A renewed effort in Congress to curb violence on television drew immediate challenges from broadcasters and from a civil rights organization that said the move was a "Trojan horse" that could open the gates for government censorship of TV.

Sen. Paul Simon, D-Ill., and Rep. Dan Glickman, D-Kan., saying there was overwhelming evidence of a link between excessive TV violence and children's behavior, introduced a bill Tuesday that would grant a three-year antitrust exemption to the TV industry so networks, local stations, the cable industry and producers could formulate voluntary guidelines on TV violence.The bill is identical to a measure that Simon and Glickman offered unsuccessfully last year.

The National Association of Broadcasters and the American Civil Liberties Union said the bill raised serious First Amendment concerns.

ACLU legislative counsel Barry Lynn labeled the bill "a Trojan horse to bring the government into the business of regulating the content of television broadcasting and cable."

"There is nothing voluntary about guidelines which emerge from a regulated industry after Congress has instructed it about specific programming it finds objectionable," he said.

NAB spokeswoman Susan Kraus said, "Can it ever be truly voluntary when you have the government breathing down your neck?"

She said that although the government "can insulate the industry from antitrust actions, it cannot insulate us from being sued on First Amendment grounds."

Simon said he did not intend to censor television or circumvent First Amendment protections for free speech.