First, the Interstates to the cities will be cut off. Trucks entering or transiting will stop. Immediate panic will set in and rioting will begin as all shops and stores are looted.
There wll be no money. ATM’s will cease functioning as banks horde their physical $$$.
In the cities, chaos will prevail
Meanwhile, outside the cities, weapons will be oiled and readied
Yup. Cut off all supplies to major cities. Within a few weeks, the urban ferals will be too busy hunting pigeons and rats to fight.