This is a big week for the coalition of Web giants, activists and trans-partisan activists working to block Internet censorship legislation that could result in the wholesale takedown of user-generated websites. After a weekend of strategizing, organizers working against the Stop Online Piracy Act (SOPA) plan a mass campaign of action to stop advancement of the bill, which will get a markup in the House Judiciary Committee this Thursday.

Fight For the Future, the main organizing hub of the anti-SOPA campaign, has focused on driving supporters to call Congress this week. They have an automated system that connects you to your Congressional office using your zip code. A more street-theater campaign at American Censorship allows supporters to redact any portion of their user-generated content, be it a tweet, Facebook post or blog entry. That redaction then links back to American Censorship to generate more calls.

Employees at Internet companies are encouraged to visit I Work for the Internet and upload their photos and share their stories of how their jobs are threatened by the legislation, which could be used to shut down websites if the authorities find them to include copyrighted content.

The anti-SOPA campaign got a big boost today when eminent legal scholar Laurence Tribe pronounced the bill unconstitutional.

Laurence Tribe, a constitutional law expert at Harvard Law School, argues the Stop Online Piracy Act (SOPA) violates the First Amendment in a memo sent to members of Congress on Thursday.

The bill would empower the Justice Department and copyright holders to demand that search engines, Internet providers and payment processors cut ties with websites “dedicated” to copyright infringement.

Tribe argues the bill amounts to illegal “prior restraint” because it would suppress speech without a judicial hearing.

Additionally, the law’s definition of a rogue website is unconstitutionally vague, Tribe writes.

“Conceivably, an entire website containing tens of thousands of pages could be targeted if only a single page were accused of infringement,” Tribe writes. “Such an approach would create severe practical problems for sites with substantial user-generated content, such as Facebook, Twitter, and YouTube, and for blogs that allow users to post videos, photos, and other materials.”

This matches the activist response to SOPA almost entirely. Websites that allow user-generated content would have no ability to meet with the regulations in the law, policing their millions and millions of bits of content they receive every hour. Web sites could be blocked by the government without a hearing if a content producer accuses them of infringing on their copyright. Search engines and link-backs could be disabled as well. And those eventually found guilty of copyright infringement could spend up to 5 years in prison. Having Tribe enter this debate on the side of the activists is a big victory for the movement.

The community seeks to use the tools of the Internet to stop a campaign that would police and potentially disable those tools. This is a big moment for the online activism community.