Well I would still doubt EMP in any event is the huge national crisis some make it out to be, and I read about Starfish. The results still didnt show the potential to render large parts of the nation powerless and without cars or electricity unless you were using an especially powerful EMP-and Iran’s military budget is not near high enough for that. You do need to have a very high military budget in order to be a national threat to large nations. Of course, this could still be a matter of life and agonizing death for Israelis.
Powerful EMP is a function merely of the gamma rays emitted by the weapon, and not TNT-equivalent yield.
Further, much more of our society is based on electronics than back then: and those electronics are more sensitive to EMP.
Shielding against lightning-induced surges is not sufficient either, as the characteristic waveform(s) of the EMP effect are very different.
As far as the technology -- Starfish Prime detonated at around 240 miles height. Some of the links I sent you show that the EMP pulse for a device detonated over the Northeast US would be much worse than Starfish Prime. And Iran has already launched a satellite into orbit at 160 miles height, and is planning to launch one to orbit at 22,000 miles.
Technology is no longer a barrier.
And you cannot go around pre-emptively taking out satellites; but waiting until the EMP hits is *too late*.
Cheers!