The closest parallel we have is teh Prohibition of Alcohol in the US. An Evangelically influenced Congress recognized the dangers of alcohol and it was prohibited by law (Volstead Act)to make, posses, use alcoholic beverages. This was the start of organized crime in the US and ushered in the most violent criminal era in the history of the US. Enterprising people took advantage and a huge industry developed around prohibition. Turf wars and wars with the police raged with no real victory by the police. This was the time of Al Capone and the the origins of most of the mafia crime families. A great many police and politicians were in the pockets of the Racketeers involved in the illegal sale of alcoholic beverages because the public wanted to drink and did so regardless of the law. This violent era was only stopped by the repeal of the prohibition of alcohol. It was still a very dangerous substance but the public wanted it and repealing the Volstead Act was the only way to stop the violence but only after organized crime was firmly entrenched in American society.
More recently, Mujica, out going president of Uruguay, was asked why he legalized weed, did he think smoking it was ok? He said most definitely not, smoking weed is bad, drinking alcohol is bad and smoking cigarettes is bad and no one should use any of them. He said that he legalized weed because there were 150,000 citizens that smoked it and he refused to let them be at the mercy of the cartels.