I'm curious what you think would happen if KP nukes a city or two in the US. I presume we'd nuke them back, but then what? How does the rest of the world react? How would SK and China, in particular react? Surely this is a known plan?
That said, I could easily see them shooting ballistic missiles into the ocean 100 miles off the west coast at random times to cause disruption and chaos in the state that provides the biggest chunk of the US GDP (California).
The FAA and US would have no choice but to react as if it "might" be heading for landfall and unable to "launch on warn" because of the geopolitical consequences of obliterating a chunk of KP when their "harmless test" did no damage at all, would be high.
So in the "perception is everything" game, KP's moves appear to me to been about making themselves look good and the US look bad.
So my non-foreign policy analyst position is that this where I see this going over the next 5 - 10 yrs.
I have no idea what Russia will do in this scenario. Anything seems possible.
And of course during the chaos Russia takes Ukraine, NATO curses and gnashes teeth but the US has KW2 on its hands and does nothing.