On the heels of a Zogby public opinion poll that revealed 58 percent of West Coast voters believe marijuana should be taxed and regulated like alcohol, Assemblyman Tom Ammiano has introduced a bill that would do just that here in California.

At a press conference to announce the bill, Ammiano, a San Francisco Democrat, explained the measure by saying that in the midst of this economic crisis, "the move toward regulating and taxing marijuana is simply common sense." The argument is a natural one. Whatever one ultimately thinks about the issue, a tax-and-regulate system would certainly yield significant amounts of money for California taxpayers in combined revenue and savings.

Marijuana is the state of California's No. 1 cash crop, worth as much as $14 billion a year by some estimates. Under the current system, the state does not capture any tax revenue from that market, which is left in the hands of increasingly violent Mexican drug cartels. By taxing and regulating marijuana, not only would the state generate much-needed revenue, but the market would be turned over to legitimate businesses and the cartels would lose a major source of income.

Of course, generating tax dollars and making life a little tougher for the drug cartels are all well and good, but these benefits wouldn't necessarily justify legalizing marijuana if there were countervailing costs. After all, legalizing robbery might also cut down on police and prison spending, but that doesn't mean it's a good idea.

Even if we weren't facing an economic crisis and Al Capone-style prohibition cartels at the border, ending the charade of marijuana prohibition would be the right thing to do. Frankly, the idea that something 42 percent of all Americans, including the three most recent presidents, have admitted to doing is still illegal is almost surreal.

Marijuana is less addictive, significantly less toxic, carries far fewer negative health consequences, and is less likely to make its users aggressive or violent than alcohol. Indeed, by far the greatest harm associated with marijuana is that you can be arrested for possessing it.

The rarely acknowledged truth is that 40 years into the "war on drugs," only the fringes of the "Reefer Madness" set continue to believe that adults who choose to use marijuana in the privacy of their own homes deserve to be imprisoned for it.

Yet, last year we arrested a record number (872,721) of our fellow citizens for marijuana violations. Why? To "send the right message" to kids.

This is a serious and important concern. There can be no doubt that protecting young people from the dangers of substance abuse should be a chief consideration in debating and designing our drug policies. But, at least in the case of a widely available substance such as marijuana, this consideration also weighs against blanket prohibition.

The fact is that a carefully regulated market would do a much better job of keeping marijuana out of the hands of young people than prohibition. How do we know this is the case?

For starters, because kids consistently report that it is easier for them to buy marijuana than alcohol, according to the National Center for Addiction and Substance Abuse's annual survey. Similarly, in California, more middle and high school students say that marijuana is easier to obtain than even cigarettes.

Comparing teen use rates in the United States with rates in the Netherlands, where marijuana is openly bought and sold in coffee shops, provides even more evidence for this point. Nearly three times as many teens under the age of 15 have tried marijuana in the United States (20 percent) than in the Netherlands (7 percent), according to a comprehensive 2008 report by the World Health Organization.

These numbers may seem counterintuitive at first glance but the reason for them can be distilled down to one common-sense truth: drug cartels don't ask for ID but well-regulated legitimate businesses do. As a result, taking the marijuana market away from the cartels and putting it into the hands of lawful business owners would allow California to more effectively limit young people's access to marijuana through strict and sensible regulations. You can bet that, unlike the member of a street gang, a legitimate business owner subject to imprisonment and the loss of their license would think twice before selling marijuana to a 15-year-old.

This is not to say that Ammiano's bill is necessarily the approach we should adopt. There is wide room for debate about the best system for controlling marijuana. Highly regarded drug policy expert and UCLA professor Mark Kleiman, for example, favors a policy that would make it legal for adults to grow, possess and use marijuana but remain illegal to sell it.

Whatever policy one prefers, however, one thing is certain: With nearly six in 10 West Coast voters in support of a tax-and-regulate system and mounting evidence that our current approach is wasteful, unjust and ineffective, the time to reevaluate marijuana prohibition has come in California.

Kreit is an assistant professor and director of the Center for Law and Social Justice at Thomas Jefferson School of Law in San Diego. 

Opposing view: California Does Not Need Any More Marijuana Users (April 3, 2009)