Good question. I guess the first questions could be:
Do we focus on the demand side,the supply side, or both, and do we treat them the same way?
Do we try to regulate the drug trade gradually out of existence or do we try to criminalize it out of existence?
I don't know the answer for sure, but am willing to give it a shot in the dark:
Learn from countries that have a proven success rate in bringing the drug trade down. China comes to mind. After the opium trade imposed by the British so as to try to balance Britain's trade deficit with China, some estimate that the male addicted population was about 25%. It's probably a high estimate, but it does reveal that however high it was, it had clearly reached epidemic proportions. The fact that the British had won both Opium Wars over Chinese attempts at regulating opium, thus allowing the British to impose the trade of opium without restriction ensured that the epidemic could reach proportions no country would normally tolerate. A country that can find means of fighting such an epidemic effectively once it had regained national control over its own laws is certainly a country that would know a hell of a lot more than we would about how to deal with the drug trade effectively.
The Chinese had learnt their lesson well. You deal with it at the supply side. Anyone caught selling illegal drugs in China is sure to get the death penalty or, at the judge's discretion, life imprisonment. And they do not care one iota if you're a Chinese citizen or a foreigner. They will protect their population from such evil.
Are we prepared to learn from those who have real experience in this and who have in fact succeeded in bringing a trade of epidemic proportions under control?
Let's consider too that China's liberalization of the opium trade was not of its own choosing, but was imposed by military force. Are we prepared to be so stupid as to liberalize drugs on our own soil freely and willingly as China had done under foreign military force?
We've seen the epidemic that liberalization can cause by China's example. Are we prepared to submit to such an epidemic freely and willingly?
Let's learn from history and those who have the knowledge and experience.
Criminalize the sale of illegal drugs, with the death sentence or life imprisonment being applied as selling such drugs essentially amounts to slow murder
China doesn't deal with the addicts except as medical cases. It goes after the supply side, not the demand side, but it cracks down hard on the supply side. They have plenty of historical experience in such matters. Let's learn from the best in this matter.
The British had imposed what you're proposing on China, and it led to an epidemic. Are you sure you want to revisit that? Ask the Chinese, and I'm sure they'd think you're crazy. Their drug trade is more or less under control today, but over a century ago, it was rampant owing to British-imposed liberalization. Is that really the route you want to take? What makes you think things would be so much different in Canada than was the case in China? Are we somehow special and immune from such epidemics? Why would liberalization succeed in Canada where it had failed in China a century before?
Deal with the supply side and cut off tis head... literally if necessary.