Frank Gaffney Jr. has the best analysis of the crisis brewing in North Korea in this NRO commentary. It appears the backward regime of Kim Jong Il is about to test a  missile with the ability to reach the coast of the United States. America has activated its missile defense system to an operational mode to be ready for any launch of the Taepodong-2 missile.

Gaffney explains the potential such a missile could have for the United States.
 

"This is particularly true insofar as the Taepodong 2 launch may portend Pyongyang's determination to be able to inflict the single most devastating sort of attack on this country: detonating a nuclear weapon high in space over the United States in order to unleash an electro-magnetic pulse (EMP). Such a burst of immensely powerful energy would devastate our power grid and damage, if not destroy, all unshielded electronic devices coast-to-coast.

A blue-ribbon commission tasked by Congress with assessing this threat found in 2004 that it could have a "catastrophic" effect on this 21^st Century superpower, possibly reducing it in the blink of an eye to a pre-industrial society (not unlike much of North Korea). Interestingly, the commission also established that the Soviet Union's foremost experts on this phenomenon were in North Korea. Collaborative missile testing with Iran may signal that Kim Jong-il is even farther along than we suspect in operationalizing such a capability."
 

I wrote an article based on Gaffney's research in this July 2005 WNP article.  The electromagnetic pulse bomb has the potential to reduce a modern technologically based country to a dark and vulnerable condition. That's why what North Korea is doing is so dangerous.