The Pirate Bay is a popular Sweden-based file-sharing hub that allows users to share music, movies and other entertainment with others on the Web. It’s also been busted by European authorities for illegal file sharing, and in 2009 four co-founders were convicted by a Swedish court. Yet the site remains online.

Online piracy is big business—rather, big anti-business. Sites that host the sharing of copyrighted material are coming under increasing pressure to police their users. According to a 2007 report by the Institute for Policy Innovation, illegal downloading of music, movies and other intellectual property costs the United States economy $58 billion annually. 

Most losses are attributed to offshore sites that are tough to control. Powerful interests—from Nike to the Motion Picture Association of America to the National Football League—have put their influence behind a bill in Congress that would make such sites invisible inside of the U.S.

That bill, sponsored by Sen. Patrick Leahy (D-Vt.), sailed unanimously through committee and headed for passage until one man stopped it: Sen. Ron Wyden.

Using a "hold"—a Senate parliamentary move he's criticized in the past—the Oregon Democrat tied up Leahy's bill, the Preventing Real Online Threats to Economic Creativity and Theft of Intellectual Property Act, or PROTECT IP. He did the same thing to a similar bill last year.

Oregonians might wonder why Wyden, known widely for his work on health care, is so deeply involved in an Internet issue, standing alone against a bill authored by a powerful member of his own party. 

But many bloggers, tech writers and free-Internet advocates see the efforts of corporations that want to control access as akin to censorship. The technology pirates use to send stolen music, movies and books, for example, is also used to share ideas and documents. Activists worry the proposed controls look too much like those used in countries like China, where the so-called Great Firewall limits what hundreds of millions of people can see online. 

That's made Wyden a hero of sorts with legions of the Net savvy. Although mainstream coverage of the bill has been minimal, it's been widely mentioned on blogs and online media; Wyden's stance gets discussed by the generation that lives on the Internet. It's also won him powerful tech allies such as Google, which is fighting the bill.

"There isn't another lawmaker that's been so much on the vanguard for protecting the Internet itself," says Kevin Bankston, a senior staff attorney for the Electronic Frontier Foundation, a digital-rights advocacy group in San Francisco.

The bill's supporters say Wyden is obstructing a solution aimed at stopping the theft of billions of dollars every year, solving a problem that now costs thousands of American jobs.

Wyden's position has put him in opposition to a wide array of powerful interests—including the U.S. Chamber of Commerce, the AFL-CIO, the Recording Industry Association of America, Comcast, Dolce & Gabbana, and Pfizer, to name a few—who want to stop theft. "Illegal activity is not free speech,” says Hal Ponder of the American Federation of Musicians. 

Wyden also goes up against groups that have long supported him, including unions and Nike, a big campaign contributor. Many of these interests need Wyden on other issues and are careful not to criticize him. (Nike officials declined comment but offered a statement reiterating support for the bill.) 

Not so the Motion Picture Association of America, which has posted a blog, "PROTECT IP: Workers vs. Wyden?"

"It is one thing to say that the Internet must be free; it is something else to say that it must be lawless," First Amendment lawyer Floyd Abrams is quoted as saying on the MPAA's page criticizing Wyden. "Even the Wild West had sheriffs."

Wyden says he's been a champion of Internet freedom for more than 15 years. "I think the Internet is the shipping lane of the 21st century," he says. "The proponents of [the bill] are trying to give law enforcement tools to go after foreign websites. I've got no problem with that, but I've got a problem with the means."

Because the bill seeks to control what Internet service providers, or ISPs, allow to pass through their networks, Wyden says, these Web middlemen might be inclined to muzzle free speech. "Linking is the heart of the Internet's architecture," he says, "and what we have is a bill that would make it very hard to have linking in any kind of effective fashion."

Opponents say the bill would give commercial interests too much power to control the Internet. "Wyden understands the ultimate power the [bill] would place in the hands of private companies, to censor speech and to potentially destabilize the Internet," says Lydia Pallas Loren, a Lewis & Clark Law School professor and expert in intellectual property law.

But backers of the bill believe that ISPs must be held accountable for allowing piracy sites to use their networks.

"The Internet isn't just a bunch of pipes," says Daniel Castro with the Information Technology and Innovation Foundation, an industry-backed group that supports the measure. "There are intelligent intermediaries that are involved in building the Internet we use today. There is responsibility that goes along with that."

Wyden's position strengthens his image as a Net freedom fighter. In tech-savvy Oregon, that's a good image to maintain. 

"I'm sure he didn't make any friends with your Comcasts of the world, or your Vivendis, the big copyright holders, but he certainly won political capital from companies like Yahoo and Google," says Chris Shortell, associate political professor at Portland State University. "That's not necessarily a bad trade-off.”