"Marihuana's relative potential for harm to the vast majority of individual users and its actual impact on society does not justify a social policy designed to seek out and firmly punish those who use it. This judgment is based on prevalent use patterns, on behavior exhibited by the vast majority of users and on our interpretations of existing medical and scientific data. This position also is consistent with the estimate by law enforcement personnel that the elimination of use is unattainable."
Shafer, Raymond P., et al, Marihuana: A Signal of Misunderstanding, Ch. V, Washington DC: National Commission on Marihuana and Drug Abuse, 1972.