Lotte Lenya shines brightest as the keeper of the flame.Indeed, to borrow a phrase from her famous "September Song," it is she, the singing actress, who made that flame of the iridescent leaves of Kurt Weill's music.

The flame, much like the raw colors and hurled forms of German Expressionist painting, brought a new and angry intensity to art. It also illuminated an era of a failed political but incredibly successful cultural revolution: Berlin in the '20s.

The talent and creativity of that eruption keeps haunting the American mind. What happened in the art and film studios, in the concert halls and on the stages of Germany between the Kaiser and Hitler has profoundly influenced American culture. A recent evening of Kurt Weill's music, performed under the auspices of the National Museum of American Art, is further evidence. It brought Lotte Lenya to Washington.

Chain-smoking, Lotte Lenya talked with the clarity, impulse and buoyancy of a mountain brook. Every pebble beneath the flow of her talk was in view.

She was born on Oct. 18, 1900, in Hitzing, a working-class district of Vienna, and an Austrain intonation still mellows the timbre of her voice.

Her father was a coachman, her mother a laundress, and her working-class dignity is still her predominant trait.

It is part of that trait that Lenya does not look old. She never had beauty that could fade. Plain is plain and years cannot alter that. Lenya's face, to judge from the famous photographs, has only become more endearing. Someone once said that her face is "like a clock without a second hand." That's Dada.Her face is not like any thing. it is a face Kaethe Kollwitz might have created. It is, like Lenya's art, Expressionist.

As a child, she played in one of those pathetic neighborhood circuses doing a tightrope act with an umbrella. During World War i, she lived with an aunt in Zurich, learning ballet at the Stadttheater. When the war was over and the Kaiser had fled, Berlin was suddenly the magnet for rebellious young artists.

Lenya landed bit parts in Moliere and Frank Wedekind's "Fruehlingser-wachen" ("Spring's wakening") there. She soon met, lived with and married a short, pudgy, balding composer with thick eyeglasses named Kurt Weill. He was 24 at the time, studying with Ferrucio Busoni.

"Everybody was so incredibly young," said Lenya. Weill, for instance, had already written a respectable oeuvre, including a symphony. Hindemith was a "Herr Professor" and head of the Academy of Music at 32.

"All these questions, all this analyzing!" she said. "We had fun. I guess fun does not fit into art historical theory."

They had fun overthrowing conventional concepts in art and architecture which had become too rigid to be fertile. And when Kurt Weill, Lotte Lenya and Bertolt Brecht, in 1927, went to the modern music festival in Baden-Baden, the ritzy spa, they had fun overthrowing conventional concepts of opera with their first version of "Mahagonny."

"From the ordinary, [Mozart] created legends, and from legends I created the ordinary," Peter Shaffer has Antonio Salieri say in his superb new play, "Amadeus." Kurt Weill and Bert Brecht used the ordinary to give voice to an artistic expression of protest. They chose opera, the most bourgeois and most refined art form of them all, to turn their crude proletarians into heroic legends. It took an ordinary, an untrained, a defiantly un-operatic voice to make the point that even opera was henceforth to belong to the masses, that it was to be a weapon in the class struggle. Arias of bourgeois depravity could not convincingly be sung by a Maria Callas.

But could they convincingly be sung by anyone else but Lotte Lenya?

As yet the question remains unanswered. A lot has been written about the sandpaper. But that is not the point. The point is that it abrades the metal coating of indifference from human souls. Lenya's is a voice and a style of musical recital that constitutes a new art form. And that art form is uniquely suited for Brecht's message.

Lenya's style was soon adapted by Marlene Dietrich, Greta Keller, Zarah Leanders and others who made the trenchant merely sexy and took it to the nightclubs and cabarets. Lenya always kept it on the legitimate stage.

The "Mahagonny" Singspiel Brecht, Weill and Lenya presented in Baden-Baden was a small success. It encouraged Brecht and Weill to start work on the full opera of their mythical city of greed. But a commission interfered. Ernst-Josef Aufricht, a young producer, had just bought Berlin's Theater an Schiffbauerdamm. He needed a sensation to open with.

He got it. Commissioned by Aufricht, Brecht and Weill hurriedly wrote "The Threepenny Opera" to meet the deadline. The dress rehearsal on Aug. 30, 1928, was more than commonly chaotic. Weill just about cracked when he discovered that Lotte Lenya's name was accidently omitted from the program. At the time, of course, she was virtually unknown.

The next day she was famous.

Together with Weill, Brecht, Dietrich, Max Reinhardt, Paul Klee, Mies van der Rohe and all the others, she had become part of Weimar Culture. The Weimar Republic, however, lasted less than five more years. The Weills fled, to France, the day Hitler stamped it out.

