How about a death penalty for using? As long as there are users there
will always be a seller...but on the other hand if all the users are locked up or dead there is no market. We have always gone at this problem from the wrong side..
Another way to fix it is to make all drugs free. Get a big building and put piles of heron, cocaine, marijuana down. Let people come in and use all they want. The drug users will all kill themselves right there...the sellers are not the problem.
No lethal dose of marijuana has been established for humans - in fact, they haven't even been able to kill lab animals larger than rats with THC.