[Buckeye McFrog]

That’s because Beijing does not want to see a unified Korean state allied to the United States right up against its border: indeed, hundreds of thousands of Chinese soldiers died during the 1950-53 Korean War to prevent that happening.

The best way to secure that is to make sure that some type of sane regime takes over power in North Korea.

[Rockitz]

Move some nukes into South Korea and see if China gets serious about this destabilization of the region.

[arthurus]

A sane regime in North Korea would immediately start trying to tie itself economically into the Korean Miracle to its south. China dose not want a rational government in North Korea, even one nominally allied with China and a rational government in Norkea allied with China would be only nominally so or it would not be a rational government. A prospering and thus pro Western North Korea is as bad for Chinese sensibilities as a unified Korea formally allied with the USA.