Had it been trimmed from two discs to one, Donna Summer's Bad Girls could have been an end-of-the-decade, Seventies masterpiece, seizing and encapsulating this moment in pop history. Even with side three's ultraschlock ballads and side two's erratic rockdisco cuts, it still ranks as the only great disco album other than Saturday Night Fever. Indeed, Bad Girls picks up where the John Travolta movie's sentimentalized, everybody's-a-star pop philosophy left off. If everyone's a star, it follows that everyone's also a commercial product, right? If that's true, where do you draw the line between being a self-created object of erotic fantasy and a hooker?

The notion that the world's a brothel is hardly new to pop music. Bette Midler gets a lot of laughs from imitating a bawd, and, on Don Juan's Reckless Daughter, Joni Mitchell paralleled imperialism to prostitution. Donna Summer, however, doesn't exploit the sexual jungle for humor or "art," but for sheer raunchy exuberance. In a move as naive as it is audacious, the singer herself writhes on the auction block, playing as hot-to-trot a streetwalker as ever sashayed down Broadway. Though the concept isn't developed as consistently as it might have been—the hooker-slanted tunes are interspersed with conventional love songs — Bad Girls amounts to a virtual paean to commercial sex.

Summer's vocals are wonderfully right for the part, and she stretches her chameleonlike voice to new limits, adding the role of rock & roll singer to her already established sex-kitten and Las Vegas-schlockmistress poses. The breakthrough cut is "Hot Stuff," a sizzling plea for action, whose slightly retarded, toughened disco rhythm and stinging Jeff Baxter guitar solo suggest Foreigner-style rock, without rutting the energy in metallic sludge. Summer's characteristic coyness is replaced by a hard-boiled, street-cookie directness that makes Linda Ronstadt seem positively demure.

The energy and fun are magnificently sustained on sides one and four. "Bad Girls," with its nifty "beep-beep, toot-toot" chant/hook, cheerfully evokes the trashflash vitality of tawdry disco dolls cruising down the main drag on Saturday night. The streamlined pop swing of "Love Will Always Find You" and "Walk Away" smoothly integrates Maria Muldaur-like nostalgia into the pop-disco mainstream. Summer's never sounded this playful and sophisticated. "Dim All the Lights" flaunts a saucy, Latin-flavored proposition, while "Our Love" is the apotheosis of every Sixties girl-group tear-jerker, updated for disco. Wailing in front of discofied African drums, Donna Summer sounds like the Shirelles reincarnated as a mightily love-struck Bionic Woman. In "Lucky," the pulpy saga of a one-nighter, the singer meows in front of a plunging, suction-cup synthesizer whose salacious slavering practically defines lasciviousness.

The closest thing to a social comment on Bad Girls comes in "Sunset People," a sweeping, high-rise view of Hollywood. Against an icy refrain of "doin' it right — night after night," the song telescopes the nightmarish glamour world of the Sunset Strip—with its teenage prostitutes, billboards, foreign cars and star worship — into an evocation of pleasureseeking as cold as it is tantalizing. If there's a moral here, it's in the music's ominous suggestion of the boredom beyond glitter and in the lyrics' telegraphed equation of the disco ethos with Hollywood and hooking. "Sunset People" just might be the disco culture's "A Day in the Life."

In one of the photos on the LP's inner sleeve, Donna Summer's co-producer, Giorgio Moroder, poses as her pimp. That's as good a metaphor as any for their musical interaction. Moroder's technique simultaneously mocks and exalts the star, who becomes both a goddess and a sideshow attraction in a futuristic technosex amusement park. Though this record's production contains nothing as startlingly novel as the sequenced bass synthesizer of "I Feel Love," the best tracks strike a perfect blend of German Eurodisco and American rock and soul that ultimately transcends the disco environment. Bad Girls' aural style is a lot sparer than the mechanized swirls of "Mac-Arthur Park Suite" and Once upon a Time....The new album's sound effects — e.g., the backward tape loops that sound like speeding cars in "Sunset People"— seem integral to the material.

Bad Girls' only serious lapse is side three, which consists of four sappy ballads, all of them cowritten by Summer. Working with lyrics that are embarrassingly mawkish, the singer overemotes in a painfully flat, syrupy sob, while the Eurodisco-pop synthesis that works so beautifully elsewhere collapses completely in these lengthy, unstructured weepers.

Such gross miscalculation shouldn't really come as a surprise, however, since Summer is truly a left-field phenomenon. Like Marilyn Monroe, whom she consciously emulates, Donna Summer is a gigantic but primitive talent whose reckless abandon and astonishing innocence (dumbness?) are two sides of the same coin. How else could she give herself so totally to the role of sex symbol? Summer is the Fifties' child-woman sexual ideal "liberated" into a Seventies, multiorgasmic Cosmopolitan clone — an inflatable sex machine as insatiable as she is helpless. But like Monroe, Summer also remains a true naif. She's more a monstrous reflection than a cynical projection of our collective libido. I guess the souls of our archetypes don't change, only their manners.

Two records ago, on Once upon a Time..., Donna Summer turned Cinderella into a disco fable. On Bad Girls, Cinderella has grown up to be a whore, and Prince Charming a john. Nowadays there's a ball every night down at the discothèque, and Happily Ever After is just another low-priced "zipless fuck." (RS 295)

STEPHEN HOLDEN