Re: Mixed lessons from history?
"The Chinese aren't going to militariliy intervene in North Korea"
I hope you're right. Unfortunately history provides many lessons where parties who have little skin in the game today, and parties who don't particularly want to fight each other, get sucked into conflict on opposing sides tomorrow. Contrary to earlier comments, the North have been making troop movements. The International Institute for Strategic studies points out that thought their army is technologically stunted, they have the fifth ranked army in the world and stand a good chance of being able to overrun Seoul before being stopped. As someone noted above, instability within a country's borders easily translates into the aggressive promulgation of war outside it's borders. The paranoiacs have severed the god damn hotline to the sane external world. Now a small skirmish could all too easily start the domino effect and the result could easily end up with the US and China sucked into the worst kind of situation without wanting to be there in the first place.
Hypothetical - but this is one possible path to illustrate how it could go wrong.
1. North Korea shells South Korea, as they are wont to do and have done several times before.
2. The South have ignored outrages in the past, but have also been very close to retaliating. The North go a little too far. It only takes one image of a fresh faced child bombed to pieces to force a governments hand. The South retaliate with a surgical strike.
3. The North get a bloody nose, and fat Kim, his fresh young face all red, comes under pressure from the old guard and feels he has to give a show of greater strength. He knows they stand a good chance of being able to take Seoul (using the "secret" tunnels they have dug into South Korea - the South knows they have these but doesn't know where they all are), and is starting to feel he is between a rock and a hard place if he is not to be deposed and end up some generals f**k puppet. He issues instruction to for a rapid storming of Seoul, calculating a comprehensive win will give him all the home brownie points he needs and he calculates, he might be able to get a ceasefire in exchange for a deal on Seoul. Even that foreign body, the International Institute for Strategic Studies points out they have a good chance of success, and his own generals are saying it's near 100%.
Multiple possible further scenarios a and b now have the domino dynamic.
4.a. The South are rightly particularly paranoid about scenario 3. They know geographically they are at a strategic disadvantage and facing one of the world's largest armies. Also, though the North may be technologically falling behind, they are well trained and motivated. Additionally the South are aware the North doesn't really have to move troops into position for such a strike, because they have always been there threatening to strike since the last Korean war. Either because they determine 3. is about to happen OR because they think for whatever reason there is a good chance 3 is about to happen, they launch a pre-emptive conventional forces excursion into the North, with the intention of incapacitating the North's own "quick strike" capability.
4.b. The South plan 4.a and move troops into a defensive position but initiate air-strikes to pre-emptively degrade the North's capacity for a fast strike. Because airstrikes alone won't stop a well dug in army, they need heavy gear only the US can provide.
So with either scenario 4.a or 4.b there is a high chance the US will provide Stealth Bombers for such air strikes. The US after all have promised to stand security guarantor to the South.
5. The North are now fully paranoid and ready for action. They are sweating in their bunkers as the reality bites and they know there are nuclear capable Stealth Bombers flying over god knows which parts of their country and that they might be above them at any given moment. There is no dialogue with the outside parties (the idiots severed the hotline remember). They have no sense of proportion, no way of knowing if the conflict is a limited air campaign designed to stymie their capacity to invade, or something more. Those damned stealth bombers could be anywhere. Kim is really feeling the heat - not knowing at any moment if the US are about to use tactical nuclear weapons or other means to attempt to disable his ace card, his nuclear arsenal. Under pressure he goes for broke, and hits the big red button marked Seoul. Now even Apple would be unhappy at how they are about to gain the advantage over Samsung.
6. The bomb has hit. This is where no matter how friendly or advanced or intelligent the various parties involved are, the playbook has gone out the window and "strike first to ensure survival" takes over. Perhaps the US hits all areas of North Korea with tactical nuclear weapons in an attempt to prevent an even worse nightmare, perhaps the nukes they use aren't of the tactical variety. Whatever, they know they have to strike hard and fast as Japan or even possibly Hawaii are at risk if they don't. Who can say what the playbook is now or what China would do. China itself, though it will have plans, may not even know what it would do come such an eventuality. One day they are worrying about harrying Apple on consumer TV programs and producing cheap Android phones, the next they are in a situation where there is nuclear war on their doorstep with the US, South Korea and Japan a united force attacking a strategically important country on their doorstep they have previously declared a military Ally.