[justin66]

> 2. The US begins importing most of its food from elsewhere.

I'd argue that the more plausible outcome is what economists predict: US agricultural interests would have to compete and domestic prices for food would go down, while the price that struggling economies which export food can charge for that food would go up. Competition... and the various parties involved focusing on what they're good at producing.

On the other hand, we in the US do tend to be pretty idiotic about largely abandoning business sectors when the going gets rough.