Turn down the volume on the Washington National Opera's latest foray into zarzuela -- Spanish light opera -- and there are moments when it could be a play by Ibsen or Strindberg as staged by an establishment-minded classical theater company. The costumes are black and white, the set is all clean lines and elegant minimalism, and everything is bathed in a chilly yet creamy Nordic light. The producers of this show have taken Federico Moreno Torroba's three-act operetta "Luisa Fernanda" and classed it up, so much so that the occasional bawdiness of the original feels a little out of place.

But it was the right decision. Placido Domingo, the general director of the Washington National Opera, the greatest tenor of our time, and in this production the baritone lead, is having a genteel argument with the world about works like "Luisa Fernanda." Domingo is the son of zarzuela singers (his mother was famous in the title role of Luisa, and his father sang the role Domingo sings in this production), and he is a partisan for the form. The world demands Domingo, and Domingo insists on zarzuela, and so voila, we have "Luisa Fernanda" at the Kennedy Center Opera House.

Based on the quality and power of works like this, and Amadeo Vives' "Dona Francisquita" (staged at the Washington Opera in 1998), Domingo is making a convincing case. Zarzuela was a parallel Spanish-language musical form that developed alongside Italian opera and flourished as a popular entertainment in Spain in the 1920s and '30s. It is generally silly and comically formulaic, but works such as "Luisa Fernanda," finished in 1932, rise above the rest and make serious musical and dramatic claims.

Or is other people's fluff just more palatable than our own? American musicals don't belong in the opera house, so why does the best of zarzuela? Because it makes demands on the voice that only opera singers can meet, and it is more dramatically ambitious than the product of Broadway -- the ending of "Luisa Fernanda" is painfully open and probably sad. And zarzuela is a popular art form that had the dignity to die before it became truly debased. The sentimentality of the music is charmingly all in the past tense, and its comic gestures never leer, mug or smirk in your face.

The plot is simple: Bad boy loves good girl, who should love the good boy but doesn't, or least not enough to keep herself from going off with the rake in the end. Two forms of love are in play: the sustaining, faithful love, and the desire that gets into your bones in adolescence and keeps messing up your life till the hormones switch off, sometime around retirement. Opera usually pretends that these are the same thing, though there are at least two devastating moments -- one in Wagner's "Die Meistersinger" and another in Strauss's "Der Rosenkavalier" -- when the distinction is made.

Add to those cherished moments the third act of "Luisa Fernanda," when Domingo, who had been making the role of Vidal Hernando a reflection of his own good-humored decency, suddenly went for the emotional jugular. If there's a problem with this production, directed by Emilio Sagi, it's that moments like these are too rare in a staging that generally wafts along on a soft cloud of prettiness. But authenticity like this -- Domingo gives us the primal cry of the nice guy who finishes last -- is rare in opera full stop, so even one instance is well worth the two-hour investment.

"Luisa Fernanda" is also tinged with the political foment of its day, which gives it a tad more ideological gravitas than something by Johann Strauss or Andrew Lloyd Webber. Vidal, a wealthy landowner, is so smitten with Luisa (sung by Maria Jose Montiel) that he will join in revolutionary fighting -- either side will do, because he's not a political guy -- to win her. She sides with the rabble, he follows suit, and the contest for Luisa's love between Vidal and a bounder named Javier becomes increasingly a political contest as well. The opera had its debut during the heady but tumultuous years at the beginning of the Spanish Second Republic (which Franco would trash before the decade was out), and at one moment, the audience's political hopes and fears are directly engaged by the drama. If you're nursing your wounds after the last election, this basic statement of faith in popular idealism will be a balm.

Wisely, the producers of this show (the set is by Paul Taylor, the magnificent costumes by Pepa Ojanguren and the lighting by Joan Sullivan-Genthe) have let the exoticism reside solely in the music. Visually it is stylized and a little sedate. The music, however, is urbane and often melancholy, with lines that are more about simple lyricism than about dazzling sunlight and sequins. Bizet's "Carmen" gets a reference, as does Puccini's "Tosca," and that's clever self-assessment on Torroba's part. His opera falls somewhere in between.

Vocally, Domingo is a colossus. How could he not outshine the rest of the mostly young, mostly appealing cast? Even in a baritone role, when he opens his mouth, you hear that distinctive Domingo sound, the heroic timbre with the touch of genuine vulnerability. It's as if Wagner's Tristan has given up his gloomy castles and tempestuous northern seas to toss off a few southern tunes with the singing waiters (which is almost literally true: Domingo is preparing to record Tristan later this year, perhaps his greatest challenge and, one hopes, his most impressive accomplishment).

It was hard not to hear and pine for the sound of Domingo in the role of Javier (he's recorded it), which was sung by Israel Lozano, a much younger Spanish tenor. Lozano's voice is smaller and lighter than Domingo's and not yet fully fledged in the top notes. But he looks the part, and he wins the day with unaffected musicality.

The women in this production are uniformly well cast as well. As Luisa, Montiel wields a mezzo-soprano voice that is compact but warm, and she found a sympathetic earnestness in a role that could easily come off as flighty and manipulative. The Duchess Carolina, the rich, saucy foil to Montiel's Luisa, was sung by Spanish soprano Elena de la Merced with a voice that makes up with flexibility and clarity what it lacks in color.

Musically, from everyone but Domingo, and including the orchestra, chorus and other cast members, one wanted just a bit more of something. Rhythmic vitality? Characterization? Volume? Perhaps this is to be laid at the feet of conductor Miguel Roa, whose overall shaping of the work left the sense of being just a bit too cool and suave, and slightly remote. Torroba's music isn't as flashy as Vives' "Dona Francisquita," and it will never be as sexy. But there are pivotal scenes -- the confrontation between Luisa and Javier, for instance -- which needed more menace and energy.

Then again, music that is new to an audience -- and a critic -- often feels fainter in performance than it really is. A tighter, edgier interpretation might make "Luisa Fernanda" all the more vivid, or perhaps just vulgar.

The bigger question -- for Domingo and his fans -- is whether without him, works like this will make inroads into the international opera canon. It's not hard to like "Luisa Fernanda," but is it worth the effort to get to love it? Opera lovers outside of Spain are in much the same position as Luisa herself.

Smitten early with the familiar features of the volatile Italians and the dark, inward Germans, can you learn late in life to love the simple charms of the Spanish? Art, like life, is a test of just how promiscuous we can be with things like curiosity and affection. For those who like to stray a little, "Luisa Fernanda" is highly recommended.

Luisa Fernanda will be repeated Tuesday, Friday and Nov. 14, 15, 17 and 19. Call 202-295-2400 or visit www.dc-opera.org.

Placido Domingo and Maria Jose Montiel in Washington National Opera's suave zarzuela.Spanish soprano Elena de la Merced and tenor Israel Lozano in the Washington National Opera's production of the zarzuela "Luisa Fernanda."