Ammiano says billions of dollars in the illicit marijuana trade goes up in smoke every year, billions that the state could get by taxing the drug. Treating pot just like alcohol and cigarettes could help balance California's budget.
Kevin Reed is president of the Green Cross medical marijuana dispensary in San Francisco. His pot club, like many others, pays business taxes and his patients pay sales taxes on their purchases. Reed supports Ammiano's bill.
"You know, if it puts me out of business, that's fine with me," Reed said.
Ammiano says marijuana is California's largest cash crop.
"The marijuana industry probably nets in California alone $14 billion," Ammiano said.
The bill is also supported by state Board of Equalization chair Betty Yee. She says the taxes would be a windfall for the state.
"The revenue impact of this proposal we believe will generate over $1.3 billion," Yee said.
Part of that money would come from a $50 per ounce state excise tax on the drug - roughly $1 per joint, according to Ammiano. Sales tax revenue would make up the rest.
Advocates say the bill would take the profits away from drug dealers.
"They are willing to kill for and rob California taxpayers of billions of dollars in potential revenue," Steve Gutwillig said.
San Mateo County District Attorney Jim Fox opposes legalizing pot. He believes the proposed tax will not change the status quo.
"If people are going to have to pay $50 an ounce, you're going to have a black market," Fox said.
The bill also flies right in the face of federal laws, which ban the drug.
The U.S. Drug Enforcement Agency declined to respond to the bill, saying, "We can't make any comments until we get more direction from the federal government. So this is a blanket no comment."
Most people believe the bill's chances of becoming law is a long shot at best, but the "no comment" from the DEA could be a hint the Obama administration is re-thinking federal pot policy and its war with California over the use of medical marijuana.