Don't post much anymore, to busy, but have one comment to add.
Homeland Sec. had issued a large number of food and drug safety regs in the last few years. To the point where small plants like the ethanol plant I used to work for are putting in a lot of security, and larger operations like the plant I now work for have to put in a lot more. We are very open to a massive disruption of our food and pharma supplies, and it would only take a few incidents at a few key points.
We are way to centralized in our distribution networks to be safe. A few guys with rifles and some explosives could shut down food, power, and water to must major cities very quickly.