photo courtesy of CITY LIGHTS PICTURES John Waters' new comedy "A Dirty Shame," starring Tracy Ullman, Chris Isaak, Selma Blair and her rack, opens tomorrow.

When I first read about John Waters' new exercise in filth, "A Dirty Shame," I was ready for something utterly reprehensible.

Waters' cult classic "Pink Flamingos" defecated on the line between art and filth, splattering everything from fecal consumption to oral sex (decades before "Brown Bunny") all over a retrospectively sterile movie-going public. Its joyful, campy desecration of any bourgeois value you care to name brilliantly satirized both suburban America and the counterculture, while opening up prudish American cinema to the explicitly stated idea that the unclean and impure can bring freedom.

Now, 32 years after "Pink Flamingos" and following in the wake of a string of more tame releases ("Hairspray," "Serial Mom" and "Pecker," among others), Waters has earned an NC-17 rating from the MPAA with "A Dirty Shame."

It's a shame the film isn't dirtier.

The plot will be familiar to any Waters fan. The Stickles are a typical suburban family: comfortable, bourgeois and sexually repressed. Sylvia Stickles (Tracy Ullman) goes through her day in a repressed rage while husband Vaughn's (Chris Isaak) attempts to sleep with his own wife are in vain. Meanwhile daughter Caprice (Selma Blair) and her cartoonishly enhanced breasts stay locked up in the guesthouse, in the grip of permanent sexual fever.

But Caprice isn't the only one afflicted. It seems half of the town has come down with the same thing, their fetishes and desires running rampant. Sylvia is distressed by the whole affair until she is knocked unconscious in a traffic accident and revived by Ray-Ray (Johnny Knoxville), a kind of sexual Christ-figure.

Subsequently, a war between Ray-Ray's cult of hypersexual fetishists and the Neuters (led by Waters regular Mink Stole) plunges the town in maelstrom. As the cult searches for the ultimate sexual act, the most satisfying, undiscovered sexual maneuver ever performed, the Neuters try to bring an end to open sexuality and return the town to its muffled beginnings.

With the NC-17 rating and all, I was prepared for something truly gross, truly graphic and wild. Really, the rating seems to have been earned by a few scattered instances of full frontal male nudity. Compared to Waters' earlier work, "A Dirty Shame" is tame.

Even the much talked-about nursing home scene involving a game of hokey-pokey, Tracy Ullman's vagina and a water bottle is strangely unaffecting. The unshocking nature of the film seems partially derived from the broadly campy dialogue and exaggerated sexuality, which has become the John Waters trademark. Every character is a caricature and every sentence uttered ends in an exclamation point.

Ultimately we're not seeing anything new, or even particularly funny. "Pink Flamingos" was hilarious because the fact that someone would take the time and money to write and direct it was insane, beautiful and heroic.

Now Waters seems to think the same camp and sex jokes will register as shocking when it just isn't the case anymore. The search for the ultimate sexual act ends in a paradoxically unsatisfying revelation and even the film's obviously self-referential humor falls flat. The point seems to be that we live in a society so sensitive to sexuality, yet so jaded, that it is impossible for mere sex to do anything revolutionary even though it remains offensive.

All of this would be fine if the film's effectiveness didn't depend so heavily on being shocking. If its shock value were incidental to an otherwise compelling story, the case might be different.

Ultimately, we're left with a mildly amusing fairy tale about a sexual revolution 30 years past. Its laughs are few and far between and its only shock lies in its temerity.