There is a tool toward a solution. Our economic relationship with China. If China was told that was on the table, North Korea's nuke program would be dead. That relationship, in terms of economic benefit is oneway, in China's favor, because as far as cheap foreign production for U.S. and European companies go, there is no lack of people or willing partners all over Asia.
But, we are dealing with a forty-year myth that the economic changes in China will produce Chinese "moderation", in the political and human rights realms, in spite of twenty-plus years of evidence that demonstrate not a single instance of either one.
We are dealing with self-deception about China - delivered and turned into a mantra from our State Department - that is as insidiuous and self-serving as the self-deception they had for forty years about the origins of Islamic terrorism.
We are dealing with free trade treaties and obligations.
China has strategic interests in holding down NK, too, but it also doesn't want to be swamped with refugees. Anyway this is far off the topic of this thread.