I think that a huge blow could be made against marijuana in a simple way: legalize, even encourage the industrial production of hemp.
Female marijuana plants are grown for the drug THC found in the resins they produce to catch pollen. Thus marijuana farmers cull all the male plants, because when a female plant is fertilized, they stop producing resin.
Even so, male marijuana pollen is so pervasive right now, that better drug quality female marijuana plants have to be grown indoors to keep them away from it.
Female hemp, however, while of the same species as marijuana, produces just trace amounts of THC in its resin, but male plants still produce vast amounts of pollen.
So if hemp production is legalized, there will be such enormous amounts of hemp pollen in the air that even indoors it will get to the female marijuana plants. Thus the quality and potency of the marijuana will significantly drop.
But there is a huge bonus beyond even this, because hemp is a tremendously versatile crop, producing a very high quality paper superior to wood pulp paper, *and* also very fine fabric similar to silk.
Hemp does not need prime farmland, either, just marginal land, with minimal irrigation, fertilizer and pesticide.
All told, wide scale hemp production in the US would be worth billions of dollars every year and employ tens of thousands of workers, directly and indirectly. And instead of grinding up good trees to make wood pulp, they could be used for much more valuable lumber.
TL;DR - Reduce marijuana potency, while creating a new industry and making billions of dollars.
All good points you make here, the Constitution was written on hemp and the WW1 uniforms were crafted from hemp, we need hemp production here in Oregon to create jobs.
Yeah, Woody, that'll wreck 'em.
And meanwhile you'll be running around out there having a great time getting wrecked.