The influence can be either direct (JFK), indirect (numerous politicians stumping on fighting drugs), or the opposite (Robert Kennedy, Nixon). The drug card is a significant influence whether street level or big Pharma. Does big Pharma want the decriminalization of street drugs? Certainly not when one can take care of nausea from cancer treatments with $10 of marijuana instead of their $300/mo anti-nausea prescription drug (Zofran). We had a business in the US assisting Americans with their prescription drug purchases from Canada and I saw the bills. And don't buy into the "research and development" propaganda either, some of the recent innovative drugs have come from France (highly socialized) and the Netherlands (i.e. Spiriva).

The whole situation can be summed up by the quote from Upton Sinclair.

Most of these drugs are heinous, I'm not defending their abuse. But so long as we keep trying to wish the problem away, the mode of consumption will be abuse - because illegality leads to binging - and not to intelligent and controlled use. Just ask any seasoned police officer or fireman.

My dad is a retired fireman that spent the better part of his career in downtown Vancouver. He picked his fair share of dead junkies off the sidewalks. All the first responders working downtown hated "Welfare Wednesday" because it inevitably resulted in terminal Thursday and forensic Friday. He, and other colleagues of similar tenure advocate the decriminalization as they feel most of the real street level problems would go away.

Note I've been using "decriminalization" and not legalization. One stipulates a controlled distribution without fear of penal action, while the other denotes images of a drug frenzied free for all.

Why is drug supply prosecuted so vigorously and demand so leniently? Who in the United States is receiving drugs from Colombia, laundering the money, marketing drugs every day to 30 million U.S. citizens, bribing lawyers, the police, and politicians? There must be U.S. drug barons far more powerful than any Colombian trafficker. But the people who are dying are those fighting them in Colombia, not in the United States.

--Carlos Fuentes, A New Time for Mexico

I'd call it an alignment of self-interest. Politicians get to grandstand and act like they're protecting the children. Drug lords makes lots of money because the black market keeps prices and legitimate business competitors out.