I can't really be bothered writing an essay length reply to this but I do feel like voicing my general opinion.
As far as alcohol and smoking goes, I have no issue with either being legal. Alcohol is generally pretty fine for you as long as you know your personal limits and aren't stupid about having it. Smoking may be bad for you, but in this day and age everyone is educated to at least the basic issues with it, if they want to smoke and destroy their lungs and such, let them. Although as smoking can also be harmful to others, I like the way the Australian government is going about banning it in various public places like train stations (in the underground ones where the air is stagnant, it is awful to be near a smoker).
As for illicit drugs like cannabis, ecstacy, speed, etc. I believe that they should remain banned, overall they have worse side effects immediately and generally there is no "safe" ammount. Some may argue that with some people that it is fine, it gives them a bit of a high but they are still in control however, with most people this does not appear to be the case. Others may argue that it goes with smoking, most people are aware of what they do and it should be their choice, I don't believe this to be the case, illicit drugs have much worse shortterm effects and if you do get "peer pressured" into trying them then it can turn out significantly worse with alot less consumption (ok, you don't really consume cigarettes, but you know what I mean).





