Mark Kleiman suggests decriminalization of marijuana. Kleiman proposes that marijuana should be allowed to be grown, possessed, used and given away but not be allowed to be sold.
It would be illegal to sell cannabis or to exchange it for anything of value, but not to grow it, possess it, use it, or give it away. I don’t imagine that the law would effectively prevent sales, any more than anti-gambling laws suppress private poker games. The goal would be to prevent marketing.
My bet would be that, in the short-to-medium run such a policy would have only slight impacts on use, mostly in the form of leading some users who now cease marijuana use as they enter the workforce to continue smoking. Longer-term, I’d expect some, probably modest, growth in use due to decreased social stigma and employment risk; how much of that growth in use would be among people who then got into trouble with the drug is harder to guess. Overall, a pretty small price to pay for eliminating a big illicit market and several hundred thousands of arrests for using, and tens of thousands of prison and jail terms for dealing, per year.
Kleiman argues against the sale because he is aftaid it will be marketed towards children,i.e. Joe Camel. Legalization would be better than decriminalization but would clearly be an improvement over our situation of drug prohibition.