Hmmm..... If NK ever decided to launch against the US, I suspect that they would expect total annihilation in return. They must know this. They might be mildly insane, but, they're probably not stupid and would not advertise, to the world, what they were doing. They would have to have an "Ace" up their sleeve.
If they were intending an attack, they would be backed by other countries with similar interests. The thing about being king-of-the-mountain is that someone always wants your spot. In the world's eyes, we are the standard (or, at least, we position ourselves to be).
Russia and China are on par with us, as far as technology, capability, and resources are concerned. Tactically, it makes little sense to invade the US because it would be going to war with the entire population (thank you Second Amendment
). The only way to combat the US is through nuclear and technological attacks (from a distance).
I do not believe NK is planning to attack us. I believe they are part of a "larger picture", if anything at all is to come of this. Perhaps a diversion, drawing our attention from more, significant, threats. That's one of the purposes of a pawn. To be sacrificed. Russia and China, probably, see NK as nothing more than that.
I don't think we should invade. Let them play their hand and we focus on our defenses, in the meantime. A nuke gets launched, we intercept it over the Pacific and respond in force. I believe, if we are attacked, on a nuclear scale, no quarter should be given to the initiating country. At this point in history, knowing what we know about nuclear strikes, the initiating use of such a weapon is grounds for immediate and total neutralization of the threat.
"I own guns because the bad guys own guns. You wanna build your missile because it makes you feel safe in your country? That's fine. That's why the US has nukes. Everyone and their brother has nukes, nowadays. You shoot yours at us, though, or even whisper
the threat of nuclear attack..... we wipe you off the face of the planet and turn your country into a parking lot."
Just my $0.02,