A US federal appeals court today struck down COPA, the Child Online Protection Act, a Clinton-era censorship law that the Justice Department has been struggling to get implemented for a decade. (The ACLU filed suit as soon as COPA was signed in 1998 and won an immediate injunction.) The battle has made it to the Supreme Court twice, and the DoJ has essentially never gotten any satisfaction out of the courts. This was the case for which the DoJ famously went trolling for search histories. In the ruling issued today, the 3rd US Circuit Court of Appeals upheld a lower-court ruling that COPA violates the First Amendment because it is not the most effective way to keep children from visiting adult Web sites. The law would require sites to check visitors' ages, e.g. by taking a credit card, if the site contained any material that is "harmful to minors," whatever that means.