George Gershwin labeled "Porgy and Bess" a folk opera, which may have been a way of describing a work that rightfully belongs in a category of its own, one that is neither opera nor musical theater. The production that opened last night at the Kennedy Center takes Gershwin at his word that the work is an opera, and reveals a magnificence of music at the expense of some of the emotional values.

The production is lavish in almost every respect: vast, towering sets creating the impoverished ghetto of Catfish Row in Charleston, S.C., and the nearby Kittiwah Island; large numbers of performers onstage and a company allowing four singers to alternate in the demanding role of Porgy and three in the role of Bess. The intention was not merely to restore the original but to surpass it, and to advance it into the ranks of opera from its position as a giant American musical.

But the question also can be asked: is the show best served by this reverential treatment? Does the operatic mode allow the drama of a group of poor, southern black people to touch our hearts as piercingly as it might?

The conflict between style and content is exemplified by the character of the drug dealer, Sportin' Life. Larry Marshall, who plays him here--this role is the only one not multiple cast--has a background in both musical theater ("Hair") and more serious music ("Mass") and has the ability to meld music, dance and a sharply defined character seamlessly. He is the least operatic of the company and the most vivid as a character.

This is not to say the other performances are not good--they are, and as Porgy, Michael V. Smartt (who played the part in the Wednesday night preview) has moments of greatness, particularly during the heartbreaking "Oh, Bess, Oh, Where's My Bess." They are all superb singers, but the characters are too often stereotypes, the words lost in the trajectory of highly trained sound, and the soul diluted by awkward staging.

At one point during "Bess, You Is My Woman Now," for example, Bess (Henrietta Elizabeth Davis on Wednesday) slowly sinks to her knees and starts across the stage to her new lover, the cripple Porgy. It is a highly poignant moment of supplication and devotion as he reaches out to her from his perch on the small, wheeled platform that he uses to move around. But then Porgy jars the moment with a quick scoot toward her.

Curiously, the formality of the operatic treatment seems to underscore the archaic portrayal of blacks in this show. In 1935, a show about black people who sang things like "Oh, De Lawd Shake De Heavens," and who were superstitious and given to killing each other over dice games and women was not considered racist. Allowing them to feel heartbreak and despair was presumably an advance over the then-typical Happy Darkie cliche'. But a 1983 revival, no matter how faithful, could be more sensitive by avoiding the stereotypes of eye-rolling and corny dialect without abandoning the authors' intent.

In the context of an opera the denizens of Catfish Row become more exotic and less folk, isolated by theatrical conventions that somehow legitimize the isolation created by racism. It's a thorny problem and one not easily solved.

The story certainly provides ample operatic fodder with three tragic deaths, a revenge killing, a life-threatening hurricane (this production has such wonderfully convincing thunder I started to wonder if my car windows were closed) and a heart-rending love story.

The people of Catfish Row have a community that is buffeted by poverty and violence but sustained by love and religion. Porgy lives by begging and shooting craps; he has "plenty of nuttin' " but isn't really happy until Bess, seeking his protection when her lover Crown kills a man and flees, becomes "his woman." But Bess has moral fiber that dissolves with one snort of cocaine. When temptation beckons, in the form of Sportin' Life with drugs or Crown with sex, she has the decency to hesitate, but only for about 10 seconds. Porgy kills Crown, but Bess, plied with drugs, weakens and leaves for New York with Sportin' Life.

Meanwhile the neighbors have buried Serena's husband, killed by Crown, and a loving young couple, Clara and Jake, who are victims of the hurricane. The vignettes of daily life complete the story: a funeral, a fast-talking lawyer selling Porgy a divorce (Bess' from Crown) for $1.50, a community picnic.

The music is as fabulous as ever, a score that ranges from foot-tapping jazz to soaring arias with amazing versatility. And anyone who isn't weeping during the next-to-last scene, when Porgy discovers that Bess has left him, probably can peel onions without even blinking.

This production, a revival of the 1976 Houston Opera production, runs through June 18.