A federal judge has knocked out a key argument advanced by the recording industry in its battle against illegal file sharing—that consumers can be held liable for simply making copyrighted content available online, even if no one downloads it.

In his decision Tuesday, District Court Judge Neil Wake in Phoenix rejected the industry's "making available" argument, dealing a major blow to the industry's legal strategy as it pursues illegal file swappers.

Wake made his ruling while denying the Recording Industry Association of America's motion for summary judgment, forcing the group to try to make its case at trial.

"[The Copyright Act of 1976] is not violated unless the defendant has actually distributed an unauthorized copy of the work to a member of the public," Wake wrote in his decision. "Merely making an unauthorized copy of a copyrighted work available to the public does not violate a copyright holder's exclusive right of distribution."

The R.I.A.A. sued Pamela and Jeffrey Howell of Scottsdale, Arizona, for copyright infringement in 2006 after the industry's private investigator, MediaSentry, remotely detected 54 copyrighted songs in a publicly available folder on the Howells' computer.

The R.I.A.A. asserts that because the Howells, who are representing themselves in the case, used the file-sharing program Kazaa to make copyrighted works available, they're guilty of infringement, despite the fact that no one—except MediaSentry—ever downloaded the content at issue.

Jeffrey Howell has acknowledged that he had used Kazaa, but said the songs discovered by MediaSentry were copies made for "private use" from his compact-disc library. Kazaa software had automatically placed them in the Kazaa shared folder.

Fred Von Lohmann, a staff attorney at the Electronic Frontier Foundation, a nonprofit digital advocacy group that filed a brief in support of the Howells, called the ruling "a big victory."

"In its order, the court delivers the most decisive rejection yet of the recording industry's 'making available' theory of infringement (i.e., if someone could have downloaded it from you, you've violated copyright, even if no one ever did)," Von Lohmann wrote in a blog post.

A spokesperson for the R.I.A.A., meanwhile, criticized the ruling.

"This is a strange decision that is outside of the mainstream and inconsistent with countless court rulings on these issues," R.I.A.A. spokesperson Cara Duckworth said in a statement. "We are currently considering all options going forward."