All it would take would be a couple of EMP nucs over North America to shut us down and that includes Canada since the electrical grid in both countries is so integrated. The Chinese know this. Kinetically we could not even precisely guide our nucs against the enemy targets since we rely so much on satellites. The electrical grid would be destroyed along with all electronic communications. Anyone with an mobile phone, a laptop, ipad, home computer, tv would quickly learn how easily these gadgets can be zapped. If it were in winter your furnace would fail electronically and even if you have a backup generator, the electronic voltage regulator would also have been destroyed by the EMP. Without electricity, millions would perish from the cold. Unless you have a vehicle that has NO electronic engine management system, like 1970's and earlier vehicles with the old points and condensor under the distributor cap, your vehicle will never start again. The ability for our military to communicate with GPS, and other satelites would be crippled, making us very vulnerable to attack. Just to restore the electrical grid would take over a year, as most people don't understand or appreciate the logistics involved in restoring the grid after an EMP. Many of the giant transformers at the power stations all the way to the step down transformers that supply our homes would all have been destroyed by a THREE MILLION plus voltage induced overload to the grid by an EMP. As it is now, it is a fact that we barely have any spare transformers on hand across North America and the dirty little secret is that most large tranformers today are now manufactured and copper wound in China. The Chinese need not send any kinetics our way to harm us, all they need is low tech nucs on board a couple of aircraft that can be detonated several miles above North America and we will be completely paralysed only because our electrical grid and electronics were never HARDENED.