Such confidentiality has marked the entire ACTA process, according to panelists, who called for more transparency in the negotiation of the multilateral intellectual property treaty that can come into effect without Senate ratification, cemented as an "executive agreement." U.S. Trade Representative Ron Kirk and his team have indicated in the past that while they value transparency, keeping the details of the trade deal under wraps is essential.

Beyond broad agreement about the need for transparency, panelists clashed with the single ACTA proponent on the panel over whether the treaty will impact U.S. laws. Steve Metalitz, who represents such copyright stakeholders as the Motion Picture Association of America, predicted that the treaty will "color within the lines" of current U.S. rules since the reality is that "Congress may not be eager to...change the law," he said.

But others on the panel thought such restraint was unlikely. "We can all agree that it would create some constraints on the U.S. government in the future," said Ryan Clough, legislative counsel to Rep. Zoe Lofgren, D-Calif. "That's a serious concern."

ACTA detractors worry the treaty will codify as international norm those pieces of U.S. copyright law that they say are problematic. These include provisions of the Digital Millennium Copyright Act that allow for inadequate "fair use" exceptions for copyrighted material, critics say. They also say leaked information about the content of the treaty suggests it will give service providers too much power to police the Internet.