Anti-abortion protesters won a major victory at the U.S. Supreme Court Wednesday.

The high court ruled that federal laws initially designed to stop racketeering and organized crime cannot be used to punish aggressive anti-abortion demonstrators.

The court's majority opinion was written by Chief Justice William Rehnquist. He says that while the protest activity at abortion clinics has been disruptive at times, it does not qualify as extortion under federal law. Only one of the high court's nine justices dissented from the opinion.

The ruling is a victory for abortion opponents, especially a group called Operation Rescue. They were under a nationwide court order to stop interfering with abortion clinics by blocking entrances and harassing staff.

Wednesday's Supreme Court ruling lifts that nationwide injunction.

Operation Rescue leader Joseph Scheidler says the decision means his group will now step up its anti-abortion protests.

"That is basically what this case was 'are we allowed to protest something we consider a grave injustice or not?'" he said.

Abortion rights groups say they fear the court ruling will encourage anti-abortion activists to become more aggressive.

Kate Michelman is president of one of the country's leading abortion rights organizations, NARAL (National Abortion and Reproductive Rights Action League) Pro-Choice America.

"This is especially scary in the political landscape where over half of the state legislative bodies are ready to pass virtually any restriction on a woman's access to abortion," she said.

The case began in 1986 when abortion clinics in Delaware and Wisconsin filed suit against anti-abortion protesters. Attorneys for the clinics and for the National Organization for Women wanted abortion protesters prosecuted under racketeering and extortion laws normally used to charge organized crime figures. Conviction under those laws carries harsher penalties and abortion rights activists had hoped the threat of prosecution under those statutes would discourage anti-abortion demonstrators.

Wednesday's Supreme Court ruling applies to all kinds of protests, not just those at abortion clinics.

Legal analysts say the ruling could embolden anti-abortion protesters. But they also note that disruptive protesters could still face prosecution under other laws that carry lesser penalties.