Congress' efforts to muzzle pornography on the Web were dealt another serious setback on Thursday, when a federal judge ruled a 1998 law was unconstitutional and violated Americans' First Amendment rights.

U.S. District Judge Lowell Reed in Philadelphia permanently barred prosecutors from enforcing the Child Online Protection Act, or COPA, saying it was overly broad and would undoubtedly "chill a substantial amount of constitutionally protected speech for adults." The lawsuit was filed by the American Civil Liberties Union.

Even though politicians enacted COPA nearly a decade ago as part of an early wave of Internet censorship efforts, the courts have kept it on ice and it has never actually been enforced. The law makes it a crime for commercial Web sites to make "harmful to minors" material publicly available, with violators fined up to $50,000 and imprisoned for up to six months.