Many U.S. policymakers see China as the answer to North Korean proliferation. If Beijing would just tell the North's Kim Jong-un to behave, East Asia's biggest problem would disappear.

Of course, it's not that simple. To be sure, the People's Republic of China has influence in Pyongyang, but the latter always has jealously guarding its independence. Kim is no more likely than his father to let reason get in the way of his rule.