Senate Commerce Chairman Daniel Inouye, D-Hawaii, told CongressDaily in April that he would do his best to move the measure, though he acknowledged constitutional concerns. Rockefeller is a senior member of the committee.

Broadcast industry sources said it is unclear how they would seek to stymie or derail the measure because they haven't seen it.

Legislation previously authored by Rockefeller and Sen. Kay Bailey Hutchison, R-Texas, would require the FCC to study whether parental controls are effective for all forms of television. If not, the agency could curtail excessively violence scenes.

The new version is expected to contain similar language and additional provisions. An industry source said Rockefeller will approach Hutchison about again being a co-sponsor. Rockefeller's office had no comment, and Hutchison's office did not return calls.

Tim Winter, president of the Parents Television Council and a former network TV and Hollywood executive, expressed hope that the entertainment industry would act unilaterally to avoid legislation, which he considers a last resort. "We hope that Congress can stay out of that," he said, adding that the mere threat of government intervention might prompt voluntary action.

Nevertheless, the council believes that broadcasters have strayed from their obligations to serve the public interest and must be reined in, Winter said. Sen. Sam Brownback of Kansas, who is seeking the Republican presidential nod, is on the council's board, while a Democratic presidential hopeful, Sen. Hillary Rodham Clinton of New York, previously has sought to curtail sexually explicit TV content and violent videogames.

Rockefeller's effort faces a growing chorus of opposition from civil libertarians and broadcast industry groups. "We're not against censorship in your home. We're against the government doing it," an American Civil Liberties Union spokeswoman said. The source emphasized that voluntary steps by producers and broadcasters to modify programming are acceptable to the organization.

Noting that two-thirds of U.S. households do not include children, TV Watch Executive Director Jim Dyke said it is unfair to tone down or reschedule shows that adults want to watch in prime time. "Not everything on television is intended for kids," he said during an interview. "The idea that the government needs to take steps because parents can't seems bizarre to me."

The South Carolina-based group represents filmmakers, TV networks, minority groups and other interests.

The last time Congress took major aim at TV violence in the late 1990s, broadcasters managed to stave off legislation by agreeing to a ratings system.