Look for a video Perhaps on youtube called "DAY AFTER DISASTER" (History Channel) It goes through the governments protocol and response called "Unlisted" and "National Response Framework" (FEMA)
An HEMP bomb will be treated the same as an ground-burst putting US on DEFCON-1, There are only about two countries besides the US with the capabilities to explode an HEMP 250 miles above the center of the US for an wide HEMP (NEMP) affect, there are also non-nuclear EMP to called NNEMP, a NEMP are more destructive than just detonating a nuclear warhead or an in flight NNEMP as far as an EMP goes, NEMP generally cover the full radio spectrum + or what is called DC to DayLight (DCDL)
Below are two PDF: "National Response Framework" and "Nuclear/Radiological Incident Annex to the Response and Recovery Federal Interagency Operational Plans"
An HEMP bomb will be treated the same as an ground-burst putting US on DEFCON-1, There are only about two countries besides the US with the capabilities to explode an HEMP 250 miles above the center of the US for an wide HEMP (NEMP) affect, there are also non-nuclear EMP to called NNEMP, a NEMP are more destructive than just detonating a nuclear warhead or an in flight NNEMP as far as an EMP goes, NEMP generally cover the full radio spectrum + or what is called DC to DayLight (DCDL)
Below are two PDF: "National Response Framework" and "Nuclear/Radiological Incident Annex to the Response and Recovery Federal Interagency Operational Plans"