NBC's Revolution shows us what would result from an EMP (electromagnetic pulse) strike. The government reports that if just twelve individuals in strategic locations around the United States fired rockets into the air that detonated an EMP, then it would wipe out all electronics (including all cars made after 1975) effectually sending us back to the stone age.
Doing this on just the East or West Coast would turn the nation to chaos and lawlessness. Government (Federal to local) couldn't function, Food supply would stop, banking would stop, electricity, water, sewer, all communications (Internet & TV). It would be worse if it was the whole nation. People would panic with no communication, no travel and limited to no food and water, and would do whatever it took to survive.
It would take a decades too get us back to where we were since we would have to do it all by books, with much of the recent technological information only in electronic format. And that is if we could ever get it back together before the damage of chaos and lawlessness took us to far off the edge to come back.
