pity Katie Roiphe, the young writer who brashly contradicted feminist orthodoxy with "The Morning After: Sex, Fear and Feminism," a challenge to anti-date-rape women's groups on today's university campuses. She has a lot to prove.

When, in the early '90s, "post-feminists" like Roiphe resisted the priggish dogmas of '80s feminism, they presented themselves as dashing, sexy "bad girls" who dared to defy sob sister victimology, protectionism and male bashing. The fact that Roiphe is literally the daughter of Old Guard feminism -- her mother, Anne, is the author of the feminist classic, "Up the Sandbox" -- gave her publishing debut a piquant Oedipal twist. "The Morning After" nabbed the 25-year-old Roiphe a cover story in the New York Times Magazine and ink in many national publications. But sassing Mommy is the easy part, especially when you get plenty of attention for doing it. Now is the time for thinkers like Roiphe to deliver the goods: some intimation of a next generation of feminism that will inspire women to new heights.

Roiphe has just published "Last Night in Paradise: Sex and Morals at the Century's End," a work mostly concerned with how the AIDS crisis has affected Americans' sex lives. It's a noticeably edgy and evasive second book, as if Roiphe hopes that by constantly shifting her position she'll avoid some of the body blows she took as a result of her first. Katha Pollitt briskly decimated "The Morning After" in The New Yorker, dispatching Roiphe's critique of rape frequency statistics like a lioness gruffly swatting down a cub whose friskiness has grown tiresome. Of course, Roiphe expected ideological critiques -- she'd already been the target of many outraged sophomore fanatics. But Pollitt hardly needed to bother with that; she simply analyzed Roiphe's "reporting," in one example after another, and showed it to be lazy, shallow and inaccurate, based on rumor, exaggeration and, at times, just plain stupidity. "Don't they teach students ... anything about research anymore?" Pollitt growled.

The problem with commentators like Roiphe is that the same half-cocked, extravagant assertions that make them such good copy also make them easy to dismiss. The overwrought, fear-mongering mentality of the campus anti-rape movement in the early '90s (particularly freshman "orientations" pitched to the upper registers of gender-war hysteria) deserved to be debunked. But Roiphe's rank carelessness in questioning rape statistics (a relatively minor issue) enabled her opponents to disregard her solid complaints that rape "education" programs only fostered female helplessness and dependency on institutions.

Although Roiphe insisted that "The Morning After" was "not a political polemic," it was just that. With "Last Night in Paradise," by contrast, it's impossible to glean any clear indictment or recommendation from her tortured musings. Roiphe sees American culture as having seized upon AIDS as an excuse to resume a puritanical stance on sexuality. All too quickly, pious headlines calling the disease the "price" of the sexual revolution appeared. The public's eagerness to embrace homilies and codes about safer sex, abstinence and monogamy betrays, she argues, a panicky discomfort with the rampant hedonism of the '60s and '70s. "All the indulgent voices left some fundamental need for control unsatisfied."

This crackdown bothers Roiphe, who mourns "an ideal of recklessness and abandon that's in the process of being lost." But then again, she also welcomes it.

Roiphe describes having felt a deep, intermittent "revulsion" about the casual sexual relationships of her college years, the parade of young men who traipsed through the flat she shared with three female roommates. "I felt almost sick with the accumulated anonymity of it," she writes. "It was then that I first felt a hint of our absolute readiness for limits, for someone to say, for whatever reason, this is not a healthy way to live." Later, she watched a TV commercial warning, "If you've had sex with two people, and each of those two people have had sex with two people ..." and showing a lone waltzing couple gradually joined by more and more people until finally they're dancing in a crowded room. In this light, "my own fairly average romantic history seems impossibly sordid."

That said, Roiphe returns to lamenting the new mania for "caution." Readers of "The Morning After" will recognize this yearning for chaos, danger and mystery, things Roiphe finds essential to her notion of passion. She admiringly and at length describes the autobiographical French film "Savage Nights," written and directed by Cyril Collard, an HIV-positive bisexual who also stars. This slab of Gallic dreck (I've seen it, unfortunately) concerns a group of young, leather-clad urbanites who spend most of the movie shrieking about l'amour and chewing up the scenery. The hero, a preening Lothario, beds a young woman without informing her beforehand that he's infected. When the woman discovers this, she melodramatically casts away their condoms, crying "I want to share everything with you, even your disease."

"This is love," Roiphe gushes. "True love is not concerned with self-protection" or "the selfishness and prudence written into our new sexual ethic." That Roiphe sees pointless self-obliteration as the pinnacle of love reveals her startling similarity to the passive girls she decries in "The Morning After." In fact, in a recent essay in Esquire, Roiphe confesses further to "forbidden" fantasies about being "taken care of" by a man of means. In traditional sex roles, she writes, "you can take a rest from yourself ... equality is not always, in all contexts and situations, comfortable or even desirable."

Actually, it's being in charge of your own life that's not always comfortable, and many people go to great lengths to avoid it, Roiphe apparently among them. Whether fretting about "permissiveness" or balking at excessive "caution," she seems to see her sexuality as public property constructed of magazine articles and surveys, a weather vane that obediently turns with whatever trend is currently breezing through the culture. She's one of those feminist writers who's forever kvetching about what women are "supposed to be," as if we all have to be the same and feminism is just a matter of settling on the right boilerplate.

A conversation with Christine, a self-described "secondary virgin" (someone who has abandoned premarital sex and intends to remain celibate until marriage), lashes Roiphe into a frenzy. At first, she envies the other woman's "glow" and serenity, but if Roiphe acknowledges the legitimacy of Christine's choice -- according to her own crazy logic -- that would mean she'd have to follow her example. Instead, Roiphe decides that Christine's "calm" is "delusion" and "I find myself infuriated. I suddenly want to convert her more desperately than she wants to convert me, although there are definitely times when I wish that, like Christine, I had a giant book that would tell me how to live my life." Whew! No wonder Roiphe's confused. The possibility that Christine's is a purely personal decision that works for her and has no bearing on Roiphe's own sex life never seems to occur to her.

For all Roiphe's touting of willful passion and adventure, "Last Night in Paradise" is really just a book about norms; it's remarkable how much she dwells on what other people think. When promiscuity was fashionable (in her early college years), Roiphe dreaded being thought a virgin. Now she frets that "if you smoke a cigarette or order a glass of wine at lunch, people will look at you as if you are somehow polluting ... the moral environment of the nation." There's nothing here, really, about sexual pleasure or freedom, nothing about the demanding but ultimately liberating discovery of private truths. Roiphe just ping-pongs between wishing it were considered "OK" to collect sexual experiences and longing for someone else to impose structure and morals on her emotional life. Whether she obeys or rebels, Roiphe doesn't know who she is.

With "Last Night in Paradise," Roiphe still shows herself to be a bad girl, but the title proves entirely unironic. And the operative word is "girl."