Film prefers a simple story, but in politics all is nuance. And the greatest political figures, at least from a dramatic standpoint, are great both in good and evil. What distinguishes "Huey Long," Ken Burns' masterful documentary on the Louisiana Depression-era populist, is the way it embraces both the good and evil and the man -- it's extraordinarily large-spirited.

As the movie suggests, Long was an enigma in American politics: a champion of the power of the people who amassed untold power in himself, a self-styled democrat who scorned (and worked to destroy) democratic institutions.

He was a bully who didn't balk at ruining families when it served his political purpose, and he never lacked an unkind word, but from a distance, at least, he was a lovable rogue, and "Huey Long" capitalizes on that. A squat, lumpy man with Howdy Doody ears and a great cowsk,1 sw,-1 catcher grin, Long was a master orator, bull-voiced, who framed current events in visual and dramatic terms people could understand.

One of his favorite stump tricks was to ask how many in the audience owned four suits. No hands were raised. Three -- none again. Two -- none. Then, with the umbrage of Moses, Long would declaim that J.P. Morgan owned one hundred suits. As "Huey Long" wryly notes, Long himself, a notorious dandy given to orchid shirts, bizarre floral ties and spats, owned more than one hundred suits himself.

Yet Long was no garden-variety hypocrite, and the theme of that parable -- that the rich should share the wealth -- was not just a demogogue's trickery. When he became a potent figure on the national scene, Long's ideas on the redistribution of wealth remained vague and half-formed. But during his tenure as the governor of Louisiana, he did redistribute the wealth, and though much of the wealth was redistributed into his own pocket (into the famous "dee-duct box"), much more went to the roads, bridges, free textbooks, night schools and hospitals that brought Louisiana out of the Middle Ages.

Part of Burns' purpose is simply to create a sense of balance; the movie consists largely of interviews with contemporaries of Long's, and Burns quotes equally from both sides. The witnesses include Mrs. Hodding Carter Jr., whose husband editorialized regularly against Long (and who reports that hardly a night went by without someone suggesting the Kingfish be killed); Huey's son, Sen. Russell Long; and most notably, poet Robert Penn Warren, whose prize-winning novel, "All the King's Men," drew on Long for its inspiration.

Warren nearly steals the show -- his cheeks sunken, his eyes unfocused, he is all voice, final and imperious, moving from a growl to the whistle of a big wind, obedient to explosive rhythms that are wholly his own. Whenever Warren talks, time stands still, whether he is reading from his novel (excerpts from which frame the movie) or recounting stories about Huey or what Huey meant to him.

Warren seizes your attention, but otherwise, Burns is careful to weave the interviews into the narrative -- everything in "Huey Long" is put at the service of the story. The narration (spoken by the appropriately reticent, gentle-voiced historian, David McCullough) is lucid and eloquent, in a way, without being flashy. And Burns is a master at wedding images to the words, a task that is much harder than it seems (you'd only notice it if it's wrong).

Old photographs flow together till they appear to be movies, too; and music -- mostly bluegrass and New Orleans jazz -- is masterfully included to create an overall mood, to bind the images. Newsreel excerpts aren't allowed to sit alone, but are carefully introduced and picked up at the end. On a technical level, "Huey Long" is historical documentary-making at its most accomplished.

What's significant about the interviews, though, is not simply the appearance of balance, but a much subtler dynamic, dependent on who's saying it, and what they're saying. For the most part, Long's adherents are poor people: ignorant Cajuns, sharecroppers, the kind of people Long grew up with in Winn parish, where they "produced only one crop in abundance: dissent."

Carter, on the other hand, appears in a lovely silk blouse on a brocade sofa. Journalist I.F. Stone appears in similarly comfortable surroundings and talks with erudition about Caesar. The sharpest constrast is made by Roosevelt-era historian Arthur Schlesinger Jr.,, wearing a bow tie like a bedspread, sniffing donnishly about Long's unsound methods.

Burns isn't making a facile division between a man of the people and the intellectual mandarins; what he's saying is much larger, and more tragic -- he's saying that both are right. As Warren notes, it's the age-old struggle between power and ethics. Columnist Tom Wicker, in a charmingly offhand way, puts his finger on the movie's theme when he says that Long "came to the realization that you cannot do the good that you wanted to do . . . in a democracy." At which point, "Huey Long" becomes a movie, not about good versus evil, but about the evil that grows from good, and touches a moment that is almost Shakespearean. Huey Long, opening today at the Key, contains no offensive material.