Car Wars Reloaded

[yoodle]

My idea isn't much different than the others mentioned here, but maybe a little simpler...

Terrorists successfully set off nukes in a number of U.S. cities, completely destroying them (NYC and DC would be obvious choices). Fear and paranoia turn other major cities into fortress towns. Newcomers are not welcome, and vigilantes begin executions of suspected terrorists. The economy quickly spirals into a the greatest depression ever seen.

The suburbs and rural areas quickly fall into chaos as gangs of unemployed and desperate people gather together to take what they can from those who still have it. Many attempt to go to the big cities for protection, but are turned away. Few farms are able to defend themselves against the increasingly well armed gangs, and food production gradually decreases over time.