the world's wealth. After a scene showing how hospitals in America dump the indigent in the street, Moore poses the question, "Who are we?" Sicko calls for a society that focuses on "we," not just "me." That Moore can make such a film is a testament to this country's freedoms.