As I understand it, China would be able to do so easily and convincingly, since most (all?) of NK's traffic passes through China. That may even be a good theory

As I understand it, China would be able to do so easily and convincingly, since most (all?) of NK's traffic passes through China. That may even be a good theory. China might not want to directly attack US industry in this way, but might "assist" North Korea in doing so.