One interesting thing will be how prosecutors actually interpret stuff. I mean, if you're a federal prosecutor in, say, California, are you really going to want to take on the state, it's 60 million residents, and all the press to enforce laws you know yourself are dumb, and which will siphon away energy you need to pursue real criminals? Especially if, as do a lot of federal prosecutors, you might have political ambitions?
I suspect what we're seeing is the last dying gasp of the old order desperately trying to hold onto one of its shibboleths. Big Pharma hates weed because it pretty much negates the need for a whole slew of expensive prescription narcotics. Social conservatives hate it because it reminds them of hippies, blacks, young people, and everything that isn't white, patriarchal, and northern European Protestant. The GOP hates it because it can use the two things above to mobilize its base, which is super ironic because its base is busy smoking ganja out there in the boonies of those red states just as much as anyone else.