Earlier quoted context omitted.
Laying it all on Nixon does not explain "Reefer Madness" (1936) nor every other country that criminalizes drugs with zeal.
Nor does it explain the original Prohibition, a single paragraph of law that created an explosion of organized crime, reclassified a tremendous percentage of American adults as lawbreakers, and filled prisons. Prohibition is a timeless, recurring issue. I think it comes from something even more timeless: moral authoritarianism. The urge felt by many people to force their neighbor to do things the Right Way. The purit…
This is an innate aspect of society. See: murder, sexual assault, etc. Morality is a human construct.
The real question is where to draw the line, and the answer isn't immediately clear, even in a court of law.
I do agree with you though that moral conservatism needs to move on from the 1950s.