The EMP would not be the killer, in either case. Oh, maybe a few, but the real bloodbath would come when the lights stayed off, whe no one could find out why and for how long.
At present, we have a situation where the population is primed to riot and fight, between the class warfare angle to the racial one. Put that in urban environs with a rapidly shrinking food supply, and major cities will be trashed within a week or two.
Recall, the opening shots in Serbia were graphite filament bombs (BLU-114/B) aimed at taking down the power grid.
Our angle during the Cold War was to take out the population and military of any aggressor. We even developed a bomb designed to preserve infrastructure and eliminate people, not the other way around.
However, we have become increasingly dependent on electronic devices, from waking up, to keeping time, to inventory, shipping (barcodes/readers) from rail cars to envelopes, and in the virtual regulation of processes from HVAC to electrical generation. Points of exposure exceed anything the Y2K problem could have impacted, because even 'dumb' devices would be affected in a cascade of failures--IF the systems are vulnerable.
For a third-worlder, it would mean they would have only to deliver two or three effective devices to bring down the US, a major coup for a third world wannabe strongman.
Better to have them pursue this than a bioweapon (which just might get the job done and could be far tougher to interdict of control.
Hopefully, your assessment of the actual vulnerabilities is on target, and our enemies are chasing a worthless goal.
You bring up a more important situation than EMP will ever be: Our weakness of simple attacks.
A coordinated attack on our electrical lines, sub stations, and other electrical delivery systems could have significant impacts. We, of course, would recover within a few weeks but is a window of opportunity for an enemy to do other damages.
That said, I don’t want to be the Soviet Union, afraid of everything and locking down everything; passes to go to the town next door, a pass to buy gas, a pass to so much as fart.