Weimar culture was, in a way, symbolically transplanted to these shores when Max Reinhardt, in 1935, staged his super-colossal biblical drama, Franz Werfel's "The Eternal Road," in New York. Reinhardt brought Weill to America to write the score. Lenya had a small part in it.

America enthusiastically welcomed the immigrant talent. But the run and the fame of "The Eternal Road" was less than eternal.

While the others soon became American celebrities, Lenya was famous no longer. For 10 years of so, she dropped out of sight. "At that time, hardly anyone here had heard of 'Pirate Jenny' and 'The Threepenny Opera,'" she said. "There wasn't really anything for me to do -- except to help my husband the best way I could. I stayed home and kept house for him so he could work. And, oh how he worked."

Kurt Weill worked hardest at becoming an American, not just an American citizen, but an American composer .

Brecht probably would have liked to continue the partnership (they tried doing an opera about "The Good Soldier Svejk"), but Weill, as Lenya related it, "was damned if he'd go on setting Karl Marx to music." There was nothing he wanted to protest in America.

On the contrary, he like so many other German artists, had all along been in love with the new world, with jazz, cowboys, silos and the moon of Alabama. In Berlin, Brecht and Weill had written songs in pidgin English. In New York, Weill wanted to write American songs, in the American manner, for an American audience, in American English.

"The problem was to find new writers, new librettists," Lenya said. "In Berlin we did not have to look for artists. They were somehow always there.If you did not find the person you wanted at Cafe Schlichter, the most popular hangout for theater people, you'd find him at the 'Kuenstler Eck' in the Genthiner Strasse."

In New York, as a newcomer, it was tough. Yet Weill probably found -- and was found by -- more, and more important American playwrights, than any other American theater composer. He worked with Alan Jay Lerner, Maxwell Anderson, Ogden Nash, Langston Hughes and Ira Gershwin, among others. Beginning with "Johnny Johnson," in 1936, he gave us one musical hit after another: "Knickerbocker Holiday," "Lady in the Dark," "One Touch of Venus," "Street Scene," "Lost in the Stars."

Suddenly Weill was dead of a heart attack.

That was in 1950. He was only 50 years old. "I still can't talk about it," said Lenya.

She kept on living quietly in their house in the country, some 30 miles from Broadway. Eventually she married again -- George Davis, a magazine editor.

But wait. That's not the end of the story. Lotte Lenya lit yet another cigarette and thought awhile just how the flame was rekindled.

"It was in 1953," she said, "when Leonard Bernstein suggested we arrange a Weill concert at Brandeis University. It was an enormous success. Everybody kept humming 'Threepenny Opera' for days and days.

"Shortly afterwards, a German record company asked me to record Weill's 'Theater Songs.' The time was just ripe for that kind of revival. Germany rediscovered us. The new fame spilled over to America.One producer after another called, asking to do 'Threepenny Opera.' But they all wanted to change it. They said it was too difficult or too this or too that. I kept saying, sorry, we produce it exactly as written or we don't produce it.

"And then one day these young people -- Carmen Capaldo and Stanley Chase -- asked if they could do the Marc Blitzstein translation, exactly as written, off-Broadway in the Theatre de Lys.

"I sang Pirate Jenny again and the show ran for just a few days short of seven years."

The flame, one might say, became a wildfire.

Louis Armstrong made "Mack the Knife" a global hit. At one time, "Threepenny Opera" was simultaneously performed on both sides of the Berlin Wall. On our side, as of old, the good burghers presumably enjoyed being twitted by those heroic proletarians. On the other side, the would-be proletarians presumably enjoyed being represented as witty and eloquent.

In reality, of course, this immoral morality play, having lost its social significance, had become all the more significance as a work of art

Lenya more or less stage-managed the revivals. She helped produce and sang in a German recording of an "Ur-Dreigroschenoper," (Three Pennyopera) as it were. It includes songs that had been cut (in part as too daring) from the original production. While she worked on it in Berlin, George Davis, her second husband, died of a coronary thrombosis.

The shows kept going on. Some years ago, Lenya helped Ian Strasfogel and what was then known as the Washington Opera Society with a glittering production of Weill's and Brecht's "The Decline and Fall of the City of Mahagonny." Last year, she did the same for the New York's Metropolitan Opera.

Earlier this year, "Silverlake," one of Weill's first operas, had its American premiere in New York.

"Weill's classical things are coming back," Lenya notes with satisfaction. At the Washington Musem of American Art musicale, a very early Weill cello sonata was performed.

Would she like to go on stage again, she was asked. She did not hesitate one moment. "Of course I would." She said it with the same, warm bubbling matter-of-factness with which she answered all other questions.

"But movies would be even better. I would like to play in a movie again. It's somehow easier. I'd enjoy that very much."