A key policy question concerning drugs is whether it should be legal to produce and use a drug. The answer can vary by drug. In the United States, anyone can legally consume the caffeine in soda or chocolate, but no one can legally consume heroin. Alcohol and cigarettes can be consumed legally by adults but not by children. Drugs such as Ritalin and Valium are legal only with a prescription. Cocaine cannot legally be used as a recreational drug, but it can be used as a medicine. (It is useful for certain types of eye and nose surgery.)

The drug legalization debate concerns whether the legal status of one or more drugs should be changed. It would be possible for some- one to argue that a substance that is now legal should be prohibited, or made illegal. In...