The Stop Online Piracy Act (SOPA) is perceived as such a threat to liberty that one or its leading proponents has withdrawn support.
Robert Holleyman, president and CEO of the Business Software Alliance, says that the bill as it stands goes much too far.
SOPA aims to make it harder for online pirates to profit from their activities, and allows the authorities to sieze the domain names of offenders. It would allow the US government to block access to websites worldwide - including those that don't fall under US jurisdiction.
It's been widely criticized - not least by the European Parliament - and more than 60 civil rights organizations have called for it to be scrapped.
"Valid and important questions have been raised about the bill," he says on the BSA blog.
"It is intended to get at the worst of the worst offenders. As it now stands, however, it could sweep in more than just truly egregious actors."
Holleyman says that the BSA is prepared to work with the Judiciary Committee to improve the terms of the bill'
"Definitions of who can be the subject of legal actions and what remedies are imposed must be tightened and narrowed. Due process, free speech, and privacy are rights cannot be compromised. And the security of networks and communications is indispensable to a thriving internet economy," he says.
"Some observers have raised reasonable questions about whether certain SOPA provisions might have unintended consequences in these areas. BSA has long stood against filtering or monitoring the internet. All of these concerns should be duly considered and addressed."