On February 1 -- in a now world-famous moment -- during CBS's broadcast of MTV's Super Bowl halftime show, Justin Timberlake exposed Janet Jackson's breast. The breast was covered only by a sun-shaped piece of jewelry attached to her nipple piercing.

The outrage that followed was extraordinary. The network subsequently received numerous viewer calls -- with many parents complaining that while they were watching the Super Bowl with their children, the family tradition had been interrupted by unexpected nudity.

No one doubts that these complaints are warranted. Parents had every right to anticipate what the show would be like, and children saw something their parents had a reasonable expectation they would not see. And whatever one thinks of broadcast censorship - to which, as I explained in a prior column, I am strongly opposed -- thwarting these expectations was the wrong thing to do.

Nevertheless, the complaints could have been fully addressed simply by increasing the time delays that allow review -- and censorship -- of live broadcasts. Indeed, that's exactly what happened on the Grammy Awards, aired the following Sunday, February 8. And of course, with the "enhanced" time delay, nothing remotely like the Jackson breast exposure occurred.

So is it time to forgive, forget -- and simply mandate the use of enhanced time delays? Not according to the FCC or Congress. Both have used the Jackson incident as a wedge to try to enact further speech restrictions -- restrictions that have nothing to do with the original incident. And in doing so, both have seriously threatened Americans' First Amendment rights.

The chronology of the Jackson scandal clearly illustrates a major concern of First Amendment advocates: The "chilling effect." This concern arises from the fact that when someone is punished -- or left in limbo, awaiting possible punishment -- because of the way they exercised their First Amendment rights, the predictable result is that others feel less free to speak.

In First Amendment parlance, their speech is "chilled." And from a constitutional perspective, that is a big problem -- one that worries liberal and conservative Justices alike. (For an example of conservatives' concern about chilling, check out the dissent from the Court's 2001 decision in Bartnicki v. Vopper.)

In the Jackson/Timberlake case, the chill has expanded to Arctic proportions. The frost set in instantly on February 2, after both Jackson and Timberlake issued statements apologizing, and saying that a mistake was made -- a mistake Timberlake termed a "wardrobe malfunction." According to both performers, Timberlake was supposed to reveal only Jackson's red lace bra -- not her breast. Moreover, both said that neither CBS nor MTV was apprised of the planned red-lace-bra reveal beforehand, for it was not included in rehearsals.

It's unlikely that Jackson and Timberlake are lying, given that numerous witnesses were present at the rehearsals. So given that the evidence suggests the nudity was unintentional, and given that skimpy outfits such as the one Jackson planned to reveal are now quite common (remember Madonna's cone-shaped bra?), one might have thought that the performers' apologies and explanations would have ended the matter.

But in fact, the fallout from the incident has been harsh. The day after the Super Bowl, FCC Commissioner Michael Powell ordered an investigation -- and he stressed that it would reach not only the "nipplegate" incident, but also the entire halftime show, which he described as nothing more than "onstage copulation." (See Michael Dorf's column for an explanation of the FCC regulations and First Amendment cases that will set the parameters for Powell's investigation.)

Powell also threatened fines for all of the relevant stations -- even affiliates and local stations that no one has claimed knew anything about the stunt. He also made clear that his standard of decency was, in essence, "I know it when I see it," commenting, "I don't think you need to be a lawyer to understand the basic concepts of common decency here."

The networks listened, and so the "chilling effect" began. On February 5, NBC aired an "E.R." episode only after editing out a scene that would have shown a glimpse of an elderly patient's breast -- even as "E.R." Executive Producer John Wells complained of the "chilling effect" on "dramatic integrity."

At around the same time, MTV decided to make some changes to its video rotation -- relegating certain videos, such as Britney Spears's video for "Toxic," to the 10 p.m. to 6 p.m. rotation that many joke is suited only to insomniacs.

Then, on February 11, Congress vowed to focus on "indecent" shows offered via satellite, and on cable -- where speech has traditionally been freer than on network television.

In sum, the chilling effect here seems to have been expanding. Not only has the investigation into the Jackson/Timberlake incident grown to encompass the whole Super Bowl half-time show, but cable programming is under scrutiny; networks are making pre-emptive changes even to programming, like "E.R." that is designed to be watched primarily by adults; and MTV is changing its video rotation, so that controversial videos are played only when children are likely to actually be asleep.

We should worry greatly about chilling effects that inhibit free speech -- especially an ever-expanding chilling effect such as the one that is occurring here. When speech is silenced, not only the speakers, but the potential listeners -- and society as a whole -- lose out. Fewer messages are sent; the diversity of views is lessened; and our communications media -- in this case, television -- are impoverished.

Even if readers find the Jackson stunt itself to be more shock tactic than speech, it's important to remember that shock itself can send a strong message. For example, in 1993, the New York Times Magazine featured a photo of the artist Matuschka's post-mastectomy breast scar on its cover. Shocking? Yes, but also an unforgettable reminder of the omnipresence of breast cancer.

Moreover, even those who question the value of Jackson's apparently inadvertent message, might still worry about the chilling effect on others when the government comes down so hard on Jackson. Does anyone really question the existence, or value, of the message in "E.R."'s attempt to depict an elderly patient's breast-related medical treatment? Certainly, we should be concerned if a medical drama cannot depict serious medical conditions as they exist in real life.

Yet in the wake of the Jackson matter, not only does FCC Commissioner Powell seem unconcerned about a chilling effect, he seems actually to be willing to exacerbate it -- in several ways.

First, Powell has suggested fines for violations may now be increased greatly. But why? The outcry over the Jackson event was doubtless, in itself, sufficient warning to anyone who might have contemplated risking another violation. The current fines -- or even the threat of them -- are obviously more than enough.

Second, Powell has made clear that he has no problem with imposing strict liability -- that is, liability regardless of fault -- on broadcasters. Even entirely blameless local stations and affiliates will be swept within his net, he has insisted. But that's unfair: Only culpable parties -- if any -- should be punished.

Third, Powell has indicated that he will apply a vague and capricious standard as to what is indecency -- a standard that you "don't have to be a lawyer" to understand. But without legal wording, and legal limits on what can be considered indecent -- that is, without strict legal lines drawn in the sand -- the chilling effect will only be amplified. Any speech that the speaker fears might run afoul of viewers' sensibilities will predictably be chilled.

Fourth, Powell unjustifiably expanded his investigation to the entire half-time show. Doubtless, without the nipple-baring incident, the half-time show itself would never have been investigated. The nipple-baring incident thus should not serve as a pretext to investigate the entire half-time show.

Finally, and perhaps most disturbingly, Powell tried to label Jackson a liar -- or at least, a probable liar -- even before any investigation had begun. As CNN reported, Powell commented, "Clearly somebody had knowledge of it. Clearly it was something that was planned by someone . . . . [Jackson] probably got what she was looking for." (Emphasis added). Particularly in a case involving free speech, investigators should not go in biased against the subject of the investigation.

Powell has a right to investigate if he so chooses. But he should properly limit his investigation to the nipple-baring incident alone, and stop targeting those who weren't involved. He should also clarify the standards under which he will conduct the investigation, and begin with the presumption that Jackson and Timberlake are innocent, as they have claimed.

Otherwise, Commissioner Powell risks causing serious First Amendment harm.