EVITA, by Tim Rice and Andrew Lloyd Webber; directed by Harold Prince; choreography, Larry Fuller; sets and costumes, Timothy O'Brien and Tazeena Firth; lighting, David Hersey; orchestrations, Hershy Kay and Andrew Lloyd Webber; sound, Abe Jacob. With Valerie Perri, Anthony Crivello, Robb Alton, Peter Marinos, Jamie Dawn Gangi.

At the National Theatre until Nov. 29.

"Evita," the much-decorated musical by Tim Rice and Andrew Lloyd Webber which opened last night at the National Theatre, possesses an abundance of theatrical virtues. It has epic sweep, cool cynicism and the sulfurous excitement of a political rally that threatens at any moment to verge on mass hysteria.

But its keenest virtue -- the one that throws all the others into relief -- is the double-mindedness with which it approaches its title character.

Evita, lest you have missed out on several years of hype, is Eva Duarte, a scrappy refugee from the middle classes who, before she died of cancer at age 33, fought her way from provincial anonymity to fame as an actress, and then near-sainthood as the wife of the Argentine strongman, Juan Pero'n. Was she nothing more than a bejeweled extension of tyranny, who hid her ruthlessness with an artful makeup job? Or did the radiance of her smile and the audacity of her ambition actually put hope and comfort into the lives of Argentina's downtrodden?

With uncanny expertise, "Evita" advances both views of the woman simultaneously. Saint and sinner are one, and if the saint shines through the sinner on occasion, the sinner also bleeds through the saint. By extending the duality in Eva's soul to the rampant spectacle of her life, the creators of "Evita" have come up with more than a lavish musical biography. They have given us a veritable picture-book of power.

Like "Jesus Christ Superstar" and "Joseph and the Amazing Technicolor Dreamcoat," "Evita" is made up entirely of musical numbers. Webber's songs, ranging from the graceful to the fiery, are stronger than Rice's lyrics, which are often bland and simple-minded. On its own terms, however, the score is considerably less dramatic than the show as a whole. The impact of "Evita" is directly traceable to director Harold Prince's remarkable staging, which actually goads the songs to life, forces them to take arresting stances and amplifies their sentiments.

In his heart, I suspect, Prince is a disciple of Brecht. That is to say, he favors a hard-edged approach that puts distance between the spectacle and the spectator. Not for him the warm, moist musical that hugs an audience to its breast. With choreographer Larry Fuller, he has created a dazzling array of theatrical metaphors that illustrate the drama in stark nonrealistic terms.

In "The Art of the Possible," for example, Pero'n's irresistible rise to power unfolds as a game of musical rocking chairs. Eva's equally abrupt rise through the bedrooms of Buenos Aires is depicted solely with a revolving door, a parade of lovers and her increasingly luxurious wardrobe. And Argentine high society, never disposed to embrace the upstart Eva, is a clutch of snobs, seemingly glued together, diamond bracelet to ebony cigarette holder, moving across the stage as a single unit.

The images are volatile, ever-changing, and nearly always keep the production in a state of tension. Prince even dares to vie with himself by pitting on-stage events against grainy newsreel footage. It makes for a bastard mix, perhaps, but the staging imparts a very real sense of history in the making.

Riding an advance of more than $1.4 million, "Evita" gives every sign that it will stay well beyond its announced Nov. 29 closing date. Politics is only the obvious lure here. Show business, politics' first cousin, exerts nearly as strong a claim on this city. And Eva belonged to both worlds. She was, in fact, the very embodiment of the actress as politician.

Of course, the show recognizes the possibility that Eva may just have been a glittering fraud who used her kinship with the common folk, the "descamisados," to feather her nest, not to mention her hats. "Do you now represent anyone's cause but your own?" sings Che' Guevara, spitting the syllables at her like lead pellets. In one of the show's deviations from historical accuracy, Che' functions as the evening's narrator and general gadfly. Sometimes hovering on the fringes of the action, sometimes blazing through it like an avenging angel, he questions Eva's motives every step of the way.

So does the musical. Indeed, Prince, operating at the peak of his craft, has fused a big question mark into the production, as if with a blowtorch. But if Che' already has his answer -- for him Eva is opportunism incarnate -- the show allows for other possibilities.

Taking stock of herself early on, Eva admits to "just a little touch of star quality." The admission reeks of understatement. Eva's very function in life and politics was glamor. In the face of the blinding poverty of her countrymen, she resolved to live out their wildest dreams of luxury and beauty. For them, she said. "She's a diamond in their dull, gray lives," exults Pero'n with the smugness of one who can afford diamonds.

A dark-haired mongrel at first, Eva soon becomes as sleek as a greyhound and as blond as the sun. In one of the musical's most stunning scenes, she boldly takes her new self to the people. Perched on a balcony, she pleads "Don't Cry for Me, Argentina," assuring the adoring throng below that, appearances notwithstanding, she has not abandoned them. The haunting melody does not entirely cover the mordant irony of the moment. Just as her tears start to flow, Prince flips the perspective 180 degrees. Suddenly we are behind Eva, looking out at the crowd and privy to the cold calculation that is going into her warm appeal.

It is this very artifice that intrigues Prince and his collaborators. Every great performance is made up of strategems, lies and even a few crocodile tears, and Eva was nothing if not a great performer. History, in its moral moments, has its own way of passing judgments; the theater goes by a different yardstick. The very qualities with which Eva took on the world -- drive, panache and even duplicity -- are those qualities that command a stage and force a kind of admiration that transcends morality.

As a result, Che' can scorn her as "the instant queen," call her sluttish names and shoot an acrid cloud of cigar smoke in her direction, but he never succeeds in bringing her down. Even a face-to-face confrontation, "Waltz for Eva and Che'," is a draw -- his firebrand passion checked in its tracks by her flippant superiority.

In most respects, the cast is up to the demands Prince has imposed upon it. Granted, Valerie Perri doesn't quite have the triumphant vulgarity of Patti Lupone, who won a Tony for her portrayal of Evita, and her voice doesn't bite into the air as Lupone's does. Still, Perri has a fine-boned elegance that makes Eva's hold on the populace eminently comprehensible. In the final moments when, ashen with fatigue and devoured by cancer, she fights her way to the microphone for a final appeal to the people, Perri displays a gut courage that almost single-handedly redeems Eva for all the accumulated sham.

Robb Alton emphasizes the pastiness of Pero'n, playing him as a brilliantined mediocrity. The marriage of cowardice and false modesty, as he lurks just beyond Eva's glow, is deft indeed. Unfortunately, Jamie Dawn Gangi makes nothing of her role as one of Pero'n's cast-off mistresses (neither does the show, it should be pointed out), but Peter Marinos is properly slick as the two-bit entertainer who was Eva's first steppingstone to the big time.

The most arresting performance, however, is that of Anthony Crivello, as Che'. Part guerrilla, part Groucho, the actor buzzes over the stage like a mad hornet. Yet the fulminations of rage never denature his voice, which has the limpidity of a crystal dagger. Crivello has also found something new in the part, or something I'd never noticed before: Che''s love for Evita.

It is begrudging and it goes against his every instinct. It is there, nonetheless, and it enhances the ambivalence at the core of the musical. Whatever her sins, after all, Eva was a woman who wore her destiny like a fur coat, slung defiantly over her shoulders. Neither Che' in his fury nor the fickle appraisals of posterity can divest her of that. And destiny, as "Evita" illustrates brilliantly, is a most seductive raiment.