Despite a procedural glitch, backers hailed the committee’s action as historic because it represented the first legislative approval of the proposal.

“This vote marks the formal beginning of the end of marijuana prohibition in the United States,” predicted Stephen Gutwillig, California state director of the Drug Policy Alliance, a pot legalization group.

The legislation would allow those who are at least 21 years old to possess up to an ounce of marijuana for recreational use. Assemblyman Tom Ammiano (D-San Francisco), author of the measure, said it would provide needed revenue for the state as well as regulation of the drug.

Existing law “is harming our youth,” Ammiano said. “Drug dealers do not ask for ID.”

It is estimated that the proposed $50 tax on each ounce of marijuana sold, along with license fees charged to cultivators, would generate $1.3 billion a year to be used to pay for drug education and treatment.

Ammiano said his bill is not expected to get a required hearing by a second committee in time to meet a Friday deadline. He said he plans to reintroduce the legislation if a similar initiative proposed for the November ballot is not approved by voters.

The anticipated revenue would not be worth the grief the bill would cause, said Assemblyman Danny Gilmore (R-Hanford), a former assistant chief with the California Highway Patrol.

“We’re going to legalize marijuana, we’re going to tax it and then we’re going to educate our kids about the harm of drugs. You’ve got to be kidding me,” Gilmore said. “What’s next? Are we going to legalize methamphetamines, cocaine?”

The Assembly Public Safety Committee approved Ammiano’s bill, AB 390, on a 4-3 vote.