Just looking back to 1941 it was sanctions that drove Japan to launch a First Strike against Pearl Harbour.
I doubt that there is a NK embassy in the US but it doesn't mean Kim hasn't smuggled in an atomic bomb.
More likely, US will strike first, and then the US deep state will explode a dirty bomb in a major city, and blame it on Korea. That will tighten the screws toward a martial law state.
Kim knows the neither the US, S, Korea, or China want to invade his country. The best possible solution is for NK to give up its atomic program and be able to feed itself again. That is why Trump putting China on the line might work. And if it works, all MSM praise will go to Xi.