Not simply shutting off power and communications to a civilian area as we seen in Ukraine and Gaza. I’m talking the fictional trope where a country when it wants to invade and takeover another country using EMPs (either nuclear blasts near space above the target, or dedicated EMP weaponry) to basically destroy any and all resistance before their occupation. The Red Dawn remake has this happen, where the North Korean/Russians launched an emp missile the night before the invasion of the United States West Coast so any local resistance (police, national guard) would be isolated and cut-off and allowed them to immediately take over various towns and cities immediately.
My thought is, wouldn’t that literally be scorch-earthing the very areas you intend on taking over before you get there? No organized resistance is nice, but now your attempts at pacifying the local populations now mean you now need to use your own resources and logistics to keep them alive otherwise they’d all turn on you. Simply blowing up a power/communications hub, then repairing it once you’re actually in charge seems far easier to do.
If you want to be able to move your tanks through the streets it’s a lousy idea. Very few vehicles these days would survive an EMP blast. Every car on the road just became your self-imposed blockade. You’d spend your first week just trying to make it to the center of town.
For nuclear EMP there is no really good modeling on where and how severe the effects will be. You really don’t know the shape of the footprint nor the intensity contours. I have to assume the major nuclear powers have some modeling tools they use, but given the worldwide testing history they’ve got to be based on very little actual experential data. Which suggests confidence in their outputs ought to be low, and ought to be regard as low by the decisionmakers.
Nuclear EMP weapons will have effect footprints of hundreds or thousands of miles. Non-nuclear EMP weapons will have effect footprints of a couple hundred yards or so. There are no tools in the middle ranges.
I’d ask first why the desire to “invade and take over”. History has shown that owning dirt, wrecked infrastructure, and a hungry restive population stopped being beneficial maybe 150-200 years ago. Basically post the Industrial Revolution.
If you want to cause regime change, perhaps because the enemy regime is threatening you, do decapitating strikes. If you want to disable a totalitarian, target all his (always “his” for some reason) secret police and domestic intel apparatus then await the internal chaos in his country to finish the process. If you want to prevent or stall an invasion, target the military C3 nodes.
If you’re just a nihilist and want to inflict maximum pain on the enemy populace and government, and build up your credentials as a wild-eyed psychopath who’ll stop at nothing, why not permit the same EMP-causing nukes to hit the ground instead?