But we can probably start out with the testimony of the Executive Director of the ACLU before Congress, Dora...
"The American Civil Liberties Union believes, and has believed for decades, that in general the best way to control the harmful effects of drugs is with a detailed set of regulations. We believe that the use of criminal prohibitions is profoundly wrong in principle, generally ineffective in practice and has created problems that the drugs themselves were powerless to create.
Criminal prohibition is profoundly wrong in principle because the state has no business using its police powers to punish adult individuals for what they decide to do with their own minds and bodies. On the most basic level, the state has no legitimate power to send me to prison for eating too much red meat or fat-laden ice cream or for drinking a few beers or glasses of wine each day. This is true in principle even if an excess of red meat and ice cream demonstrably leads to premature heart attacks and strokes. The police power of the state is legitimately used to prevent one citizen from attacking another, and to punish him if he does; it is illegitimately used to prevent adults from managing their own bodies and minds, or to punish them when they do."