I think if the Chicoms were to decide that they wanted to take over North Korea we should let them. As bad as the Chicoms are they at least have a semblance of rationality and we can talk directly with them. Kim Jong mentally Ill is one of the most serious threats the world has ever seen and we should step aside if Hu decides to take him out.
The PRC knows all of this and will use the N. Koreans, and IMHO,
is using the N. Koreans, to agitate, test, and measure our (and the West's) repsonses so that the ChiComms themselves can increase their power and influence in the region. I firmly believe that they do the same with the Islamofascists in Iran and Pakistan to the extent that they can. IMHO, that is more of what this is all about than anything else.
All warfare is deception - Sun Tsu