I think the ones to watch are the SOUTH Koreans on this.
They would be the first to suffer if Little Kimmy got frisky. Most of the North’s missiles are short range and can’t reach the U.S., plus we’d place anti-missile defenses just off his coast to blunt his threat.
The South has (arguably) the better military and I’m sure they have every square inch of the North marked off on a map. Plus they’ve been on the receiving end of Nork crap for generations. The U.S. would not want to cross the 38th Parallel but if the South went across first ... well ... can’t let our allies hang in the wind, can we?
And if Little Kimmy threw a nuke, just one, even the Chinese would be hard pressed to justify his continued survival.
Nothing NORK does is without Chinese knowledge and approval. China could put a stop to ‘Lil Kim at any time. That he is allowed to continue his bullshit just means that China is okay with it.