Nicotine is a mood altering substance. I smoke cigarettes, and if I don't have one, I'm grumpy. It is also mind altering, as in it alters your brain chemistry. Actually, I should say it's brain altering. Mind altering like Marijuana? no. Worse than Marijuana? definitely. Why should I not be able to consume Cannabis if I can legally increase the risk of myself getting cancer greatly? Cannabis puts you in an altered state of mind, but at least it's not nearly as harmful as tobacco/nicotine. Why shouldn't an 18 year old be able to drink a beer too? It's silly. All laws against controlled substances are bullshit, really. I am not condoning the use of crack, and meth, etc, but the laws really do nothing. If someone wants something, they will get it... regardless of age. But if Cannabis were legalized, 18 or 19 would definitely be a fair age. At 18 one is legally an adult. Why should 18 year olds not be treated like adults too? 18 year olds are just as liable for committing a crime as a 21 year old, so why should the age be 21? An 18 year old could go to prison for 5 years, just as a 21 year old could be. Do you see what I am saying? As maturity goes, 21 is not a big step. I think 18 and 21 year olds, in general, would treat it the same. I've seen crazy parties involving 21 year olds, so what makes them so much more responsible with mind tering substances? Really, though... 18 is the legal adult age in the US.

17 is a bit too young, because 17 year olds are still in high school usually, and that could condone the use of it while in high school. That would be pretty sad if someone legally went to high school stoned every day, and didn't learn a damn thing.