Outsider:  Duh....of course NK knows an attack on the US would spell doom.  That's not their goal.  Their goal is to achieve full membership in the nuclear weapons "club" with the belief that it would enhance their ability to interact with other nations.. Certainly having a nuclear arsenal and the ability to deliver it as far as the US would deter any efforts to invade NK or to support any efforts to overthrow the regime.  The real question involved, not discouraging an attack of the US, but somehow keeping NK from have that full potential....and the time is running very, very short.  Gary Crum