Let us place the threshold at "requiring public assistance." It is my personal opinion that any father who is allowing someone else to pay for his kids should not be enjoying himself, whether it be from drugs or any other cause.
Want to toke or play video games all day? Pay for your kids!
If some private business man makes a good salary, owns a home, pays his/her taxes, etc, but wants to get stoned in their backyard around a campfire every weekend - its on them.
And this is eminently less objectionable. You eliminate injury to others (dependents or taxpayers) and you've begin to have a reasonable argument in favor of letting people play with drugs, though i'm not sure whether or not the conditions will remain stable long term.
Im a father of 3 boys age 9,8 and 3. I never smoked pot. Not once. Yeah, drank some beer in High School, went to keg parties in College, etc. I knew plenty of people who smoked pot, most turned out fine. But no, I dont want my sons to touch pot. I will always vote against legalization.
Pot doesn't destroy everybody. Neither does alcohol. But it does destroy some. The question is, what sort of losses should we regard as acceptable?
I'm all for that ... now how do we enforce it: banning video games and pot? Or something more narrowly tailored?