No one here remembers TEMPEST then?
Fibre optics and faraday cages. Job done. That's the TEMPEST programme in a nutshell. Nominally about eavesdropping prevention, but also extremely convenient for EMP resistance. Three decades or so ago,so it needs to be reinvented round about now.
Or, alternatively, use valves (vacuum tubes) not semiconductors. Like everyone was astounded to find in that Russian fighter whose name I forget.
More PR for the US military pork barrel.
"I have no idea what WW3 will be fought with, but I'm sure WW4 will be fought with stones."
WW3 is in progress at the moment, the dollar is the weapon, and the Chinese are winning.