Way back in 1996 two things happened. First, The state of California passed proposition 215 becoming the first state in the Union to legalize medical Cannabis, and equally as important, the writers of the Simpsons were coming up with ideas for season 8, which was still very much in the golden age of the Simpsons.
One of the episodes they wrote was the classic episode "The Canine Mutiny". The plot revolves around Bart getting a credit card, which he crazily uses to buy everything he can out of a magazine. Yes, people used to buy things with credit cards, over the phone, out of magazines. It was a simpler time. One of the things he buys is Laddie. Laddie is supposed to be the world's greatest dog. Of course, eventually when they come to repossess everything that Bart bought, they have to give a dog back and instead of giving Laddie, they give Santa's little helper. Bart, of course, realizes that this is a terrible mistake and has to track down Santa's Little Helper. who ends up having been adopted by a blind man, Mr. Mitchell, who has made Santa's Little Helper his best friend. Through a series of Simpson's hi-jinks the super dog Laddie has ended up working for the police. In what should be a sweet final scene, Santa's Little Helper decides to go home with Bart, while Laddie starts sniffing around Mr. Mitchell lovingly.
Of course, you are watching the Simpsons and so Laddie instead discovers Weed on Mr. Mitchell. Chief Wiggum is about to arrest them when Eddie points out, "Hold on Chief, it could be medicinal Marijuana". To which Mr. Mitchell adds in, "Yeah medicinal Pot, without it I could go even blinder! Right?" Then Chief Wiggum decides this could take a while and calls into help which includes most likely prostitutes because again...Simpsons.
Of course, when the episode was written and aired only one state in the Union had medicinal Marijuana. California.
Could this put the debate to rest? No, of course not. However, it's as good a theory as any and this debate has been raging for all 30 seasons of the show. Yes that's right. The show has been going for 30 years. It could run for Senate at this point.
Check out the original episode to examine the evidence yourself.
Simpsons World | The Canine Mutiny | season 8 episode 20
Bart gives away Santa's Little Helper so he can keep a fully trained, blue ribbon Collie.