On the surface the antagonists are NK and the US. Dig a little deeper and it becomes apparent North Korea is a proxy in a much larger struggle between the US and China. Like a pit bull on a leash, Kim can be reined in or given his head in a balancing act orchestrated by Xi. 

It allows China to enjoy the best of all worlds. It can reap the rewards of a lopsided trade relationship with the West while matching American hegemony with its own in Southeast Asia. Its long term strategy, of course, is to displace the US as the region's policeman. The ineptness of the Trump administration is accelerating that process. 

With hawks and doves perched on either of Trump's shoulders, no doubt he's getting sharply contrasting advice. While all options might be on the table, the smart money is on tougher economic sanctions. And yet, with an unstable, unpopular Trump and an unstable Kim, military engagement can't be excluded.