The biggest misconception about marijuana Prohibition is that it's a pot smoker's issue, which it's not. Anyone can buy pot now and smoke it, in many places, with relatively small legal risks. Even after legalization, there are still plans for heavy taxation anyway.
Prohibition is an issue for anyone who resents paying the taxes to keep a million people behind bars at $30,000 a year. Or anyone suffering from our era's Love That Dare Not Speak Its Name, otherwise known as "mercy", who is so far out of the American mainstream that he actually feels bad about someone being in jail over something so idiotic.
Hemp is an issue for farmers. Legalizing hemp would NOT mean legalizing marijuana --- there are already low-THC and genetically engineered no-THC strains available. Even before the latest round of genetic foolery, breeding of "kif" or marijuana has been going on ever since Muhammed banned alcohol, which means that industrial hemp differs more from marijuana than a Doberman differs from a toy poodle. And if anyone has the bright idea to hide marijuana in a hemp field? Two problems. #1 is that THC is the plant's sunscreen, hence UV-opaque, so if a DEA plane flies over the field with a UV filter set the plant will stand out like Mike Tyson in a UW group photo. #2 is that dogs can (and I think do) recognize the smell of THC, and THC is a volatile chemical (otherwise you couldn't smoke it) which means that they can run through the hemp field to find your sticky stowaway as easily as they would in a cornfield. And since every plan for industrialized hemp involves registering the fields and exposing them to inspections... these are big problems.
That said, growing hemp is obviously a good thing for farmers, who used to be really good at it, and it seems better use of the land to the rest of us than paying farmers not to grow crops. You can scoff if you want at the notion of hemp paper, but even now you can buy it at specialty shops and it seems to work just fine. The only objection to industrial hemp is one of blind faith - those believing in Prohibition have the impression that thinking about the issue leads to legalization, and they insist on banning this utterly un-smokable crop for the sole purpose of preventing people from thinking about the issue.
In the end the only plausible explanation why Prohibition even exists is that it's making some people a lot of money. Unfortunately, even now the details remain extremely vague. We know that the U.S. gave five to ten thousand Nazis fake papers in Project Paperclip right after the German "defeat" ... until 1964 the Russians (who supposedly caught him) even said Hitler had gotten away. We know that there were various shadow Nazi organizations set up throughout Europe and South America to defend "freedom" by political assassinations, most famously Gladio in Italy and the Croatian group that shot the Pope, but also the Colonia Dignidad that backed Pinochet and some organization in Bolivia that I should look up again... somehow we end up in 1982 or so with the Nazi Columbian Pablo Escobar (Medellin cartel) running cocaine to be sent to Los Angeles for the new "crack" business with the CIA keeping the DEA off his back, in exchange for money that in some way or another that I forget now ended up back in the hands of the Contra paramilitaries and El Salvadoran death squads. Now I don't know what goes on with marijuana - who can tell where money goes when someone buys a little baggie? But my guess is that the brave individual entrepreneurs with grow-lights in their basements are outgunned by vast, professional operations with the political weight to control policy and the political savvy to understand that Prohibition is their friend.
To put that a little more briefly: potheads aren't the force fighting Prohibition. Potheads are the force FUNDING Prohibition.
P.S. Cogitator: you post that your 15-year-old son agreed to lie to you concerning a major drug trafficking scheme. Doesn't that mean he's guilty of conspiracy to commit the drug trafficking offense? Hmmm, time for a federal prosecutor, a trial as an adult, and a long, long prison term, no? It must be kind of fun to be a district attorney - it's like having a license to go on a school shooting spree every week.