The vocal miracle that is Placido Domingo cannot, I fear, go on indefinitely, and so anybody interested in the art of opera should make a point of listening to him whenever, wherever and whatever he sings. At the age of 64, Domingo continues to "have it all" -- a tenor voice of noble dimensions, clarion power and astonishing freshness; supreme musical and dramatic intelligence; and a stage persona that exudes both heroic magnetism and easy charm.

Domingo is in town right now, wearing one of his multiple hats as the general director of the Washington National Opera, and singing in his own revue, "Trilogy: Domingo and Guests in Three Acts," which opened Saturday night at the Kennedy Center.

"Trilogy" consists of Act 2 of Umberto Giordano's "Fedora," Act 4 of Giuseppe Verdi's last great tragedy, "Otello," and a lighthearted, radically rearranged Act 3 from Franz Lehar's "The Merry Widow," transformed into a platform for showpieces and a few one-liners. It's the sort of program that tends to drive audiences wild and critics a little bit crazy, leading, as it does, to an inevitable question -- why do other cities get to hear Domingo in the masterpieces of the operatic repertoire while Washington has to get by with performances of zarzuela, a sort of Spanish Gilbert and Sullivan (Domingo sang "Luisa Fernanda" here last year), and now this celestial vaudeville?

That question posed (and left unanswered), the selection from "Otello" may be the finest single act I've ever heard from the Washington National Opera -- amazing music, without a wasted note, conducted with a mixture of epic sweep and moment-to-moment tenderness by the company's superb music director, Heinz Fricke.

Barbara Frittoli was a lovely, volatile Desdemona, wistful and distracted in the "Willow Song," movingly devout in the "Ave Maria" (interrupted on Saturday night by some chowderheads in the audience who decided to bellow their approval before the aria was over) -- purest innocence, slimed and slaughtered. As Samuel Johnson famously wrote of Desdemona's murder in Shakespeare's tragedy, it is simply "not to be endured"; even after some 40 years of exposure to this opera, I found myself thinking vainly of ways to effect her last-minute rescue.

Domingo was appropriately unhinged throughout his 15 minutes on the stage -- suppressed animal fury, a violent release and then futile and agonized remorse. There was a palpable heaviness to his death scene: One felt Otello's ruined sorrow growing ever more burdensome until he finally dropped to the floor and the music came to an exhausted end. There was limpid support from Erin Elizabeth Smith as Emilia.

Nobody will ever mistake "Fedora" for "Otello," nor Giordano for Verdi. And yet I always find myself surprised by the subtlety and originality of this score, which is on a much higher level than the typical late-19th-century Italian bodice-ripper, with some unusual orchestra effects and a long passage accompanied only by piano. It's too bad that the grand moment for tenor -- "Amor ti vieta" -- lasts only about a minute and a half (perhaps the shortest bravura aria in the repertoire?) but Domingo gave it full sun-splashed ardor. Sylvie Valayre was a fetching, multi-dimensional Fedora, soaring and searing by turn in a flashing variety of mood: She would seem to be a major talent. Eugene Kohn led the Washington Opera Orchestra and Chorus with winning energy but not much command of balance between the stage and the pit: The singers were regularly drowned out.

After an intermission that went on at infinite, unexplained length, "The Merry Widow" closed the evening, with some blithe, stratospheric chirping from Broadway star Christiane Noll (Gershwin's "By Strauss!"), an agreeably sentimental "Merry Widow Waltz" crooned by Domingo in a lighter voice than he had hitherto displayed, a faux-naughty cancan, and a plethora of nudge-nudge wink-wink silliness. Funniest moment of the night -- Domingo and Frittoli (Otello and Desdemona), back in evening clothes, meeting at a party, with Domingo's sheepish opening line: "Signora, you are looking a lot better!"

"Trilogy" will be repeated on Tuesday, Friday and Oct. 2, 6 and 9.

Placido Domingo in the "Merry Widow" segment of the Washington National Opera production of "Trilogy: Domingo and Guests in Three Acts."Placido Domingo with Sylvie Valayre, who sings the title role in the "Fedora" segment of the Washington National Opera's "Trilogy."