Our whole society?
Do you really think that the only thing keeping most people from frying their brains on drugs is the threat of arrest?
I don't even drink alcohol anymore, and it didn't take corrupt jackbooted police threatening my freedom to make me stop, just a good serious talk with my doctors about some compelling test results.
Here's the thing - our society is already eaten through with rampant addiction. Addiction to alcohol, tobacco, and any number of other dangerous drugs. Drunk driving is involved in some 40,000 traffic deaths a year - nearly half of them - and tens of thousands more acute and long-term poisonings. Effects of tobacco addition kill nearly half a million people in the US each year. And high school students surveyed reported that it's much easier to get illegal drugs than alcohol or tobacco.
So I really don't see why you think that things would be so much worse if we dismantled the police- and prison-state and the enormous profits that accrue to violent criminals from trying to eliminate certain kinds of drugs.
Sure, we'd still have addicts, drunks, and people with smelly clothes, but we wouldn't have police kicking down doors in the middle of the night or drug gang turf wars, and I think that's a fair trade.
Unfortunately that's about the only option left for those interested in preserving their society - and all it accomplishes is to postpone the downfall for a short time, at the expense of liberty lost in the process.
As you say, at the expense of liberty.
Also, the surrender of liberty itself atrophies the moral muscles needed for self restraint.