Nah, Revelation is pretty clear about the proportion of the population that is killed on the earth. Remember though, we are to pray that our tribulation does not start (with the announcement in the Temple that “IT” is a god) in the winter or on a Sabbath which will tell us it is THE Great Tribulation. Otherwise, localized.
There really hasn’t been any other time that the world has been so small and controllable by the few. An EMP would delay the Great Tribulation. Satan gets to rule the whole world and show his hate of humans. Anyway, I digress.
I don’t think Biblical prophecy (OT or NT) has anything to do with the United States, except insofar as there are Christians and Jews in the United States.