@Brent cv,
It is possible that China could entertain thoughts of curtailing North Korea because the more radical N. Korea becomes , the more they threaten China as well . Never underestimate the folly of a terroristic dictator . Kim Jong Il could hit China with missiles as easily as he could hit Japan .
My thoughts are that N. Korea will expend their full arsenal of missiles in test firings soon and then have no sword to rattle .