It will create a black market, which probably already exists, or substitution, i.e., home-grown pot.
It already exists alright, I see it everyday in the parking lots of the 13 or so tobacco outlets and convenience stores in the 8 miles between my house and the MD/VA line. 5.5 hour straight to NYC. A $120.00 carton of Marlboros in NYC is a mere $37.00 here.
or substitution, i.e., home-grown pot.
It's easy to grow tobacco, and it's legal.