THEATER : A Devilishly Tough Thing to Do : Commentary: The new ‘Faust’ would seem to be a boost for the stage musical. But aficionados know the form is demanding. So are they.

A startling thing happened last weekend. I got in my car, turned on the radio and heard a pop star, decades younger than Sinatra, singing a new song from a new musical.

This does happen occasionally--and we don’t have to go all the way back to the days of Jerome Kern to find examples: Barbra Streisand crooning Stephen Sondheim’s “Send in the Clowns” (from “A Little Night Music”) or Andrew Lloyd Webber and Trevor Nunn’s “Memory” (“Cats”) crossed over so far we got sick of hearing them.

But the song I heard a week ago had infinitely more buzz . This was Bonnie Raitt singing a bluesy number called “Life Has Been Good to Me” from the wickedly funny new musical “Randy Newman’s Faust.” Because it bore the distinctive stamp of Randy Newman, the song didn’t carry the cultural stigma of coming from the musical theater.

For me, the incident was a stirring reminder that the world was a very different place when its “pop” songs were supplied by Rodgers and Hammerstein, Irving Berlin and Frank Loesser. In 1945, when the composer Arthur Schwartz wrote a tribute to Jerome Kern in Look magazine, he began by noting: “Switch on your radio any time this evening and it’s 10 to 1 that within an hour you will hear the limpid, lovely strains of a Jerome Kern song.” And the same would have been true at a nightclub, or at the movies, or if you just listened to what was in your head. In those days, theater music was America’s music.

By 1960, when Charles Strouse and Lee Adams opened “Bye Bye Birdie,” popular music had become rock music, and its agenda had nothing to do with the legitimate stage. “Bye Bye Birdie” was a great musical, a popular musical, but it was not really a part of the country’s popular music. The show may have satirized Elvis, but it wasn’t Elvis. And Elvis and the people who wrote the music he recorded didn’t have the slightest interest in the musical theater. Nor did most of Elvis’ audience.

Since then, many have tried to push the musical back into its former prominence by adopting, or imitating, the sounds of the day. That strategy worked sporadically, and one can count Galt MacDermot, Gerome Ragni and James Rado’s “Hair” (1968) and Andrew Lloyd Webber and Trevor Nunn’s “Jesus Christ Superstar” (1971) as early successes in the battle. Lloyd Webber’s achievements set off a wave of disciples. Just two months ago, the Orange County Performing Arts Center hosted “Jekyll & Hyde,” a new Broadway-bound, faux-Lloyd Webber vehicle whose courting of a pop audience was so shameless that its songs made better sense when extracted as Olympic skating music than they did in the text itself.

But by far the most successful of the post-Lloyd Webber writers are Claude-Michel Schonberg and Alain Boublil, the composer and lyricist of “Les Miserables” and “Miss Saigon.” These men (and producer Cameron Mackintosh) created wildly successful, lushly dramatic musicals that brought a huge international audience into the musical theater. The number of tickets sold bestowed a kind of significance on these shows, but they didn’t do much for the form critically or culturally.

For years now, critics and other devotees have suggested that the musical might be saved from its perceived slide into irrelevance if authentic pop (or rock) practitioners came into the fold. This idea became even more compelling after the 24-year-old rock opera “Tommy” was adapted into a hit Broadway musical (“The Who’s Tommy”) in 1993. Of course, “Tommy’s” success owed much to the theatrical savvy of Des McAnuff, who was able to provide a theatrical catharsis at the end of a rock opera that, arguably, did not have one before.

So, aside from Pete Townshend, which pop composers have been named as potential saviors? The logical candidates are the ones who have excelled at painting story and character in song. Among those suggested over the years: Billy Joel, Paul Simon, Jackson Browne, Bruce Springsteen, Randy Newman, Prince. Of all of them, Newman, with his divine sense of satire, was the most exciting to contemplate.

Now Simon is at work with poet Derek Walcott on “The Capeman,” about a real-life York murder, a musical that we might see in Chicago next year. And Newman has opened “Faust” at the La Jolla Playhouse, the same theater that launched “The Who’s Tommy.”

Newman has delivered a show that is as impossible to hate as it is to love. If “Faust” tells us anything, it is that the marriage of pop writers to the theater is not quite as logical and simple a solution as it seemed. “Faust” illustrates the profound difference between telling a story in song and using songs to tell a story. These skills may be similar, at times overlapping, but they are not interchangeable.

The first definition of a theater song is that it must fit into a book. A book is not merely the spoken dialogue but also encompasses the structure of the story, as well as the style of the show. Newman, who could benefit from the help of a seasoned book writer, seems oblivious to Oscar Hammerstein’s point in the 1949 essay “Notes on Lyrics”: “The song,” he wrote, “is the servant of the play.”

Newman has written a terrific revue, but a terrible show. Almost immediately, “Faust’s” book betrays the fact that the composer does not know how to use song to build a dramatic arc. Songs are introduced for no dramatic reason, and they fade into the background without advancing the story or character. Newman’s book is witty, naughty and original, but it is also careless.

Characters are not developed commensurate to their songs or even to each other in a way that makes any kind of sense. We know why the idiotic, heavy-metal-loving Faust is drawn to the virginal and square Margaret: Cupid shot him with an arrow. But why is she drawn to him? This relationship is treated by the book as farce and by the songs as real. When this woefully mismatched pair turn to each other and sing “Feels Like Home,” a gorgeous, earnest love song, a theater-goer who has been enjoying the show’s devilish wit may experience serious cognitive dissonance.

It should be said that theater songs appear infrequently on the radio these days not only because they jumped off the pop-rock boat but because the best of them are often so deeply embedded in a story that they become incomprehensible when divorced from their purpose.

Imagine turning on the radio and hearing an operatic baritone singing dissonantly: “And what if none of their souls were saved? / They went to their maker impeccably shaved / by Sweeney / by Sweeney Todd.” It would be hard to get the joke. That lyric is, of course, from “Sweeney Todd” by Stephen Sondheim, one of the greatest musicals in the entire canon (I’d put it in the top three). Not surprisingly, none of its songs found real commercial success. “Feels Like Home,” on the other hand, unfolds its beauty best on the all-star recording of “Faust,” not on stage.

In the end, “Faust” seems to be trying to pass itself off as a lighthearted parody of musical theater, but it doesn’t achieve parody. Newman is obviously capable of satire of the most delicious nature (two words: “Political Science”). But in “Faust” he is parodying a form he has only a cursory understanding of, and, apparently, little respect for.

I, for one, greet the success and failure of “Faust” with profound ambivalence. In the best of circumstances, it should encourage other composers to approach the musical theater with joy, idiosyncrasy, but also with the respect it deserves. Done right, musical theater is a demanding art and very powerful form of theater. Those of us who are its fans actually don’t care if the rest of our culture deems what we love irrelevant--just as long as it’s the real thing.