WITH the approval of 80% of its voters, Oakland last month became the first city in America to exact a sales tax on cannabis. Los Angeles, San Francisco and other Californian cities may follow along. It is a sign of harsh budgetary times. Although Californians have been allowed since 1996 to buy cannabis for medicinal purposes, only a state sales tax was later added to their purchase, not a local one too. Now, at any rate in Oakland, consumers will have to pay both.

Cannabis sellers claim to be pleased. “We completely support the taxes. It's one step closer to legitimising the business,” says Richard Lee, a local retailer. And, indeed, the case for buying the stuff without a doctor's prescription is gaining ground. Barack Obama has said that the federal government would not interfere with a state's right to regulate the drug. This opened the door for Tom Ammiano, a Californian assemblyman, to introduce a bill earlier this year that would legalise the cultivation of marijuana and its distribution and sale to people over 21.

The California Board of Equalisation, the state's revenue agency, calculates that if Mr Ammiano's bill gets through, the tax receipts could be almost $1.4 billion a year. On top of that, say supporters, there would be lots of cannabis-driven tourism.

There is another side to it, of course. A study by the Substance Abuse and Mental Health Services Administration found that among those seeking treatment for drug and alcohol addiction, the number of cannabis addicts rose from 12% in 1997 to 16% in 2007. The rise is blamed in part on the weed being more potent than it used to be. The National Institute on Drug Abuse says it is up to five times stronger than it was in the 1970s. But, compared with other drugs, cannabis is still relatively benign—and the thought of that extra tax revenue tempts hard-up California.