'Life-affirming' actions are the key to my new philosophy, and drugs don't fit in my scheme.
For me, drug use (and smoking, and drinking, and so on) is a kind of self-indulgence which in no way makes you a better/healthier/happier person (yes, I'm everything Thom Yorke hates, and of course I'm aware that I'm a hypocrite, not all that I do is 'life-affirming').
Personally, I'd be very happy if there were no drugs on earth.
And yet I defend legalisation, and for two reasons:
1) like you've been mentioning, it's very dangerous to put the state above the individual;
2) criminalisation won't make the problem go away; in fact, it only aggravates matters.
For example, prostitution is a scourge in all societies, and it would be better if it didn't exist. But it can
never be wiped out, it's virtually impossible, so we might as well make it tolerable for the prostitutes, who hardly ever choose the life they have. I think it's important to decriminalise it, so as to ensure decent life and work conditions, curb exploitation, stop making pimps rich, etc.
All this is in line with some of the things you've said. And also like you've said, history teaches, and indeed looking back never has prohibition of anything ever worked out for anyone.
So, I'm for legalisation of possession of all kinds of drugs. However, I also defend firm limitations to drug use, such as age restrictions and high taxation - pretty much what is being done to tobacco. Thus I find the balance between personal liberties and what you've termed 'nanny government'. This is the only respect where, as far as I can tell, our opinions diverge (legally speaking, of course), and I dare say the sole insurmountable barrier to full agreement.