The SOPA bill and its Senate companion, the Protect IP Act (PIPA), are intended, according to its sponsors and supporters – including the music and film industries – to fight piracy of online content. The bills would, among other things, allow the US Attorney General to seek injunctions against foreign websites that post or sell copyrighted US content. Internet service providers and other online companies would be required to enforce the injunctions by using the domain name system (DNS) to block consumer access to those sites.

Critics argue that the bills would expose online companies to uncertain liability for content judged to violate copyright law. Google Chairman Eric Schmidt has compared the provision requiring online companies to block content to how China censors political speech online.

Leahy said he is preparing an amendment to be considered during the Jan. 24 floor debate on PIPA that would suspend the provision giving law enforcement the authority to require internet companies to block access to foreign websites with infringing content, pending a study of its impact.

“I regret that law enforcement will not have this remedy available to it when websites operating overseas are stealing American property, threatening the safety and security of American consumers. However, the bill remains a strong and balanced approach to protecting intellectual property through a no-fault, no-liability system that leverages the most relevant players in the Internet ecosystem”, Leahy said in a statement.

Sen. Ron Wyden (D-Ore.) said that, while Leahy’s proposed amendment was “welcome news”, it does not eliminate the “clearly identified threat to net security” contained within the bill. “Beyond the DNS provisions, the bill still establishes a censorship regime that threatens speech, innovation, and the future of the American economy. I remain firm in my intent to block consideration of the PIPA bill until these issues are addressed and I am committed to doing all I can to ensure that whatever legislative course is taken, that it is fully transparent, fully understood and fully considered by all those who value the Internet”, Wyden said in a statement.

The House SOPA bill remains stalled in the House Judiciary Committee after contentious debate last month forced the chairman to suspend consideration of the bill.