argument against legalization :legalization means more availability and availability leads more people to try the drug.
That is the argument against drug legalization, and as a drug user who often wonders how things would have been had I never fallen into this world, I can certainly appreciate it.
Drugs are illegal, mostly, because parents hope that their children will never happen upon this dark world, and they think that illegality will increase the chances of that never happening.
Then again, how much of this world's darkness has been conferred by the illegality itself? Not an insignificant portion. Not an insignificant portion of the world's attractiveness, either.