I've suggested in the past that we should break into regions in terms of sustainable farming. What I mean is that (using your example) the Southwest US has farming blocs for the sustaining of that region and any surpluses can be traded with other regions. I don't know if that's clear nor do I know if that's reasonable, but it's a point for discussion. There's a little bit of fear in me that this scenario would be very Soviet-like. However, local and regional farming needs to be a viable option in such an economic scenario....
Just thinking through the problem (which means, if you haven't figured it out by now, it's a SWAG), it all depends upon the type of financial collapse, fast or slow.
In disaster response, a disaster that unfolds quickly is the worse kind. Government can't and usually isn't set up to respond that quickly (think Katrina, Haiti, the tsunami, Pakistani flooding), is quickly overwhelmed, public loss of confidence in the government follows shortly thereafter, and the populace adopts the opinion that "We're on our own."
That's usually when the complex, interconnected set of systems fail, one right after the other. Trade, supply, security all break down faster than the government can prop it up.
Trade fails because 1) You can't really transport the goods too far because of lack of means to do so (lack of supply), 2) It becomes too dangerous to do so (lack of security), 3) It isn't in your personal best interest to do so (you lose control once it leaves your area of influence).
Supply fails because the same way because of trade.
Security fails because 1) There's no trade, so critical stuff can't get to you (food, water, energy); 2) Loss of confidence leads to people believing they're on their own, so law and order goes out the window; 3) LEO's and the Military are quickly overwhelmed because the populace (and it doesn't take a lot - maybe about 1% of the population in any given area) feels that they have to fend for themselves, and will do so at any cost (what would you do if your wife and kids were starving?).
So, since the disaster happens quickly, government is overwhelmed, and cannot react in time to all the consequences, thus leading to loss of confidence by the populace, which leads to further failure, which leads to further loss of confidence, so on and so forth until all confidence is completely gone and any hope of a stable society is not realistic for the foreseeable future.
In contrast, a slower unfolding disaster gives the government a chance to get out ahead of the problem, and more importantly, gives the populace the impression that they are in control and addressing the problem. In many ways, whether or not the government is successful really doesn't matter at this point, what is more important is that they appear, and give the impression, that they are not overwhelmed and are actively working on the disaster. Namely, that they are competent, and that people shouldn't lose faith in the government.
So that's the scenarios and the psychology behind disasters.
