Many ways that would cost China and NK much more than the US. That's how you play the game, make it hurt more for your opponents than yourself. Right now, even the possibility that NK could flip to the US makes China treat NK with baby gloves, and as a result they have a nuclear capable country right on their border. You think China's leaders are happy about that? It's another potential hotspot they have to worry about that could spill into China in addition to all the other hotspots they have to deal with thanks to the fact that China borders more countries than any other in the world. More stress on the Chinese government = more ways they can screw up. +1 for America.
The "kid" in the phrase "kid gloves" doesn't refer to children. It refers instead to leather made from kid goats. Kidskin leather is thinner and softer than other kinds of leather, and doesn't leave smudges on delicate articles. Hence the phrase "kid glove treatment", implying handling something with delicacy and tact.