"Last Thursday President Obama and his spokespeople sort to calm down the situation through winding back the military exercises with South Korea to lower tensions. Then came Secretary of State John Kerry’s trip to the region on Friday. The United States cannot really afford military action against Korea, it’s not in their interest. North Korea is a “good enemy” to have, and can be “managed” through upping and downing tensions on the peninsula. Korea is a good excuse to place military hardware close to China in the East Asian region.
A collapsing North would be a disaster for the US, which would result either in a united Korea where there would no longer be any excuse for a strong military presence, or there could be some conflict between China and the US to install some other form of order in the vacuum.
So (...) the Secretary Kerry’s trip to China was the result of a miscalculation by the administration in heightening the tensions on the Korean Peninsula where any further escalation could lead to irrational responses in defense. From a North perspective an attack could be seen as the best defense in these tensions.
In realizing this miscalculation John Kerry had to visit China to seek some form of “face saving” measure where the US could unilaterally de-escalate the rhetoric and action without being seen to back down." (Murray Hunter)