For a brilliant and insightful economic analysis into the Drug War and prohibitions generally, check out this brilliant, academic treatise.
Spoiler alert: prohibition and the Drug War have caused far more harm by any measure than it ever did or was intended to help. Examples: increased potency and dangerousness of the prohibited product, corruption of law enforcement, lawyers, and judges and contempt for the law itself, cartelization of sales, the violence, and the paucity of treatment for true addicts, et. al. These all come not from the essence of the prohibited product, but from the prohibition.