Not so fast, said opponents led by the American Civil Liberties Union, who pointed out that the high court retained a 3 1/2-year-old injunction blocking the law.
"I would have preferred that the Supreme Court voided the law today, but from my clients' perspective, nothing has changed. This law cannot be enforced," said Stefan Presser, legal director of the Pennsylvania ACLU.
Deciding 8-1 on a single, narrow issue, the high court said the law passed a constitutional free-speech test by relying on "community standards" to determine if online material is harmful to minors.
The court, however, left open the possibility that the law remained vulnerable on other grounds that the court did not review, such as the claim by its critics that the measure is unconstitutionally vague.
The majority opinion was written by Justice Clarence Thomas, though other justices weighed in with concurring opinions.
Only one justice, John Paul Stevens, said the law should be thrown out at once. He noted that it could force all Web sites to comply with the standards of the nation's most puritanical community.
The government "has a compelling interest in protecting minors," Stevens wrote in a dissenting opinion. "In the context of the Internet, however, community standards become a sword, rather than a shield."
The Child Online Protection Act, signed into law by President Bill Clinton in October 1998, would make it a crime for a commercial Web site to knowingly place material deemed harmful to children within their easy reach on the Internet. Penalties include fines up to $50,000 and jail terms up to six months per violation.
Congress approved the law after its predecessor, the Communications Decency Act, was struck down by the Supreme Court as unconstitutional in 1997.
