A reasonable part of this conversation is the possibility that an EMP could be deployed in our atmosphere that would knock out power from coast-to-coast. US government commissions have been setup to study this, and they have come back with dire predictions about how quickly society would collapse in that event. And, if you'll pardon the author's bias, someone recently wrote (http://www.washingtontimes.com/news/2012/dec/19/north-korea-...) about how North Korea's new ICBM capabilities threaten the US right now.

I'm not saying we should all be running around waving our hands in the air and acting like our hair is on fire, but if you want to talk about single points of failure, you apparently need look no further than your nearest wall outlet.