Last week the House of Representatives overwhelmingly passed the Cyber Intelligence Sharing and Protection Act despite opposition from civil liberties groups and a threatened White House veto. But a powerful Democratic Senator has signaled his opposition to the measure, making passage in the upper chamber unlikely.

Sen. Jay Rockefeller (D-WV) chairs the Senate Commerce Committee and also holds a seat on the Senate Select Committee on Intelligence. He called the bill's goals "important" but said its "privacy protections are insufficient," according to US News and World Report.

CISPA is controversial because it would grant companies that share information related to online threats broad immunity from liability. Critics fear that it would gut other laws, such as the Wiretap Act and the Stored Communications Act, that protect consumers' privacy. Opponents argue that Congress should take a more targeted approach, revising individual laws that hamper information sharing rather than granting companies broad immunity for violating any of them.

That approach appears to have support among Senate Democrats. "We're not taking [CISPA] up," a representative of the Senate Commerce Committee told US News and World Report. Instead, the committee will be starting over with fresh legislation that will include stronger privacy protections.

Recent events have been a virtual replay of last year's debate over Internet security legislation. The House passed an earlier version of CISPA exactly one year ago today, but a Senate filibuster killed a proposal by Sen. Joe Lieberman (I-CT) in the Senate.