The government filed a "friend of the court" brief with the 9th U.S. Circuit Court of Appeals in San Francisco, saying that a key part of Napster's defense against the record industry's copyright infringement lawsuit "flouts the terms" of federal copyright law.
The filing came hours before the Recording Industry Association of America (RIAA) filed its own brief in the case, in which the group's lawyers argued that the federal judge's decision, which is on appeal, was correct in finding that the defendant's service fosters massive illegal copying.
"Napster's latest defense is yet another veiled attempt to reinvent itself, its legal position and copyright law," Hilary Rosen, chief executive of the RIAA, said in a statement. "The fact is, the law is on our side. We are not suing a technology. We are suing a company that is stealing work that does not belong to them."
Napster's response to the RIAA's filing is expected Tuesday.
The government's "friend of the court" brief was jointly submitted by the civil division of the Justice Department, the U.S. Copyright Office and the U.S. Patent and Trademark Office.
The agencies wrote that if the file-swapping service is allowed to exist in its current form, "Napster's users would be permitted to engage in digital copying and public distribution of copyrighted works on a scale beggaring anything Congress could have imagined when it enacted the (Digital Millennium Copyright) Act. Yet the music industry would receive nothing in return."
The court is not required to take that brief into account in the same way it will scrutinize the arguments of Napster and the RIAA. Nevertheless, the gravity of federal offices becoming involved in the case could be damaging to Napster's legal interests.
The RIAA's brief filed was expected to cover much of the same ground traveled by both sides in the last eight months. Napster's service contributes to massive violations of industry copyrights and should be shut down or otherwise barred from infringing copyrights, recording industry lawyers have said.
The legal crossfire stems from a court decision in late July, in which U.S. District Court Judge Marilyn Hall Patel granted a preliminary injunction against Napster, ordering that company to block all major-label songs from being traded using its service or to shut down.
Napster quickly appealed that ruling and won a temporary delay while the appeals court reviewed the district court judge's decision.
In its own brief last month, Napster argued that Patel had made serious legal and procedural errors in issuing the injunction.
"The trial court, in its ruling, misunderstood and misinterpreted the standards for contributory and vicarious infringement," Napster attorney Jonathan Schiller said during a conference call after the company's legal brief was filed.
The past month of relative legal quiet has led to some unexpected legal bedfellows.
Late last month, several technology and Internet-focused trade associations filed "friend of the court" briefs that took issue with different parts of Patel's ruling against Napster.
None of these groups, which included the powerful Consumer Electronics Association and the Digital Media Association, explicitly defended Napster's position. But each of the briefs could serve as an argument in the file-swapping company's favor.
Today's brief on behalf of the government will likely serve as a strong counterbalance to those earlier filings, even if none address precisely the same set of issues.
The appeals court has scheduled a date for the two sides to meet in court again in the first week of October.