I'm not an engineer by hypothetically a continuous emp pulse could disable our electrical grid?
I didn't know EMPs could restart 15 year old gas-powered generators that haven't been touched in over a decade. Or, amazingly, allow an iPod to hold its charge for 15 years and work flawlessly -- including perfect data retention -- after all that time. Or any of the other magical effects these kung fu pendants of awesome have done. (Including, incidentally, being nigh indestructable even when someone is actively trying to destroy it.)
But yeah, if EMPs (or the lack thereof) can do that even in theory, you totally nailed it.
(Incidentally, it's fairly easy to shield electronics against EMPs.)