Legalize it and tax the hell out of it like booze and cigs. Regulate it so consumers actually know what the hell it is they are smoking (i.e. this type has 2% THC). Make it a legitimate and legal enterprise. Take marijuana supply chain management out of the hands of bad people.
The regs should be the same as booze i.e. can't toke and drive, can't smoke a J walking down Douglas St., must be 19+, etc.
Booze labels tell us the dosages. 5% or 80 proof or whatever so actual adults can get a sense whether they will enjoy a nice buzz or the hammer. Makes sense, no reason it can't be done for herbs.