Outlawing drugs in general is a very modern invention, and it seems to have made things worse rather than better. Our jails are full of people who have committed victimless crimes. There are others in jail for crimes committed only to get the money needed to pay exhorbitant prices for drugs, while these prices are elevated far beyond the real cost of the goods, only because the goods are outlawed. The extra money goes to some of the worst elements of society. And of course society pays for all the crime that is necessitated only by the artificially elevated price for the drugs that people choose to buy.
Now there are risks to society associated with drug use. We don't want people getting stoned and causing automobile accidents. We don't want people neglecting their families to buy and use drugs. We don't want potentially productive people wasting their lives. Yet these are exactly the behaviors we face from alchohol use, and we manage to deal with them.
Let's be even-handed. Legalize drugs, but don't legalize irresponsible behaviors of the type caused by alchohol as well. Regulate the quality of drugs sold just as we do other consumables, to eliminate the risk of contamination. And get the prices down to lower the crime rate, reserve prisons for those who harm other people, and cut off the income of the drug lords.