world’s diplomatic relations with North Korea are difficult at best, non-existent at worst: the progress of their weapons of mass destruction programs is an extraordinary and disturbing development. But the most important regional dynamic on this issue is the interplay among South Korea, Japan, and China. China’s natural default position for several years has been to point the finger at North Korea and the United States for the nuclear weapons problem in the peninsula, and to adjust its own delicate approach only slowly and incrementally in response to North Korea’s explosive and erratic outrages. To be sure, China’s reasons are numerous, including fear of instability or conflict next door, a passionate desire to ensure there will never be a unified Korea allied to the United States, measured caution about turning its North Korean nuclear-armed neighbor into an obvious enemy of China, and fear of a refugee influx into northeast China should the nation become a failed state. Tellingly, over the last year and a half, Beijing has missed numerous opportunities to improve its relationship with Seoul and further isolate Pyongyang, by for example its knee-jerk reaction to South Korean positive consideration of deploying an American-supplied anti-ballistic missile system (Terminal High Altitude Area Defense, or THAAD) and disrespect to successive South Korean presidents. The THAAD dispute between China and South Korea appears to have been resolved in recent weeks, but the resolution included statements by South Korea that it will host no further missile-defense systems. The result has been that South Korean public opinion has turned decisively against China. However, China does pay close attention to the security policies of Japan and South Korea, not wishing to see these U.S. allies strengthen their military capacities or their security alliances with the United States itself.The end goal for the United States is clear: the stated objective (when the president is not alluding to destroying North Korea outright) is a denuclearized Korean Peninsula. From North Korea’s perspective, however, this goal faces two hurdles that Americans, who do not tend to look at things from North Korea’s perspective, do not see. Such a desire is inherently unequal, and the United States cannot be trusted.The outlook is not a pleasant one, North Korea is unlikely to give up its quest for a nuclear arsenal now. Yet domestic leaders have at various times suggested that the United States will not permit North Korea to acquire a usable nuclear arsenal. Despite all the noise, this is the first U.S. administration to have actually threatened a preemptive strike against North Korea, which if anything is an incentive for the North Koreans to preempt inasmuch as they could not assume that their deterrent force would survive a U.S. first strike. If the Trump administration continues with that line of thinking, then war is likely. On the other hand, reversing course is not contrary to the Trump administration. It’s hard to tell. The alternative would be deterrence as well as the simultaneous reassurance of allies South Korea and Japan, countries that will be more exposed to North Korean weaponry than the United States, and perhaps because of their geographic proximity, more to lose. Since this may require communicating a clear message as to exactly what North Korean behavior is to be deterred and what the allies will have to be promised, the Trump administration will have to decide what that looks like.