Weed don't seem so bad, haven't seen people going around robbing people at gun point while hight on weed. We still don't know if it'll fry their brain in the long run but hopefully they're dead when that happens. As for babies, yes that's a concern but stupid bishes drink while they're pregnant anyway and that seem to have more bad effects on the fetus.
As a conservative, I fully support the legalization of drugs (or at least the soft drugs such as weed). The war on drugs and the ban has only helped the drug mafias and big bankers. If the drugs are made available through government-owned shops, then the drug violence will cease, and the number of deaths from drug overdose will be a thing of the past.
Yes, what we're seeing the world over is some Prohibition Era shit... Just remind them they'll earn money from legalizing drugs, they love taxes.