The U.S. Stop Online Piracy Act (SOPA), which would allow U.S. authorities to seize the domain names of copyright-infringing websites, has taken another blow as a leading proponent has withdrawn its support. The Business Software Alliance (BSA), which initially supported SOPA, has decided the legislation goes too far.

"Valid and important questions have been raised about the bill. 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," BSA president and CEO Robert Holleyman wrote on the BSA blog.

SOPA would enable the U.S. government to block access to websites internationally.

"To fix this problem, 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. 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," he added.

Last Friday the European Parliament added its voice to those calling for SOPA to be abandoned, which includes industry leaders Googlem Facebook, Yahoo! and Microsoft.