"Three or four tactical nukes set off one day (one week, etc)at a time would effectively end the US as we know it."
If they could launch one about 200 miles up of sufficient power the EMP would do it. Alas Babylon!
You said -- "If they could launch one about 200 miles up of sufficient power the EMP would do it. Alas Babylon!"
It's been reported that Iran is working on that -- for the U.S.
Regards,
Star Traveler