The federal government weighed in on the closely watched case against Napster Inc. for the first time, saying the music-sharing service is not protected under a key copyright law, as the company claims. In briefs to the U.S. 9th Circuit Court of Appeals, lawyers for the U.S. Copyright Office said Napster has "no possible defense" against claims by the recording industry that it facilitates widespread copyright infringement. The agency, whose position is not binding, sided with U.S. District Judge Marilyn Hall Patel, who in July ruled for the industry, finding that Napster is contributing to widespread copyright infringement in violation of the 1992 Audio Home Recording Act. The Recording Industry Assn. of America filed court briefs that backed the government's position.