an EMP would set humanity back to the stone/iron age. Many will succumb to the dramatic changes produced from no power and instantly need to re-adapt to the outdoor environment , the ecosystem would make a massive comeback, household dogs will die off or become part of feral packs that will prey on humans or each other for food
all data centers and servers would be wiped clean and all computers fried, even better- nuclear EMP's would also prevent any new circuit boards/electronics from being created. we'd lose thousands of years worth of digital information. US would probably lose 90% of its economy in less than a minute, iirc even gas powered vehicles wont be able to run due to some electronic components in automatic transmission. RF signals would be totally disrupted inside of the blast radius for years rendering radios useless, we'd need to return to using horses for travel (manual vehicles might still be functional though)
And once you run out of food its game over unless u live near farmers in the middle of nowhere. the world is nowhere prepared for a life without technology it would take up to a month to send/receive a letter even across a single state.
at that point if order is not immediately re-established by crushing military strength you could expect to see gangs and militias popping up everywhere and claiming territory, the entire foundation of america would be in ruins within a few months and it would become so out of control a foreign country would eventually invade and take over
odds are marshal law would be declared the military would be deployed to every state we'd swap from a democracy to totalitarianism, the military would patrol every county, but with no communication i cant imagine how these military groups wouldnt just go rogue