What would China prefer to see -- a Japan armed with nuclear weapons, or Japan's alliance with the United States strengthened by its participation in missile defense? In Beijing, neither option has much appeal.
With Japan, though, China has been hoisted by its own petard. That's because a sea change in Japan's security outlook is being wrought by China's quasi-ally, North Korea. Leader Kim Jong Il is rattling his missiles and bragging that he has nuclear weapons. Not surprisingly, Japan is rapidly abandoning its longstanding delusion that its security problems can be ignored, or left to others to resolve.
No doubt, China would prefer a neutral Japan that it could dominate by virtue of size, proximity and demographic weight. Indeed, immediately after the Cold War, that outcome seemed possible. Many Japanese were inclined to think that "it's all economics now" and thus saw no danger in deferring to China as East Asia's rapidly rising economic power.