Your post had some viable ideas and made an excellent point. But I believe the EMP must be set off at high altitude and requires a tremendous amount of energy (i.e. a nuke).
Of course, setting off a nuke at high altitude would have the most effect. But you can make conventional munitions EMP bombs. You can detonate one near a key network node and fry that node. You could do this in a city and black out a region if you know what you’re doing. It’s certainly not the same as a nuke at high altitude, but it would do plenty of damage. And the threat of having another one would be so great that the government would justify martial law to stop it.
That turns out not to be the case. Ask Saddam... oh wait, he was hung. But we did do a number on his grid.
A Doctrine for the Use of ElectroMagnetic Pulse Bombs
The Electromagnetic Bomb - a Weapon of Electrical Mass Destruction
True, conventionally powered EMP weapons are not as powerful as a nuclear high altitude burst. But since they can only affect a much smaller area, they need not be detonated at extremely high altitude either. (To some extent a nulcear EMP device must be at high altitude to get the maximum EMP effect, but a conventional one does it all on it's own).