I've said many times before in here that I'm a firm believer in the harm principle - that is, that the government has no business curbing your behavior so long as your actions don't harm others.
Except that the word "harm" can be either narrowly or broadly defined to suit one's own political beliefs. Just one example - alcohol is perfectly legal to consume if you're over 21. And there's no prohibition or limitation on said consumption even if you're married and have young children. Are you going to suggest that a father who is drunk all the time, even if he's not physically abusive, is not causing some amount of harm to his spouse and to his children with his behavior?
How about cheating on your spouse? Does that cause harm to your spouse?
Seatbelts are another example, as are motorcycle helmets. The argument against rules requiring those things is that if you die in an accident, you're only harming yourself. Is that really true though? Does your death cause harm to others, such as your family and friends?
I could go on, and on, and on. It isn't as simple "I'll ingest whatever I want because I'm only hurting myself, so leave me the hell alone." Maybe if you're a hermit with no friends or family that might be true. But that's not true of most people.
So where I come down on this is, if a solid majority of society deems something to be detrimental to society as a whole, then the government has a role. But even then, it needs to be done with a balancing test of your rights as an individual and whether those outweigh the rights of society as a whole. I wold argue that your right to be drunk or high in public doesn't necessarily outweigh the right of society to interact with a sober public. Recent attitudes towards drugs have shifted drastically, and that is concerning to me.