Even such a “limited” EMP impact would be devastating. Consider the consequences of even just, say, NYC or SF or Seattle being completely shut down indefinitely - that’s, say, 10 million people with no transportation & limited supplies, all major internet data traffic thru there shut down, extensive power grid damage, etc. National resources would be devoted to recovering & re-routing around the problems. Maybe not TEOTWAKI, but that doesn’t make it trivial.
The problem with comparing 1960s era consequences is electronics of the time were relatively very robust (and still suffered lots of problems from EMP). Wouldn’t take much to destroy all the electronics you rely on daily now.
“Even such a ‘limited’ EMP impact would be devastating.”
I agree. But in this context you have to define what you mean by “devastating.” There’s some hype studies out there that talk about 90% of the US population being killed, which is utterly ridiculous.
Maybe an EMP over the northeast would fry most computers in a 700-1000 km area. That’s not proven, but maybe that would occur. Still, that would leave buildings, roads, bridges, etc intact, and the world would not doubt rush in a lot of replacement computers to protect the US economy.