After Prohibition ended in 1934 the murder rate fell again, increasing only in the late 50s as the illegal drugs trade grew. Not that drugs are not harmful. Clearly they are. Try listening to anyone after a couple of spliffs. Cocaine has the harmful social quality that it deludes people into thinking they can dance.
All drugs levy their price.
But in an imperfect world, legalisation looks like the lesser evil. It would deprive organised crime of a lush franchise, it would put a stop to much petty crime, it would reduce enforcement costs, end the problem of impure drugs and make users more accessible for treatment. The proceeds could go to educating people and treatment. Criminalisation does not work. Both of the two main parties need some lateral mind expansion on the subject.