Electro-Magnetic Pulse (EMP) in short, is an enemy ballistic missile that carries a nuclear weapon, launched by an enemy nation and detonated 200 miles or so above the United States. The EMP would literally fry the entire US electrical grid by throwing off incredable amounts of electro-magnetic energy (in addition to releasing thermal radiation, heat and a concussive force). Our electrical system would act as antennas sucking in a rush of electrons that would fry all circuits and burn out microchips. It is possible that the entirety of the US electrical grid would be instantly gone; rendering all our necessities of modern life that require electricity dead and useless.
Automobiles and all transportation would come to a halt, with their circuits fried. Water pumping, and sewage treatment plants would be off-line, causing untold health risks. Hospitals would be without power, meaning all of our modern medical care would be virtually non-existent.
Amazingly enough, the Department of Homeland Security does not even include an EMP attack in any of it's disaster planning scenarios.
Worse yet; the Obama administration has slashed 1.2 billion dollars from the missile-defense budget, the best weapons we have to prevent EMP attacks.
How probable is this sort of attack? This scenario is dismissed by some in the Pentagon and DHS. Does this dismissive response from our government not give a level of encouragement to any enemy that may have been considering such an attack? It wasn't so long ago that the idea that our enemies would use our airliners as missiles to attack US targets would have drawn the same response from the same officials. So, it appears that today that an EMP attack is viewed equally remote today as 9/11 would have on 9/10/01. Will the next terror strike here be an EMP attack? Is the Obama administration leaving us at risk? God only knows the answer to the former and I believe that "yes" is the answer to the latter.