Excessive harm is caused at both ends of the continuum, where big business flourishes, one within the law and the other outside of it. Both share the goal of profit maximisation from supplying and selling as much of their drug as possible.
The alcohol industry goes out of its way to project a socially responsible image and strives to be seen as part of the solution to problems its product creates rather than ever admit it is central to the problems.
Behind the scenes, however, alcohol corporates target new young customers, avoid paying tax, schmooze politicians, and attempt to denigrate those who point out their devious tactics.
The organised criminal cannabis suppliers also flagrantly target the young and avoid paying tax, but they don't try to pretend they are anything but gangsters making money out of drug dealing.
Leaving recreational drugs in the hands of big business, without very strong regulation, is a recipe for harm maximisation. Prohibition is an admission of defeat and an abrogation of control.
Harm would be minimised in the middle ground of the drug policy continuum if the Government took centre-stage and strongly regulated drugs in terms of marketing, pricing, accessibility, age of purchase and drug-driving laws.
With change in the cannabis laws coming there is danger that a 180-degree switch might occur - from prohibition to commercialisation.
Lobbying of our parliamentarians may already be under way by business leaders salivating at the new fortunes they anticipate reaping. This is especially so since the dramatic changes in the United States where four states now have laws allowing private businesses to supply and sell cannabis.
There are alternatives to a private business model, one of which is the establishment of state-owned enterprises.
Government monopolies of retail sales of alcohol exist in Scandinavia and are documented as a highly effective harm reduction intervention for alcohol . In Uruguay the Government directly controls a legalised cannabis market alongside home growing and social clubs.
With the Government taking control of drugs, the huge profit from sales goes back to the Government for the greater good. Black markets are undermined while health promotion can be genuinely undertaken at the point of sale, motivated by the fact the state bears the costs for harm from excessive use of these drugs.
At the entrance of a Finnish liquor outlet I visited several years ago was a display of educational material about alcohol harm, although it was the absence of ugly alcohol marketing, limited hours of purchase, and the lack of ultra-cheap discounted alcohol that was most impressive.
The continuance of rampant commercialisation of alcohol with the addition of an exuberant privately driven cannabis industry would be the very worst outcome of re-thinking cannabis law.
Professor Doug Sellman is director of the University of Otago's national addiction centre in Christchurch.
