It took a "constitutional amendment" to make alcohol illegal in the USA. Why not the same for unapproved "drugs"?
The whole "drug war" is an employment machine for cops, prosecutors, court and prison officials--nothing more.
It is curious to note that the anti-drug ads that the alcohol industry conveniently put out omit all the problems that their own "product" causes. . . while lumping cannabis with other (illegal) drugs.
The pharmaceutical industry also has an issue with cannabis . . . how does one patent a plant?