So would that imply, Georgiansilver, that keeping it illegal is justified as a way of paying-off the drug barons by protecting their sales, and so reducing to some extent the damage they might otherwise do?

True enough, anytime there is a demand for an illegal commodity, any illegal commodity, there will be people who will see this as a chance to make money. Ensuring that there is something relatively harmless which is outlawed is a way of making sure that there is a reliable source of income for the dealers. It happens to be pot, it could just as easily be coffee. Rather better since it would be a much bigger market.

There's a sort of logic in that, except that it hasn't worked too well so far with pot. The evidence seems to be that, keeping it illegal ensures that the various drug markets are integrated, so that dealers will supply whatever is required, and that would presumably apply if it were coffee instead of pot which was the drug they were after in the first place, the "gateway" drug.

On the other hand, the evidence is that decriminalisation of pot, in Holland at any rate, has had the effect that people wanting harder drugs would need to find a different dealer. So rather than being a gateway drug, in this context, it can be seen as providing a kind of barrier against harder drugs.