"Our opposition to legalizing marijuana is grounded not in ideology but in facts and experience," say drug czar Gil Kerlikowske and his five predecessors in a Los Angeles Times op-ed piece that urges Californians to vote against Proposition 19. They argue that voters should listen to them because they are "experts in the field of drug policy, policing, prevention, education and treatment." If this is the best case the experts can make against marijuana legalization, they had better call in the amateurs.

Kerlikowske et al. say it's not true that "legalizing and taxing marijuana would generate much-needed revenue," because everyone will grow his own, thereby avoiding sales and excise taxes. Although "people don't typically grow their own tobacco or distill their own spirits," they say, marijuana is different because it is "easy and cheap to cultivate, indoors or out." If growing pot were as easy as the Six Drug Czars imply, there would not be much of a market for all the books and periodicals that explain how to do it properly. In any case, one could also say that tomatoes are "easy and cheap" to grow, or that beer is "easy and cheap" to brew. I've done both, but I still buy tomatoes and beer in stores. The supply is more reliable and varied, and it's a lot easier. Accounting for the time and effort required to grow tomatoes and brew beer, buying them in the store is cheaper too, even though I have to pay taxes on them.

Kerlikowske et al. also say it's not true that "legalization would allow law enforcement to focus on other crimes." They know it's not true because "an overwhelming majority of police professionals does not support legalizing marijuana." And anyway, "law enforcement officers do not currently focus much effort on arresting adults whose only crime is possessing small amounts of marijuana." The opinions of "police professionals"—especially the ones they express in conversations with the director of the Office of National Drug Control Policy—do not necessarily prove that enforcing marijuana prohibition, which goes far beyond nabbing pot smokers, is a sensible use of law enforcement resources. Instead of making that case, the Six Drug Czars imply that enforcing marijuana prohibition does not require any resources to speak of. Well, they're the experts.

Having disposed of what they take to be the two main arguments for Prop. 19, Kerlikowske et al. offer one against it: Increased consumption of marijuana will lead to "more accidents and fatalities involving drivers under its influence." They cite "a nationally representative roadside survey by the National Highway Traffic Safety Administration" that found "8% of nighttime weekend drivers tested positive for marijuana." They also cite "a 2004 meta-analysis published in the journal Drug and Alcohol Review" that found "between 4% and 14% of drivers who sustained injuries or died in traffic accidents tested positive for delta-9-tetrahydrocannabinol." Since traces of THC can be detected long after its effects have worn off, these studies do not even show that the drivers were impaired by marijuana, let alone that it caused any accidents. While experiments indicate that marijuana impairs driving ability to some extent, the effects are not nearly as dramatic as those associated with alcohol. So to the extent that legal marijuana use displaces drinking, Proposition 19 might actually lead to a net reduction in traffic injuries and fatalities.

[Thanks to Kroneborge for the tip.]