WILLIE STARK, libretto and music by Carlisle Floyd, based on the novel "All the King's Men" by Robert Penn Warren; directed by Hal Prince; scenery by Eugene Lee; costumes by Judith Dolan; lighting by Ken Billington; conducted by John DeMain and Hal France; with Timothy Nolen, Jan Curtis, Alan Kays, Don Garrard, Julie Conwell, Robert Moulson and the voice of Lowell Thomas. At the Kennedy Center Opera House through May 29.

It was hard not to be apprehensive about "Willie Stark," which opened at the Opera House Saturday night. Nine years had passed since the Kennedy Center commissioned the work and the same man, Carlisle Floyd, was acting as both composer and librettist. After abandoning an original take about a mythical southern governor, he had begun anew with the southern governor to end all southern governors -- Huey Long, alias Willie Stark, from Robert Penn Warren's much-honored novel "All the King's Men."

How could such a sprawling story not be trivialized on the musical stage? And then again, wouldn't the subject of proto-fascism in America seem like yesterday's news in a political era more preoccupied with ineffectuality than totalitarianism?

Against all these grounds for alarm, "Willie Stark" is first a great relief and then an impressive, if flawed, piece of work. Floyd has recombined the key elements of the novel into a lean and well-told story, focusing on a manageable core of central characters. The three principal roles are brilliantly cast and played, and the whole enterprise has been staged with epic precision by Hal Prince, in a stunning and evocative visual collaboration with designer Eugene Lee.

For Prince -- not to mention the audience -- this could have been a tired recycle of "Evita," another opeatic tale of a national leader winning the blind trust of the people. But both Floyd and Rpince have taken a different approach this time. While "Evita" is about a whole nation and about the dynamics of the love affair between a leader and her people, "Willie Stark" is about the man himself, about the faithful coterie around him, and about leadership, compassion, ambition and corruption. And in contrast to Robert Rossen's movie version -- which made Stark cruder and less attractive than in the novel -- Floyd has raised Stark back to his full intriguing stature.

Besides discarding and compressing vast parts of the novel, Floyd has taken one bold and shrewd liberty. He has combined the character of Jack Burden, Stark's aide and the book's narrator, with Adam Stanton, Stark's assassin. He has made this new version of Jack into an upper-crust idealist whose fiance is having an affair with Stark, creating a new romantic triangle. When the call for Stark's impeachment is sounded and Willie sets out to find something incriminating about Jack's father, his archnemeses, the mechanics of tragedy start turning at high torque.

It's quite a surprise, and a pleasant one, that a writer of operas should prove so adroit a plot maker. But somewhere between that skill and Floyd's obvious ability as a composer, this large work betrays what may be a gap in the author's unusual virtuosity. There are times when "Willie Stark" cries out for a song you can sink your teeth into, and simply fails to deliver. Even when a single character signs a sustained passage on a single subject, the lyrics and melodies seem discursive and fragmented (which aggravates the inevitable trial of merely understanding the words, no less interpreting them).

When Willie finally confronts Jack's father, he delivers a musical lecture on the law as a "single bed blanket." "Yeah, Judge," he sings, "I stretch the law, I pull on it hard, 'cause I know what it's like to be cold." The words are strong and suggestive, but prosaic, and the music follows suit. Perhaps this has something to do with "Willie Stark" being called a "musical drama" rather than simply a "musical" or an "opera." But on the working theory that all these forms can be judge by a common standard, I'd say that Floyd fails to give his themes sufficiently distinct musical identities. The music seems, too often, like an afterthought, and it is easy to imagine some of the lyrics faring better as plain dialogue.

But Timothy Nolen, Jan Curtis and Alan Kays give performances that add up to a powerful case for Floyd's text. Nolen sings the title role with vigor, charm and innate plausibility, bringing the first act to a rousing end as he mobilizes his legions with a spech-in-song. Curtis is ferociously memorable as the posessive Sadie -- even her hair shakes when she teaches Willie the value of fiery oratory in "Shake 'Em Up" (although this is one of those occasions when more meter and melody might have been apt). And Kays gives an affecting portrayal of Jack's disintegration from clean-cut poise at the start to physical and mental disarray at the finish.

Speaking of finishes, "Willie Stark" offers new evidence that no one can bring a curtain down like Hal Prince. He has created plenty of strong visual images on the pseudo-marble majesty of Eugene Lee's scenery, but he has saved his best for the end -- when Willie is shot down on the steps of the State Capitol, the building flies away, and Willie's chauffeur/bodyguard carries the corpse up the white steps and into the heavens. At times like these -- and "Willie Stark" offers quite a few of them -- the limitations of the work seem immaterial, and the moment seems eternal.