People on both sides of the marijuana legalization debate have strong feelings about Proposition 19, the California ballot initiative that promises to regulate, control and tax cannabis. But science and empirical research have been given short shrift in the discussion. That's unfortunate, because the U.S. government has actually funded excellent research on the subject, and it suggests that several widely held assumptions about cannabis legalization actually may be inaccurate. When the total body of knowledge is considered, it's hard to conclude that we should stick with the current system.
One important question is whether laws criminalizing marijuana have effectively reduced supply and use. It would appear from available data that they have not. Despite billions spent on anti-cannabis law enforcement and a 30% increase in the number of arrests in California since 2005, marijuana remains the most frequently used illegal drug. Nationally, an estimated $10 billion is spent each year enforcing marijuana laws, yet an ongoing study funded by the National Institute on Drug Abuse has concluded that over the last 30 years, the drug has remained "almost universally available to American 12th-graders," with 80% to 90% saying the drug is "very easy" or "fairly easy" to obtain.
On the health side of the equation, scientific consensus is that while cannabis may pose some health risks, they are less serious than those posed by alcohol and tobacco. The approach taken to regulating these other harmful substances, however, hasn't been to criminalize them but to regulate their distribution, to impose taxes on their purchase and to educate the public about their risks. These measures have been shown to be effective, as in the case of cigarette consumption, which has dropped dramatically.
On the other hand, cannabis prohibition has not achieved its stated objectives. As detailed in a report published last week by my organization, the International Centre for Science in Drug Policy, research funded by the U.S. government clearly demonstrates that even as federal funding for anti-drug efforts has increased by more than an inflation-adjusted 600% over the last several decades, marijuana's potency has increased by 145% since 1990, and its price has declined 58%.
In this context, supporting Proposition 19 seems like a reasonable position, and recent polls have suggested that almost half of decided voters support the ballot initiative. However, there has emerged a strong assumption in the debate that, though legalization will save police time and raise tax revenue, this will come at the cost of increasing rates of cannabis use.
This notion is based on a widely cited Rand Corp. report, which used a theoretical model to conclude that rates of cannabis use will increase if cannabis is legalized. Though the authors of this report cautioned readers that there were "many limitations to our estimate's precision and completeness" and that "uncertainties are so large that altering just a few key assumptions or parameter values can dramatically change the results," few seem to have read past the headline that legalization is likely to increase cannabis use.
This may be the case, but it's not a certainty. In the Netherlands, where marijuana has been sold in licensed "coffee shops" since the 1970s, about 20% of the adult population has used the drug at some time in their lives. In the United States, where it is largely illegal, 42% of the adult population has used marijuana.
Neither Rand's theoretical model nor other commentaries have considered the potential benefits of the broad range of regulatory tools that could be utilized if the marijuana market were legal. The state could then license vendors, impose purchasing and sales restrictions and require warning labels. Although these methods have been scientifically proven effective in reducing tobacco and alcohol use internationally, it is noteworthy that successful government lobbying by the tobacco and alcohol industries has slowly eroded many of these regulatory mechanisms in the United States.
A bill has been introduced in the California Legislature to create a uniform statewide regulatory system under the California Department of Alcoholic Beverage Control if Proposition 19 passes. Such a system would allow, finally, for an evidence-based discussion of how to optimize cannabis regulatory regimes so that the benefits of regulation (including such things as tax revenue and reduced drug market violence) can be maximized while rates of cannabis use and related harms can be minimized.
Up to now, the fact that cannabis is illegal has meant that the unregulated market has been largely controlled by organized-crime groups, and the trade has sparked considerable violence, both in the United States and in Mexico. Given the widespread availability and use of cannabis despite aggressive criminal justice measures, there is no doubt that a saner system can be created if marijuana is strictly regulated rather than left in the hands of organized crime.
Evan Wood, a physician and professor of medicine at the University of British Columbia, is the founder of the International Centre for Science in Drug Policy.