I can't see boots on the ground in North Korea. They have million man army, so you'd need a huge invasion.
Plus another 5-6 million in reserve! What is more, they are Asiatics, Not Arabs. My presumption is that the Norks would pretty much fight to the death to a Man (Cultural differences and all that) so any plan for a land invasion would have to take account of that.
We also need to consider NK's claims for manufacturing a "Hydrogen Bomb". Whilst unlikely, the claimed yield of around 10Kt, whilst dismissed by most, is actually right on the money for a "Neutron Bomb" which, by its nature, has to be a fusion device with a small fission trigger.
This actually ties in well with the fact that NK's early bomb tests produced relatively low yields, again, at the time these were widely dismissed as Duds, but again, would be just what you wanted to produce triggers for fusion devices.
(Teller reckoned that making a small bomb was actually harder than making a big one)
So, even if NK hadn't launched any nuclear missile strikes, I would expect any invading forces to be Nuked as a defensive measure, either by standard or Neutron devices.
My position is that while it would be possible to overwhelm NK by killing millions of people (Think in terms of being as much as half the population, say over 10 million), it would probably not be possible to defeat them in any conventional military sense (IE Fight them to the point of surrender, at which point they come to terms)
Any attempt to invade NK would likely result in US losses not seen since WW2 unless the US had already killed millions of NK people by very heavy air attacks (And even then....!)
We currently live in an insane world where a serving soldier can gfo to prison for putting a dying insurgent out of his misery. Do we really have the stomach to kill 10 million Norks (Including indiscriminate collateral slaughter of millions of civilians) and suffer heavy additional casualties ourselves and in the neighboring countries to boot? I doubt it somehow.
(Even if defeated, Seoul would certainly be destroyed and NK might even send a missile or two to Japan before their facilities are destroyed)
True, but the old adage of 'an army marches on it's stomach' is still true today and I can't see how the Norks can keep that massive army fed, watered and supplied.
They have been preparing for this for 60 years, I dare say there is quite a lot of food and fuel squirreled away in very deep bunkers scattered all over the country.