The American Civil Liberties Union, Free Press and the Save the Internet campaign have made it clear that the Stop Online Piracy Act poses a genuine threat to human rights advocacy and whistleblowing on the web.

Yet, the measure continues to advance in the US House, even as a Senate variation on it, the Protect IP Act, has been put on hold by Oregon Democrat Ron Wyden.

That’s why Internet sites have been going dark in protest today.

If the bill is stopped, it will be by political action. But that won’t be easy. Powerful lobbies, including Rupert Murdoch’s still considerable and influential DC operations, are backing it.

The only way that members of Congress, especially top Republicans in the US House who tend to defer to Murdoch and Fox News, will oppose SOPA is if they recognize that they could be threatened politically if they take the wrong position on the further of the Internet.

Is that possible? Yes, Indeed, in at one remarkable case, the message has already been sent—and received.

Congressman Paul Ryan, the Wisconsin Republican who chairs the House Budget Committee, has broken with House Republican leaders to express explicit opposition to the legislation.

Why? Is Ryan a champion of Internet freedom and civil liberties? Not hardly.

He was a big backer of the Patriot Act and has never distinguished himself as anything other than a rubber stamp for the demands of corporate interests that would love to colonize the Internet.

So what happened?

Ryan’s Democratic challenger in the 2012 election, an energetic local official named Rob Zerban, made the issue unavoidable for Ryan.

He came out strong against the issue, launched an online petition urging Ryan to join him in opposing it and began working with the powerful online community Reddit—where the registered users submit content—to highlight his fight on the issue.

Zerban kept talking about SOPA when most other pols were avoiding the issue—or simply were unaware of it.

“SOPA is a complex issue but here is how I approach it: the first thing to remember is that our free speech is our most fundamental right as Americans and this is critical to our society and economy. It is also critical to innovation and this process of free speech, which we are doing right now on reddit, is what enables us to share and develop the ideas that impact the world,” said Zerban, a successful businessman, who bluntly declared: “We need to preserve the free nature of the Internet.”

Zerban’s campaign took off as he focused on the SOPA fight. “Since I came out against the overreach of SOPA, we have had an incredible outpouring of support across the Internet,” he explained in an e-mail to the Betabeat website, which has done a terrific job of covering these issues. “Donations are spiking and people are going to www.robzerban.com in much greater numbers. To me, it reflects the power of the Internet as a tool for democracy and that is what I love so much about it and what to make sure we protect.”

Ryan got the message. He issued a terse statement in late December that announced: “The internet is one of the most magnificent expressions of freedom and free enterprise in history. It should stay that way. While H.R. 3261, the Stop Online Piracy Act, attempts to address a legitimate problem, I believe it creates the precedent and possibility for undue regulation, censorship and legal abuse. I do not support H.R. 3261 in its current form and will oppose the legislation should it come before the full House.”

That made Ryan—along with Texas Congressman Ron Paul—one of the most prominent Republicans to oppose SOPA.

“This is an extraordinary victory,” declared Zerban. “Reddit was able to force the House Budget chair to reverse course—shock waves will be felt throughout the establishment in Washington today—other lawmakers will take notice.”

At the least, Democratic challengers should take notice. Zerban has created a model for raising issues and forcing powerful members of the Republican establishment in Congress to take notice.

And Zerban is not backing down.

While Ryan’s official and campaign websites were “up” Wednesday, Zerban’s features this “site off-line” announcement:

My campaign website is down today in support of the online community and those in my district who value the future of the free Internet and who oppose SOPA (the Stop Online Piracy Act) as well as PIPA (the Protect-IP Act). SOPA and PIPA are dangerous pieces of legislation that undermine our fundamental right of free speech. The free nature of the Internet makes it the collaborative and inventive tool that has become; a critical engine of social and economic innovation. Allowing private censorship of the Internet is misguided. There are better ways to achieve the goals of this legislation that do not threaten the essence of the Internet. To learn more, please visit AmericanCensorship.org. I encourage you to take action on this issue: Contact your Representative and Senators to urge them to vote against SOPA and PIPA, find their information at http://www.govtrack.us/congress/findyourreps.xpd Or you can sign a petition by copying this URL into your browser http://act.boldprogressives.org/survey/survey_sopa_reddit/

To learn more about efforts to get Congress to block SOPA, visit the site of the Save The Internet coalition (a group with which I have long been associated and am proud to support) at www.savetheInternet.com.

Follow John Nichols on Twitter at @NicholsUprising