A federal appeals court has ruled that a law meant to safeguard children against Internet pornography is riddled with problems that make it "constitutionally infirm."

A three-judge panel of the U.S. Court of Appeals for the 3rd Circuit ruled Thursday that the Child Online Protection Act restricted free speech by barring Web page operators from posting information inappropriate for minors unless they limited the site to adults. The ruling upheld an injunction blocking the government from enforcing the law.

The court said that the law made it too difficult for adults to view material protected by the First Amendment, including many non-pornographic sites.

Signed by President Bill Clinton and endorsed by President Bush, the law is one of several on Internet decency that courts have struck down.

The American Civil Liberties Union initiated the legal challenge. The Justice Department, which had argued in favor of the law, may ask the 3rd Circuit to rehear the case or appeal to the U.S. Supreme Court.

Previously, the 3rd Circuit had ruled the law unconstitutional on the ground that it allowed the legality of Internet content to be judged by "contemporary community standards." On appeal, the Supreme Court said that evaluation standard alone did not make the law unconstitutional and sent the case back to the 3rd Circuit for further evaluation.

In Thursday's opinion, the appeals court said that in seeking to define material harmful to minors, the law made no distinction between material inappropriate for a 5-year-old and material harmful to someone in his or her early teens.

The judges also said that while the law sought to get around free-speech arguments by making the restrictions apply only to Web operators who posted material for "commercial purposes," it did not address what level of profitability was required.

In addition, the court said screening methods suggested by the government, including requiring Web page viewers to give a credit card number, would unfairly require adults to identify themselves before viewing constitutionally protected material, such as medical sites' sex advice.