Fiction would like to make you think the end of the US as a Nation as we all go mad max.
That's BS.
a Major EMP event that could effect a major portion of the Us could only happen by 2 ways. 1) is a man made event in the form or a Nuclear detonation in the upper atmosphere. that would likely be the end of the World as who ever launched it is about to have a full retaliatory nuclear strike coming there way.
2) would be a natural event like a Solar flare. that would knock out satellites and communications globally. in that case electronics would reset, The majority of the issues would be simply a matter of restoring the power. The Whole of the National civilian grid would be out. but you would still have preppers, hospitals, police and other agencies who have invested in preparations for disaster reacting. Some areas would have power back in days others weeks a few months for the majority of the nation back in buisness by a year powerwise. Global communications would take far longer.