Tech companies, digital rights advocates, Internet engineers and law professors rallied on Wednesday against a pending House bill that would allow the government to target “rogue” sites.

The bill would “expose law-abiding U.S. Internet and technology companies to new uncertain liabilities, private rights of action, and technology mandates that could require monitoring of Web sites and social media,” Google attorney Katherine Oyama testified before a House panel on Wednesday at a hearing about the Stop Online Piracy Act.

The proposed Stop Online Piracy Act would allow government officials and content owners to seek court orders banning ad networks and payment processors from doing business with rogue sites -- defined as sites dedicated to infringement. The measure also provides for court orders banning search engines from returning certain results, and prohibiting Internet service providers from putting traffic through to certain URLs -- even if ISPs did so, users could still reach their destinations by typing in the numeric IP addresses.

Hollywood backs the bill, arguing that the measure is needed to stop companies that are outside the jurisdiction of the U.S., and therefore need not comply with the Digital Millennium Copyright Act's take-down provisions, from profiting by infringement.

“The Stop Online Piracy Act recognizes that to effectively stop online theft, every member of the Internet ecosystem needs to play a role, including the rights holders who created the content, the Internet Service Providers and search engines that connect consumers to rogue sites, and the advertising networks and payment processors that provide those sites with financial support,” Motion Picture Association of America senior executive vice president Michael O'Leary said in his written testimony.

The bipartisan House bill was introduced last month by Reps. Lamar Smith (R-Texas), John Conyers (D-Mich.), Bob Goodlatte (R-Va.) and Howard Berman (D-Calif.). A companion measure, the Protect IP Act, is pending in the Senate.

Lamar Smith said the bill is needed because the DMCA “provides no effective relief when a rogue Web site is foreign-based and foreign-operated like the PirateBay.”

Smith also took aim at Google, accusing the company of trying “to obstruct the Committee’s consideration of bipartisan legislation.”

He added: “Perhaps this should come as no surprise, given that Google just settled a federal criminal investigation into the company’s active promotion of rogue Web sites that pushed illegal prescription and counterfeit drugs on American consumers,” referring to Google's agreement to forfeit $500 million for allowing Canadian pharmacies to advertise on AdWords in the U.S. “Given Google’s record, their objection to authorizing a court to order a search engine to not steer consumers to foreign rogue sites is more easily understood.”

Conyers, another co-sponsor, also brushed off concerns of Internet engineers that the measure would “break the Internet,” saying that such an outcome was “not likely.” Internet engineers have said that the measure would interfere with the Domain Name System.

Not all lawmakers said they backed the bill. One opponent to the measure, Rep. Zoe Lofgren (D-Calif.), went so far as place a black banner on her home page, to send a message that she believes the bill amounts to censorship.

Advocacy groups like the Electronic Frontier Foundation and Free Press did the same on Wednesday.

A group of law professors led by Mark Lemley of Stanford also sent lawmakers a letter expressing concern that the measure would violate “our core tenets of due process” because it would allow for court orders that could harm sites without first guaranteeing that the operators have a chance to tell their side of the story.

The letter calls the bill “the most ill-advised and destructive intellectual property legislation in recent memory.”

Many companies and advocates who oppose the bill say it could have a devastating impact on sites that host social media. That's because the measure could effectively curb provisions of the Digital Millennium Copyright Act that have protected companies from liability when users' posts infringe on copyright.

Currently, the DMCA's safe harbors provide that Web companies are immune from liability for infringing material posted by users, as long as the companies remove pirated material at the owner's request. But opponents say that the bill could require sites to more actively police user-generated content for infringement.

The measure says that a site can be considered dedicated to infringement if it “fails to confirm” a high probability that it's used for infringing activities. If social networking sites are viewed as likely to host pirated material, then the operators of those sites could be forced to start proactively policing posts in order to avoid the “rogue” label, according to opponents.