If I can add something from my own national and cultural perspective - on the issue of prohibition of drugs in general. And I can only comment on what I know from my own jurisdiction - these are general comments, not trying to tell anyone what their policies should be (except my own government that they're fair game for me).
Prohibition has boosted both organised and casual crime to levels that, thirty years ago, I would have scoffed at. Remember this is my country I'm referring to, not anyone else's. We didn't think through the issues and we developed our policy approach in a reflexive and not reflective fashion. We criminalised drugs which many years earlier were not criminalised. Cocaine was available from pharmacists - it was a required ingredient in many proprietary medicines. I won't go on about how drugs were criminalised, let's just say they were.
If we wanted to hurt organised crime - and to a lesser extent casual street crime - then we would decriminalise and regulate drugs. The market would force prices down as legal corporations began to produce high quality (ie without dangerous additives) drugs sold in a regulated market. The morons making big money out of clan labs would go bust overnight. Here it's easy to grown cannabis, you plant it, water it and wait. You don't have to be a horticulturalist to produce plenty of it. Demand and supply should see the price of cannabis plunge and it would cease to provide seed capital (sorry for the awful puns) for bigger operations.
And as far as personal harm goes. Yes, drugs are a big issue as has been pointed out in the thread. But any drug, by definition, has an affect on our physiology, both acute and chronic. But if we know how to use it safely (eduation) then go for it. As far as public safety goes, no quarter given. You drive a motor vehicle on a road affected by any drug at all which affects your ability to drive safely then your driving days are finished. Same for other behaviours. No excuses. The excessive use of liquor or drugs has in fact in our criminal law been a defence (!) to some charges. A druggie who stabbed an off-duty cop had his charges reduced on appeal to our High Court because he told the court his ability to intend to harm the cop was impaired by the use of drugs (O'Connor, 1980). You use any drug and someone gets hurt, no excuses.