They are only a credible threat to south korea. Assault would be suicide, but it would be rather easy in human-wave style attacks to overwhelm some highly populated regions.
More likely, all this sabre rattling will just get them a "better deal" as most of the previous administrations have provided.
Expect more shocking news on July 4th, they plan their events around the US holidays to get more attention.
Havok-Man said:
If the Koreans nuke the USA it could turn into nuclear war hope does not UK get dragged into it.
They can;t nuke the US. Japan, soko, guam, i suppose, but not the mainland, and the spectre of global nuclear war is all but gone, so don't lose sleep.