Legalise and regulate cannabis
The argument against cannabis is that it is getting too strong through the use of hydroponics and cross-fertilisation, and this causes problems. If this is the moral case for criminalising cannabis, then the argument collapses on the basis that all alcohol including beer should be banned on account of the fact that whisky and vodka can be manufactured by distilling alcoholic fermentations, the alcohol equivalent to hydroponics.
Cannabis should be taxed and regulated, with separate duties placed on weaker varieties of hashish and marijuana equivalent to beer duty, stronger varieties like skunk should get wine duty and the strongest varieties like cannabis oil and highly "distilled" fertilisations should get the spirit duty imposed.
Come on Ken, you want to empty the prisons, and earn a fast buck.
Why does this idea matter?
Legalising cannabis will bring millions of people back into law-abiding society, and eliminate the stigma of taking illegal drugs. If the link between cannabis and cocaine is broken – that they are both illegal drugs, it will encourage people to stop at cannabis and not experiment with other illegal drugs, which is really where the problems start.