what does using Mary Jane have to do with "owning" firearms?
Just because a person owns firearms doesn't also mean that they'll be using said firearms while high?
Personal responsibility has to come into play at some point.
Now if a person is high, or drunk, and uses a firearm for self protection and kills someone, they'll have a legal battle for sure.
But the 2A doesn't say anything about not being able to own firearms because you "might" par-take in drinking or smokin' weed every now and then.