WASHINGTON — Online piracy costs U.S. copyright owners and producers billions of dollars every year, but legislation in Congress to block foreign Internet thieves and swindlers has met strong resistance from high-tech companies, spotlighted by Wikipedia’s protest blackout on Wednesday, warning of a threat to Internet freedom.

House and Senate bills that once seemed to be on a path toward approval now face a rockier future. House Speaker John Boehner on Wednesday said it was “pretty clear to many of us that there is a lack of consensus at this point.”

Here are some of the some of the questions being raised about the bills being considered:

Q. Why is legislation needed?

A. There’s no argument that more needs to be done to protect artists, innovators and industries from copyright thieves and shield consumers from products sold on the Internet that are fake, faulty and unsafe. Creative America, a coalition of Hollywood studios, networks and unions, says content theft costs U.S. workers $5.5 billion a year. The pharmaceutical industry loses billions to Internet sellers of drugs that are falsely advertised and may be harmful.

Q. What is Congress trying to accomplish?

A. The two main bills are the Protect Intellectual Property Act, or PIPA, in the Senate, and the similar Stop Online Piracy Act, or SOPA, in the House. There are already laws on the books to combat domestic websites trafficking in counterfeit or pirated goods, but little to counter foreign violators.

The bills would allow the Justice Department, and copyright holders, to seek court orders against foreign websites accused of perpetrating or facilitating copyright infringement. While there is little the United States can do to take down those websites, the bills would bar online advertising networks and payment facilitators such as credit card companies and PayPal from doing business with an alleged violator. It also would forbid search engines from linking to such sites.

The original bills would have let copyright holders and Internet service providers block access to pirate websites. Critics and Internet engineers complained that would allow copyright holders to interfere in the behind-the-scenes system that seamlessly directs computer users to websites. They said that causing deliberate failures in the lookup system to prevent visits to pirate websites could more easily allow hackers to trick users into inadvertently visiting websites that could infect their computers. The White House also took issue with that approach, saying “We must avoid creating new cybersecurity risks or disrupting the underlying architecture of the Internet.”

Responding to the critics, House Judiciary Committee Chairman Lamar Smith, R-Texas, said he is taking the blocking measure out of his bill. Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., also is reworking his bill to address those cybersecurity issues.

Q. What are other concerns with the bills?

A. Critics say they would constrain free speech, curtail innovation and discourage new digital distribution methods. NetCoalition, a group of leading Internet and technology companies, says they could be forced to pre-screen all user comments, pictures and videos — effectively killing social media. Search engines, Internet service providers and social networks could be forced shut down websites linked to any type of pirated content.

In addition, critics contend that young, developing businesses and smaller websites could be saddled with expensive litigation costs. And, they contend existing rights holders could impede new investment in the technology sector.

Q. What is the status of the bills?

A. Momentum for the bills has slowed, giving the edge to Silicon Valley over Hollywood. The Senate, as its first major business when it returns to session next Tuesday, is to vote on whether to take up the bill. Sixty votes are needed to clear that legislative hurdle. It’s unclear whether supporters have the votes.

In the House, Judiciary Committee Chairman Smith said his panel would resume deliberations on SOPA in February. Meanwhile, Rep. Darrell Issa, R-Calif., chairman of the House Oversight and Government Reform Committee and an ally of the high-tech industry, said he had received assurances from GOP leaders that anti-piracy legislation would not move to the House floor this year unless there is a consensus on it.