Could China Weigh In Now?

Fred Kaplan wonders about North Korea's nuclear test:

Chinese have no desire to see North Korea develop an effective nuclear arsenal. Like the Soviet Union during Cold War days, China doesn't want subordinate powers to acquire independent means to make mischief. China also fears that a nuclear-armed North Korea might compel Japan to go nuclear, which would pose a threat to China in the long run. When North Korea set off its first nuclear test, the Chinese were clearly frustrated but didn't extend their harsh words to action. It's conceivable that this second test, especially in the wake of the missile testboth of which violated Security Council resolutions that China endorsedcould alter Chinese calculations. In the past, the Chinese have put their narrow national interests above the interests of regional security and nuclear nonproliferation. Maybe this latest move will tip the scale in the opposite direction.