In order for the sanction on North Korea to be effective, international cooperation is essential, and China needs to take a more active role in making the UN security council resolution effective. Even if the US and the international community imposes sanctions on North Korea, without China, all the efforts would be futile. China has great influence in North Korea. Therefore, China should no longer advocate North Korea, and face the reality. North Korea is no longer an ally to China. North Korea is a menace that will harm China's well-being. North Korea's nuclear development is not only a threat to the US and South Korea. It is a threat to East Asia and the world. If the Chinese government wishes to protect her people, and maintain peace and stability, nonproliferation in North Korea should be China's number one priority.