(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.