I do think that
people have a right to harm themselves. If you want to go in your house and
smoke 50 packs a day and
kill yourself,
be my guest. But just don't do it near me.
Your right to swing your fist ends where my face begins. I agree. But if we are sitting inside somewhere, and you start smoking, you are violating my rights. I already have asthma, and I really have no desire to add lung cancer to that.
Saige is right, in that this isn't a question of your right to hurt yourself, but of your right to cause direct harm to others. And since studies have shown that second hand smoke is dangerous, when you smoke near me it is infringing on my rights.
Now, the more sticky question is whether the government should be allowed to regulate smoking on private property. IOW, if I own a restaurant, shouldn't I be able to decide whether or not people can smoke in my building? But, to be honest, I really don't care for economic liberties that much, and I say that the health concerns outweigh whatever rights you have to conduct your business without interference.