There’s really nothing wrong with existing U.S. drug policy, except that all but one of its underlying ideas is false.
The one true idea is that drug use can be a dangerous activity for drug-takers and others, both because people under the spell of intoxication partially lose control of their behavior and because people under the spell of addiction partially lose control of their drug-taking. It follows that a purely free-market approach to addictive intoxicants will not lead to good results; taxes and regulations are necessary, and prohibition may be justified. Whether prohibition is actually justified for any given drug depends on the risks of the drug, how deeply socially embedded its use has become, and the state’s capacity to enforce it. (In my view, the answer is “no” for alcohol, but “yes” for cocaine.)
But this simple truth is taken, by both U.S. domestic law and policy and by the international drug control regime, as implying a number of stark falsehoods:
That the addictive intoxicants we have chosen to prohibit are radically different in nature from alcohol, the addictive intoxicant we have chosen to permit;
That all use of the illicit drugs is “abuse,” pathological in origin and result, causing harm to users and others.
That all, or at least most, users of illicit drugs are addicts, or on their way to addiction.
That, because drug-dealers are often violent, and because users often engage in acquisitive crime (since prohibition has made drugs artificially expensive), in addition to intoxicated crime, it follows that enforcing the drug laws naturally tends to reduce non-drug crime. The opposite is more often the case; greater enforcement (unless specifically targeted at the most violent dealers) tends to create incentives for more violence, because violence is one way that drug dealers protect themselves from enforcement.