All of which follows from a central proposition: That the leadership in the North will act in a logical and rational manner. That may or may not be true. In their deliberations they may reach a different conclusion and attack outwards first, and at that point what weapons they have at their disposal and the range of those weapons becomes very important. This also applies to Iran.
Very solid point.
There is little known about the internal power structure of NK. I can easily envision a scenario where a (dying) dictator wants to go down with a big bang. And calls upon loyal soldiers.
I just hope that in such a scenario a coup would prevent any actual strikes.
[attention, this 2 cents roll right into off-topic country]
Iran is a rather different situation though. The post revolution Iran is in a delicate situation. If they commit acts of aggression, their neighbours would seek closer ties with foreign powers to protect themselves. Which would weaken Irans posture.
Meanwhile the U.S. is not willing to do actual diplomatic efforts and does not talk to Iran. Offers from Iran has been turned down.
The U.S. is trying to keep Iran weak so that it does not become a powerfull nation assumes a leading role in the region. Instead they invade Irans neighbours, impose and continue to threaten Iran with sanctions and try to deny them their right for the civil use of nuclear energy.
In the meantime there is a very strong, peacefull and democratic civil rights movement in Iran which protest regularely against the laws imposed by the religious leaders of the country.
If played right, Iran can be the exemplary open islamic nation (from the viewpoint of the U.S.).
[/2cents]