As far as Harvey Rosenfield is concerned, David had it easy against Goliath - at least David had a sling and five stones.

Rosenfield started with only a few dollars and a cause in a fight against the California insurance industry and ended up a giant slayer with his Proposition 103 ballot initiative to roll back insurance rates more than 20 percent.The Ralph Nader protege said the initiative's victory in Tuesday's election amounted to a voter revolt, with the message that consumers will no longer tolerate high insurance rates and ineffective politicians.

"This proves that you can fight city hall and win," he said in his apartment Saturday. "We've proven that word of mouth and a grassroots campaign is far more powerful than all the slick 30-second TV ads that money can buy."

The insurance industry, which watched its $70 million campaign go down the drain, immediately took its battle to the courts amid threats to pull out of California and predictions of economic doom.

The state Supreme Court temporarily froze the rate rollbacks for motorists, businesses, homeowners and municipalities until it can decide if the measure is constitutional.

The prospect of another long and costly battle to implement Proposition 103 left Rosenfield with little time to celebrate, but he said he's confident that the movement he launched in 1986 will be victorious in the end.

"Just like Proposition 13, the taxpayer rebellion that started in California and spread through the nation, Proposition 103, the voter revolt to cut insurance rates, will sweep the United States like a prairie wildfire," he said.

Rosenfield, 36, announced the drive to put Proposition 103 on the ballot in November 1986 after an unsuccessful attempt to push insurance reform through the Legislature.

Rosenfield has been a staff attorney for Nader's Public Citizen Congress Watch in Washington, D.C., and director of the California Public Interest Research Group.