I agree that it is not a democratic state that they fear but one that doesn't interfere. I don't think China considers North Korea a threat though. It is a de facto ally even if the North Korean government pretends it has never had nor needed help from China.
China doesn't consider North Korea a direct threat to China. They
do consider it one of the greatest threats to stability in the region, including the threat of a nuclear war that, if it happened, would inevitably have a massively negative impact on China.
I think they also provide necessary fuel supplies and food (which other countries not aligned to North Korea do too: Japan and the US for a start).
Actually, they've taken on numerous humanitarian roles. Motivations for that are mixed. Part of it is a result of pressure from the international community. Part of it is to try to prevent the influx of illegal immigrants from North Korea. And part of it, who knows, could actually be out of legitimate concern for the conditions of the North Korean people.
I don't see how a revolution or war would be in the interests of stability. Even at the best of times that is a massive gamble and the history of such things don't suggest that stability quickly follows. A destablizing war or revolution is probably one of the last things they want. I think the possibility of a lot of refugess is a big one in that case.
Please note that I didn't say a war
would result in greater stability; only that China would welcome greater stability, and if a war/revolution brought that about, they wouldn't be opposed to it. However, from China's perspective (for example), a military coup that overthrew the current leadership, and replaced it with a more rational one (ie. one that didn't threaten nuclear war, and provided better for the people of the country) would be a very good thing.
You see to suffer under the impression that China is blind to how bat-**** crazy the leadership of North Korea is, or how much of a threat it represents to the rest of Asia (and potentially other parts of the world). North Korea is, in fact, one of their biggest foreign policy focuses, and
most of their energy is focuses on "let's keep these crazy ****ers from starting a nuclear war". If you check out recent political meetings between China and North Korea, you'll see that they consist of nothing more than a very thin veneer of 'friendship'; but under that is a very great deal of distrust and paranoia (on both sides).
I wouldn't like to bet on the outcome of a war between North and South Korea and I wouldn't bet on a "minimal support role" for the US. Why do you suppose these two things?
North Korea's only two significant advantages are its nukes, and its massive standing army. The U.S. role would be to shoot down any nuclear attacks (a role with which China would not have any major objections); and the standing army is largely powerless in the face of South Korea's significantly more advanced army. It wouldn't be an overnight victory...but with American warships shooting down North Korean planes and missiles, South Korea would win.
However, as I stated, I consider this to be a much
less likely scenario (at least in the near future) than I do a military coup from the inside.
I think if Kim Jong-Eun rides out the initial doubts and he can portray himself as some military leader and heir to his father and grandfather then he won't be easily deposed. Why would anyone with the power to depose him do so given that they have so much more to lose if they can't rally support from the general ruling population?
"Rides out the initial doubts"? There are very few 'doubts' from the common people, they've been trained and conditioned to accept whatever the propaganda machine tells them. It doesn't matter how he "portrays" himself...nor does he really have any control over it. It is the vast military/political machine that controls how he's perceived. So long as he's useful to them as a figurehead, they'll build him up. But if he were
ever to show signs of independence, that same propaganda machine could destroy him. He simply
does not have the power, control, or experience that his father or grandfather did; he's a puppet for others who are taking advantage of this situation for their own benefit.
Yeah, the day could come -- a decade or more later -- when he enjoyed enough power, and had the experience to use it, to wrest control for himself...but quite frankly, I'd predict that he'll be dead before he reaches that point. Either killed and replaced by another figurehead, or more likely removed in a military coup.