solarz
Brigadier
Whoever thinks allowing North Korea to have nuclear weapons that can nuke Beijing in 10 minutes with little warning is in China's interests needs to think again.
North Korea is not a Chinese vassal. The only way China can get NK to relinquish nuclear weapons is to place NK under a Chinese nuclear umbrella, which wouldn't even be feasible since China doesn't have a first strike policy. Without nuclear weapons, NK would be at the mercy of US and SK, and since China has a mutual defense treaty with NK, this would be another pressure point the US could exploit.
The advantage of a nuclear NK is two-fold. First, NK secures China's northeastern flank against US, SK, and Japan. A nuclear NK is China's first strike card. In the extreme eventuality of NK nuclear attack against Japan, China can still de-escalate by sacrificing NK. Trading NK for Japan would be more detrimental to the US than to China. Second, a nuclear NK can reduce its defense expenditure on conventional military, enabling it to develop its economy. A divided Korea is not indefinitely sustainable, so there needs to be alternative options to a US-aligned SK-led reunification. One is a non-US-aligned SK-led reunification. That was the option China tried to pursue 10 years ago, but I don't think anyone still believes that to be viable. The only other alternative then is a NK-led reunification, and that is only possible with an economically strong NK.