At the end of the day, it all comes down to cold hard geographical and political realities.
Unlike Syria, NK has the means and the will to hit back in retaliation at any US strike.
Any attempt by the US to target NK's nukes will present fatty Kim with a classic 'use them or loose them' delimma, and so there would be absolutely no reason for him to hold back since he will know regime change will be the next logical step after the US has neutralised all his nukes.
Even ruling out nukes, NK has enough artillery, rockets and missiles dug in along the DMZ to make Soeul little more than a smoking crater and memory if the shooting starts.
Given his past form, I would not rule out fatty K flattening Seoul as a response to an US led, Syrian-style symbolic strike, with the threat to go nuclear should the US and SK not stand down.
It is in Fatty K's best interest to go for maximum escalation in response to any attack by the US, because he knows ultimately he cannot hope to win such a fight, so his best, no, his only move, is to strike back so hard after any initial probing attack by the US, as to make Trump have second thoughts about just how much American blood he is prepared to spill to take Fatty K out.
And that is just NK on its own.
China may have massive misgivings about sending its troops to fight and die for Fatty K, but geography makes North Korea a core national security issue for Beijing. And as bad as relations have deteriorated between NK and China, I just cannot see China letting the US just destroy NK.
The very best case scenario would see Chinese troops rushing to the boarder to form a physical barrier keeping both sides apart while quietly purging Fatty K and his entire inner circle and effectively annexing NK.
The worst case scenario would be a re-run of the Korean War.
For all his bluster, Trump has no attractive military options wrt NK. If there was such an easy military option, why hasn't any of his predecessors never used them already? I mean it's not like NK has only started misbehaving in the last few months since Trump took over.
To launch any military strike against NK, you would have to except and be prepared to take massive military and civilian casualties.
Trump wants to pressure and trick China into launching a military campaign in NK to rid the world of Fatty K. Thus sustain all the military casualties of such a huge campaign, and then get saddled with the enormous bill to deal with the humiliation disaster such a conflict is sure to create, as well as the mammoth reconstruction cost of dragging NK into the 21st century.
China knows that logically there are no good military options with NK, but Trump is trying to play the 'crazy nut with bad hair' card to try and make China think he is stupid and arrogant enough to do it. Thus would be tempted to pre-empt him and go in themselves.
I trust Beijing can see through his ploy as easily as I have and hold its nerve.