That is a fun novel, but it isn’t going to happen. It would take a lot more than one or two NUKES set off over the continent to effectively stop the country.
And if someone I’d shooting off nukes above our country, how long are they going to last?
It simply makes little sense or any country to try that.
If Iran or the Norks (the premise of the novel) launched one nuke from the gulf what would retaliation really matter to those affected by EMP. I doubt the EMP effect would be as devastating as portrayed in the novel but it would be, by far, the most destructive assault on the US in our history. A strategic launch of 6 spread from all three coasts would crippling. Trump signed an initiative to begin hardening vital assets but is now too busy defending himself from the enemy from within to really follow through.