What I dread is that if it becomes legal, parents who are users will be much more casual with their stash and the kids will be able to get it for free, not for $$ from some Son of Barack.
You don't know frustration until you try teaching pot smoky smelling kids with bloodshot eyes and shit-eatin grins on their faces who given even less than a crap than when they aren't stoned. One advantage is that they are too wasted to cause as much trouble.
Imagine how it will be after a few generations.
No one ever looks at the section of the world that has been using Cannabis and Hashish for a couple of thousand years, while Europe refused to adopt it as an intoxicant, but did use beer and wine, and alcohol.
One culture became vibrant, and healthy, the others became like the universal pothead that we all know.