Problem:
A lot of rural people think they can starve the cities into submission.
I hate to say this but, until we figure out how to synthesize everyone, we're kinda at their mercy.
This is always such a silly point, republicans aren't the ones growing our food, they're the ones who own the land/capital. And even if they did cut us off, every other part of the world is happy to buy services from us and sell us food.