China should have intervened years ago. China has a responsibility that cannot be denied, partly because of China's military support for NK during the Korean War and partly because China is the dominant neighboring country. If China can't keep the peace, then that's about the end of it.
Control your spoiled brat even if it means spanking them so hard Baby Kim is tossed from power. Otherwise, you will have sold your last gizmo in any mall in America.