[Obama's] strategy [is] based on the idea that if the United States shows it is willing to greatly shrink the size of its atomic arsenal, ban nuclear testing and cut off the worldwide production of bomb material, reluctant allies and partners around the world will be more likely to rewrite nuclear treaties and enforce sanctions against North Korea and Iran.And that strategy might not seem quite as silly if there were any indication whatsoever that it could ever work. Sanctions are meaningless unless they're unanimous (sort of like test ban or emissions treaties), and of course they never are.
There is nothing that can be done to punish N. Korea while China's support continues unwavered. The U.N. is meaningless, and can't even muster a slap on the wrist, having no ability to slap. When has scolding a dictator from afar ever worked?