[ClaireSolt]

It is dangerous to assert such based on assumptions. China has had this nutcase over seven times to see the benefits of liberalizing an economy. I'd say they have tried to do their part. Maybe they have about as much control over NK as Bush has over Schwartzneger sending NG troops to border.

[golfisnr1]

China gives a lot of aid to NK, especially food. They do not want a lot of NK refugees crossing the border into China causing a evacuee crisis. China cooperates in containing NK since they fear that Japan will again arm themselves. Thats the leverage we have with China.
Giving Japan antimissile capability is probably shaking up China. China's big fear is that Japan gain Nuclear capability. Japan already has the basic materials.