Hopper leaves. Rossellini discovers MacLachlan in the closet and, to his astonishment, pulls a knife on him and forces him to submit to her seduction. He is appalled but fascinated; she wants him to be a "bad boy" and hit her.

These sequences have great power. They make "9 1/2 Weeks" look rather timid by comparison, because they do seem genuinely born from the darkest and most despairing side of human nature. If "Blue Velvet" had continued to develop its story in a straight line, if it had followed more deeply into the implications of the first shocking encounter between Rossellini and MacLachlan, it might have made some real emotional discoveries.

Instead, director David Lynch chose to interrupt the almost hypnotic pull of that relationship in order to pull back to his jokey, small-town satire. Is he afraid that movie audiences might not be ready for stark S & M unless they're assured it's all really a joke? I was absorbed and convinced by the relationship between Rossellini and MacLachlan, and annoyed because the director kept placing himself between me and the material. After five or 10 minutes in which the screen reality was overwhelming, I didn't need the director prancing on with a top hat and cane, whistling that it was all in fun.

Indeed, the movie is pulled so violently in opposite directions that it pulls itself apart. If the sexual scenes are real, then why do we need the sendup of the "Donna Reed Show"? What are we being told? That beneath the surface of Small Town, U.S.A., passions run dark and dangerous? Don't stop the presses.

The sexual material in "Blue Velvet" is so disturbing, and the performance by Rosellini is so convincing and courageous, that it demands a movie that deserves it. American movies have been using satire for years to take the edge off sex and violence. Occasionally, perhaps sex and violence should be treated with the seriousness they deserve. Given the power of the darker scenes in this movie, we're all the more frustrated that the director is unwilling to follow through to the consequences of his insights.