(WASHINGTON) -- The Supreme Court today limited some of the freedom-of-expression protections that permit nude dancing.

The justices, by a 6-3 vote, reinstated an Erie, Pa., public-indecency ordinance that requires women who work as barroom dancers to wear at least pasties and a G-string when performing.

Pennsylvania's highest court had struck down the law, ruling that it unlawfully infringed expressive freedom, as protected by the Constitution's First Amendment.

Today's decision is sure to have broad impact. Nude entertainment is featured in some 3,000 adult clubs nationwide, the justices had been told.

They said the Pennsylvania court was wrong.

Writing in the court's main opinion, Justice Sandra Day O'Connor said nude dancing is ``expressive conduct'' that merits some First Amendment protection.

However, she added, the nude-dancing ban furthers Erie's ``interest in combating the negative secondary effects associated with adult entertainment establishments,'' such as crime.

O'Connor said the ordinance was aimed at combating crime and other negative effects of having adult entertainment establishments, and not at the erotic message of nude dancing.

Even if the ban ``has some minimal effect on the erotic message by muting that portion of the expression that occurs when the last stitch is dropped,'' O'Connor said, the dancers are free to perform wearing pasties and G-strings. Any effect on overall expression is minimal, she said.

The main part of her opinion was joined by Chief Justice William H. Rehnquist and Justices Anthony M. Kennedy and Stephen G. Breyer.

Justices Antonin Scalia and Clarence Thomas, in a separate opinion by Scalia, voted to uphold the law on different grounds, citing ``the traditional power of government to foster good morals ... and the acceptability of the traditional judgment ... that nude public dancing itself is immoral.''

However, Scalia also contended the case was moot because the nightclub at issue, known as Kandyland, had been sold.

Justice David H. Souter wrote separately that he agreed with O'Connor's analysis, but that he believed the city had not shown its ordinance was designed to deal with ``real harms.'' He said the city should be given a chance to do so.

Justices John Paul Stevens and Ruth Bader Ginsburg dissented from the ruling, saying in an opinion by Stevens that the court had decided for the first time that secondary effects ``may justify the total suppression of protected speech.''

``Indeed, the plurality opinion concludes that admittedly trivial advancements of a state's interests may provide the basis for censorship,'' Stevens wrote.

The Erie dispute was not the Supreme Court's first tour of the far reaches of free-speech law. In 1991, a badly splintered court ruled that nude dancing is a form of expression within the First Amendment's ``outer perimeters'' and is entitled to some protection from government censorship.

But that 1991 ruling also allowed Indiana to ban all barroom-style nude dancing under a state law generally prohibiting public nudity.

The Pennsylvania Supreme Court, voting 4-3 in 1998, struck down Erie's ordinance after calling the splintered 1991 decision a ``hodgepodge of opinions'' that offered little guidance.

The 1994 ordinance had been challenged by Nick Panos, who used to own the Kandyland nude-dancing club. He since has sold the club to a new owner, Joseph Cunningham, who closed it down and opened a similar club, Kandy's Dinner Theater, at a new location.

The newer club, surrounded by auto parts stores, gas stations and fast-food restaurants, is the only establishment in Erie where women performers dance while naked. A lighted sign out front proclaims: ``First Amendment Rights Headquarters.''

A key issue in the Erie case was whether city officials enacted a ``content-neutral'' law against public nudity in general, or whether they specifically targeted nude dancing.

O'Connor said the ordinance was ``on its face a content-neutral restriction that regulates conduct, not First Amendment expression.''

``The ordinance regulates conduct, and any incidental impact on the expressive element of nude dancing'' is minimal, O'Connor said. The requirement to wear G-strings and pasties ``leaves ample capacity to convey the dancer's erotic message,'' she added.

Stevens' dissent contended the ordinance was ``aimed directly at the dancers in establishments such as Kandyland'' and should be held ``patently invalid.''

One issue before the justices had been whether Panos' departure from the scene had made the dispute legally moot, but the court last June denied his attempt to have them declare just that and thereby preserve his state Supreme Court victory.

O'Connor said the case was not moot because the club could reopen and also because the court has an interest in keeping people who won a lower court ruling from seeking to ``insulate a favorable decision from review.''

The case is Erie vs. Pap's A.M., 98-1161.