The U.S. House of Representatives Judiciary Committee slowly moved toward approval of the controversial copyright enforcement bill Stop Online Piracy Act (SOPA), although the panel was able to debate only about half of the planned amendments to the bill Thursday.

As of 9:15 p.m., the committee, by wide margins, had voted to reject more than 20 amendments meant to address concerns by many members of the technology and civil liberties communities. The hearing will continue into Friday and maybe longer.

The committee rejected an amendment offered by Representative Darrell Issa that would have stripped out controversial provisions in the bill targeting search engines and Internet service providers.

SOPA would allow the U.S. Department of Justice to seek court orders requiring Internet service providers to filter out the domain names and requiring search engines to block the websites that are accused of infringing copyright. Issa's amendment would have killed the provisions related to the domain name system.

Moderating Amendments Rejected

The committee voted 22-12 against the Issa amendment, in a vote that could foreshadow strong support for SOPA in the committee. The Issa amendment would have removed some of the most contentious parts of SOPA, including concerns that the legislation would cause problems with security in the DNS, supporters argued.

If the committee eventually votes to approve SOPA, the legislation would go to the House floor. The legislation would also have to pass through the Senate before going to President Barack Obama for his signature or veto.

SOPA would empower the DOJ and copyright holders to target news sites that link to allegedly infringing sites, Issa said. Once U.S. authorities start blocking links and censoring Web content, "you start a snowball effect to which there is no end," he added.

SOPA's search engine provision would be ineffective, added Representative Zoe Lofgren, a California Democrat. Even if U.S. search engines block links to foreign websites, it would be simple for Web users to find other search engines, she said. "The fact that we would try to disappear a site on a search engine doesn't disappear the site," she said.

SOPA supporters said the other provisions of the bill, which would allow the DOJ and copyright holders to seek court orders blocking payment processors and online advertising networks from doing business with foreign sites accused of infringing copyright, would not be effective enough to fight foreign websites that sell infringing products.

Under U.S. law, there's a "gaping loophole" shielding foreign websites from the reach of the DOJ, said Representative Bob Goodlatte, a Virginia Republican. "While it continues to be a tremendous, transformational medium, the Internet has also made it easier than ever in the history of the world to steal other's ideas and works," he said.

'Rogues' Said Targeted

Representative Lamar Smith, the committee chairman and main sponsor of SOPA, said new action is needed to deal with so-called rogue websites based overseas. "The problem of rogue websites is real, immediate and increasing," Smith said. "It harms companies across the spectrum. And its scope is staggering. The resultant economic losses run into the hundreds of billions of dollars each year."

U.S. residents have the "most to lose" if Congress does not act, because the U.S. produces more intellectual property than any other country, Smith said. More than 400 companies and groups have voiced support for SOPA, supporters said. However, the tech industry organization Business Software Alliance withdrew its support last month, and the European Parliament has expressed concern for the way the legislation addresses the issue.

Opponents of SOPA also listed hundreds of people and groups that have raised concerns.

Late Thursday, the committee voted down an amendment that would require copyright holders to pay all court costs, if the copyright holder loses its legal petition to have an accused website declared a copyright infringer. The committee also rejected an amendment to remove lawsuit protections for ISPs, domain name registrars, payment processors, and other businesses that voluntarily take action against accused websites.

Tech Testimony Rejected

Issa, Representative Jason Chaffetz (R-Utah), and other opponents of SOPA asked Smith to delay the markup of the bill and hold a hearing featuring Internet engineers and their views on whether the bill would harm Internet security. The committee has hosted only one hearing on SOPA, and no engineers or security experts testified, Chaffetz said.

Dozens of Internet security experts have raised concerns about the bill and its effect on implementation of DNSSEC, a set of applications designed to secure the domain name system, Chaffetz said. "Maybe we ought to ask some nerds about what this really does," he said to other committee members. "If you don't know what DNSSEC is, you don't know what you're doing."

There's time to have another hearing, Issa added. Copyright infringement is "not a new problem," he said.

Smith declined to slow the process down. "I have every intention of going forward today, tomorrow and however long it takes," he said.

The markup hearing will continue into Friday and potentially into the new year after the House returns from its holiday break. The committee, faced with more than 60 proposed amendments to the bill, was able to get through fewer than 10 of them by 5:30 p.m. Thursday in a hearing that began at 10 a.m.

At the beginning of the hearing, Lofgren insisted on the committee's clerk reading the entire 71-page substitute amendment offered by Smith late Monday. The public didn't have enough time to digest the amendment before Thursday's hearing began, she said.

The committee didn't vote on Smith's substitute amendment Thursday.

Late in the day, Representative Sheila Jackson-Lee, a Texas Democrat, stirred up controversy when she called a tweet by committee member Representative Steve King, an Iowa Republican, "offensive." King, watching the hearing on television, posted on Twitter that he was so bored by Jackson-Lee's questions that he was "killing time by surfing the Internet."

The committee took about 15 minutes to sort out demands by Republicans that Jackson-Lee take back the word "offensive." She finally did, instead calling King's tweet "impolitic and unkind."

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is grant_gross@idg.com.