The DOJ-requested court orders could also bar search engines from linking to the allegedly infringing sites.
Other opponents of SOPA and PIPA seem a bit more optimistic about derailing the bills. While some powerful entertainment and content groups support the bills, "on the other hand, you have everybody else, including millions of Americans," said Michael Petricone, senior vice president of government affairs at the Consumer Electronics Association, a large trade group opposed to the bills.
Opposition is growing because U.S. residents are hearing that the bills would hurt the Internet, Petricone added. "There are plenty of people in both the House and Senate that are doubting the wisdom of the bills," he said.
The bills have hit a couple of speed bumps in recent weeks. Giant domain-name registrar Go.Daddy withdrew its support for SOPA after threats of a customer boycott, and the Heritage Foundation, a conservative think tank that has defended tough copyright laws in the past,
"The federal government needs to protect intellectual property rights," wrote James Gattuso, senior research fellow in regulatory policy at the foundation. "But it should do so in a way that does not disrupt the growth of technology, does not weaken Internet security, respects free speech rights, and solves the problem of rogue sites."
In addition, since Dec. 18, more than 46,000 people have signed a WhiteHouse.gov petition calling for President Barack Obama to veto SOPA. A second petition, calling for Obama to stop PIPA, has generated more than 51,000 signatures since Oct. 31.
The Obama administration has promised to issue an official response to all petitions that generate more than 25,000 signatures within a month.
Opponents of the bills are waiting for the White House's official position, said Heather Greenfield, spokeswoman for the Computer and Communications Industry Association (CCIA), a tech trade group opposed to both bills.
The White House "has responded to petitions about alien life on earth, so we imagine they'll respond to the ones about SOPA, too," she said.
CCIA is also encouraged that House Judiciary Committee Chairman Lamar Smith, a Texas Republican and main sponsor of SOPA, has promised to hold a hearing on the cybersecurity implications of the bill, Greenfield said.
"We're optimistic that if members really understood the Internet architecture and cybersecurity measures, they would not support SOPA as written," she added. "Instead, members who are really committed to combatting online piracy would look for effective ways to do that without compromising cybersecurity or the open architecture of the Internet."
Lammakers continue to hear from opponents of the bills, she said. "Members of Congress say their phones are ringing with calls from thousands of Internet users who are furious Congress plans to censor and regulate the Internet -- ahead of understanding what they're doing," she said. "So this could be the netroots issue, and it's hard to say yet how that's going to impact support."
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