During a lecture organized by the American Enterprise Institute and the Brookings Institution., Posner criticized a 1998 law extending the duration of U.S. copyrights. He also attacked the Patent and Trademark Office for granting "very questionable" business method patents.

"These rights keep expanding without any solid information about why they're socially beneficial," Posner said. "At the same time that regulations are diminishing, intellectual-property rights are blossoming--(two) opposite trends bucking each other."

Posner's critique is significant because up to now much of the attack on the steady expansion of intellectual-property rights has come from the left, and the Seventh Circuit judge is a darling of the conservative movement. Posner, a prolific author, is most famous for applying economic analysis to the law. He also mediated settlement talks in the Microsoft antitrust case.

In his speech, Posner warned that Hollywood studios and other entertainment companies that lobbied for the 1998 Copyright Term Extension Act could be fouling their own industry by reducing materials in the public domain.

"Intellectual property is both the input and output of the intellectual-property industry," Posner said. "The public domain--we don't think much of it. We don't think of it as a major source of societal wealth."

The CTEA is currently under review by the Supreme Court.

Posner said that disturbing growth in overly broad business method patents is due both to the Patent and Trademark Office and a special federal court that hears patent cases.

"A specialized court tends to see itself as a booster of its speciality," Posner said. "Patents are clogging retail commerce on the Internet, and software (patents) in particular are apparently impediments to software development."

Posner praised Stanford University law professor Larry Lessig for challenging the CTEA and locating a sympathetic plaintiff, Eric Eldred, who was harmed when the law took effect.

"There were plenty of eccentrics who were willing to step forward," Posner said. "They wear the 'Free Mickey Mouse' T-shirts and all that."

In a sign that the political situation on Capitol Hill may be shifting slightly, Reps. Rick Boucher, D-Va., and John Doolittle, R-Calif., introduced a bill last month that would repeal key sections of the controversial 1998 Digital Millennium Copyright Act.

Supporters of broader intellectual-property rights argue that longer protections increase the incentive to be creative, and they say Congress is well within its constitutional authority when extending copyright's duration.