"There is little evidence that the Act has reduced the production of child pornography or the child sexual abuse associated with its creation," wrote Judge Jan E DuBois, of the US District Court for the Eastern District of Pennsylvania. "On the other hand, there is an abundance of evidence that implementation of the Act has resulted in massive suppression of speech protected by the First Amendment".
The case was brought by the Washington-based Center for Democracy and Technology (CDT) together with the American Civil Liberties Union (ACLU) of Pennsylvania, and Penn state ISP Plantagenet Inc.
Under the controversial Internet Child Pornography Act – the first of its kind in the US the state Attorney General or any county district attorney can unilaterally apply to a local judge for an order declaring that certain internet content may be child pornography, and requiring any ISP serving Pennsylvania to block the content.
However, the claimants argued that, because of technical difficulties, most ISPs can only comply with the order by blocking a large volume of innocent web content as well as target pages. Often this means blocking access throughout an ISP's network, meaning that the Pennsylvanian orders affect internet users throughout the US.
Over one and a half million innocent web sites have been blocked as a result of the Act, the lawsuit claimed.
Pennsylvania State Attorney General Jerry Pappert disagreed, arguing that current technology was sufficiently advanced to be able to block only targeted sites, and that if ISPs were blocking other sites, it was because they were not doing it properly.
On Friday Judge Jan DuBois issued his ruling. "With the current state of technology," he wrote, "the act cannot be implemented without excessive blocking of innocent speech in violation of the First Amendment".
He found that the two alternatives that could reasonably be used by the ISPs in complying with the court order both resulted in the overblocking of web sites – and rejected the blocking method advocated by the State as "infeasible".
According to Judge DuBois, the state administration had not proved that the Act had reduced child abuse or child exploitation and therefore, "the Act suppresses substantially more protected material than is essential to the furtherance of the government's interest in reducing child sexual abuse."
The ACLU welcomed the ruling, which has been watched closely across the US. Several states, including Maryland, have been considering implementing similar legislation.
Sean Connolly, spokesman for the state Attorney General, told Reuters that his office is reviewing the decision to decide whether or not to file an appeal.