North Korea

U. S. intelligence says North Korea could have a nuclear-tipped ICBM capable of hitting the U. S. within six months or less.

The media tends to set the threat in terms of losing an American city, but a more fundamental threat would be exploding a thermonuclear device in space that would create an electromagnetic pulse to take down the U. S. power grid.  The question is whether North Korea has a device powerful enough to pull that off.