Drugs: Legal or Illegal?

Laws against the use of various drugs are typically justified in two ways: preventing harm to the person who would use drugs, and preventing harm to the broader society (because a society is harmed if a lot of the people in it are harmed). Arguments for decriminalizing, or even legalizing, the use of various drugs involve claims that people are free to make their own decisions and live their own lives, even if they harm themselves; and claims that in practice laws prohibiting drug use tend to increase harm to individuals (for instance, by incarcerating non-violent offenders) and to societies (for instance, by turning the sale of drugs into a lucrative and violent criminal enterprise). What, on balance, is the best policy—in terms of well-being and in terms of rights—about the legal status of a range of different drugs?