Or just spread the word that jury nullification is a civil right. It only takes 1/12 jurors to hang a jury. That's 8% of the population. If it's done consistently, and prosecutors realize that there's a good chance of a hung jury every time they bring a non-violent drug crime to trial, they'll start not bothering. If 10-15% of the public nullify, they'd have to try every non-violent drug crime multiple times on average to win a conviction. If defendants start realizing that they're difficult to convict, they'll start opting for a jury rather than a plea.

Hit the swine where it hurts: their pocketbooks. Right now, the "war on drugs" is a profit center. Remove the ability to profit and its reason for being ceases to exist.