Many continuing threats to civil liberties in America are completely unrelated to terrorism or to national security. Furthermore, many civil libertarians are silent about these abuses, because they are motivated by "progressive" goals -- such as ostensibly protecting women from abuse.

Consider the widening reach and the unintended consequences of rape shield laws. These statutes, hailed as a way to keep victims from being smeared as sluts in court, have sometimes kept juries from hearing evidence highly relevant to the guilt or innocence of the accused.

On November 1, a court in Manhattan dismissed all charges against Oliver Jovanovic, a student at Columbia University. Jovanovic was at the center of a notorious "cybersex" case involving an Internet acquaintance, a real-life date, and accusations of kidnapping, sexual assault, and sexual torture.

In 1998, Jovanovic was convicted of attacking Barnard College student Jamie Rzucek (whose name has been disclosed by some media outlets after the case was dismissed) and was sentenced to a minimum of 15 years in prison. Rzucek claimed that Jovanovic held her captive in his apartment for 20 hours and subjected her to torture and sexual abuse. The defense argued that there was no torture -- Rzucek's claim that Jovanovic forcibly sodomized her was disputed by medical evidence, and the jury returned a not-guilty verdict on the counts pertaining to this act -- and that the bondage was consensual.

This argument was crippled by Judge William Wetzel's decision to exclude portions of the e-mail correspondence between Jovanovic and Rzucek in which she discussed her adventures in sadomasochism, including her sadomasochistic relationship with another man. The messages, the judge held, were inadmissible under New York State's rape shield law because they had to do with the accuser's sexual conduct.

In late 1999, the Appellate Division of the New York State Supreme Court, by a 3-to-1 vote, set aside the conviction on the grounds that Judge Wetzel had applied the rape shield law improperly and left the jury with a "distorted view of the evidence." The case was sent down for retrial, but Rzucek proved reluctant to testify a second time, and prosecutors eventually sought a dismissal "in the interests of justice." Jovanovic's vindication came at a high price: as much as $500,000 in legal fees, not to mention 20 months spent in state penitentiaries.

Rape shield laws, which mostly date from the 1970s and are virtually universal today, enjoy broad public support. In surveys, about three-quarters of Americans agree that a woman's past sexual life should not be an issue in a rape case. Indeed, it seems obvious that to quiz a woman who says she was raped about whether she has had two, 10, or 20 sexual partners is not only cruel and degrading but irrelevant to the question of whether she consented to sex with the man in the dock. But in quite a few cases, rape shield laws have been applied to evidence that has a direct bearing on the credibility of the accuser (and, sometimes, only the most tenuous connection to her sexual past).

Prior to the Jovanovic trial, the most notorious case to raise these issues was that of sportscaster Marv Albert, who was accused by his longtime friend and sex partner Vanessa Perhach of oral sodomy and assault. At the 1997 trial, notable for tawdry details of transvestitism and kinky sex, Albert's attorneys wanted to bring up Perhach's alleged conduct with other men, particularly men who left her -- as Albert, who was getting married, was about to do. She had reportedly harassed and threatened a former boyfriend's family, and may have made false accusations of crimes as a form of revenge. A former lover was also willing to testify that biting, on which the assault charge against Albert was based, was a part of her sexual repertoire.

All this testimony was barred by Circuit Court Judge Benjamin Kendrick. (Meanwhile, a woman who came forward with a claim that Albert had sexually assaulted her several years earlier was allowed to take the stand.) With the defense's hands tied, Albert pleaded guilty to misdemeanor assault. The outcome struck many observers -- even those, such as Geraldo Rivera, who are generally sympathetic to victims' rights -- as shockingly unfair.

And then there are the more obscure cases:

-- In Wisconsin in 1993, 18-year-old Charles Steadman was convicted of raping his 22-year-old foster sister Jessica in a he said/she said case in which physical evidence of force was absent and the defendant claimed that the sex was consensual. What the jury didn't know was that when Jessica filed the complaint, she herself was facing criminal charges of having sex with minors. (She eventually received probation with mandatory psychiatric treatment.) Clearly, this gave her a reason to lie -- particularly since she had had sexual relations with Steadman when he was underage. She might have thought that being a victim would improve her legal situation as a defendant, or she might have worried that if her encounter with Steadman became known, she would get in more trouble with the law. None of these possible motives could be introduced at Steadman's trial, since Jessica's legal problems were related to her past sexual activities and hence inadmissible.

-- In Oregon in 1989, James Anderson was convicted of raping "Donna R." while both were patients at a substance-abuse clinic. Anderson insisted that the sex was consensual and that Donna made up the charges in order to sue the clinic, which threw her out the morning after the alleged rape because she wouldn't sign up for long-term treatment. After initially claiming that she had tried to tell clinic staffers about the attack but was rebuffed, Donna reversed herself under cross-examination and said that she had not spoken about it to any of them because she was too embarrassed. In his summation, the prosecutor sneered that the defense expected a rape victim to "just walk up to one of the staff" and discuss "those most intimate details."

The jurors were never told that the day before, she had discussed equally "intimate details" -- an alleged earlier rape and childhood sexual abuse -- with one of the counselors. All records of this conversation were excluded from the trial under the rape shield law as pertaining to the accuser's sexual history; so was the fact that Donna had given several inconsistent accounts of her prior sexual victimization. Whether or not Donna was raped, the case seemed to leave ample room for reasonable doubt -- particularly if one knew that Donna was not a reliable witness.

When rape shield laws were first enacted as part of the rape law reforms initiated by the feminist movement, they were a response to truly abusive practices. Just 30 years ago, jurors in rape cases were often formally instructed to consider evidence of "unchaste character" (such as going to bars alone, extramarital liaisons, and use of birth control) as detracting from the complainant's credibility or indicating that she was more likely to have consented to sex.

But in recent years, even some feminist legal theorists, such as Vivian Berger, have expressed concern that the pendulum may have swung too far. Granted, the accuser's past sexual conduct is not automatically excluded -- just as, before shield laws, it wasn't automatically allowed. Her prior relations with the accused are generally admissible; so is evidence that the pregnancy or disease alleged to have resulted from the rape may have been caused by sex with someone else. In some states, other evidence may be admitted at the judge's discretion.

Most of the time, however, the burden is on the defendant to show that the value of this evidence to his case outweighs its "prejudicial effect" on the complainant. In several states (including Alabama, Iowa, and Washington), courts have held that excluding evidence of an earlier false or dubious rape complaint by the accuser does not deny the accused a fair trial -- even, perhaps, if the evidence is relevant to the question of his innocence.

In some cases, such as People v. Jovanovic, appellate courts have curbed the worst abuses of rape shield laws. But this is an issue that is overdue for a new look by legislatures, even if reforms are likely to engender a furious reaction from feminist groups.