This is totally unrealistic for all sorts of reasons but than one being that setting off a bomb at exactly the right size of explosion and point in the atmosphere to create an EMP pulse over the maximum area while having no detonating on the ground is actually extremely difficult.
Could you hide as a mistake a single blast that went off over the NE US and had an EMP impact on Boston or NY doubtful but maybe, could you justify as accident the multiple simultaneous strikes to hit CONUS, forget it.
There does seem to be a strain of thought in the US that wants to create a fantasy like Red Dawn, where the US becomes the good guy insurgents against some big bad overlord power, whether it is invasion by aliens or zombies or just as in a recent TV show electrical power just so how doesn’t work anywhere.
It is presumably a reaction to try and ‘play soldiers’ but the US is so how uncomfortable playing the conquering occupying power a la Iraq which is closer to reality, so wants to refight major power conflict but that means a nuclear war with millions dead and the war over in a few days, so there is no heroic story, so ‘somehow’ can we have major war but just not use nuclear weapons.
It obviously is also in the interests of the arms manufacturers of the things that are not needed to fight ISIS but would be used in a ref ought long term ground war with Russia.