I don't think that the Chinese will stand idly by and permit something like that to go unanswered.
Lets have a look at the possibilities of what could be if the DPRK uses a nuclear weapon in some offensive fashion, either against the ROK, Japan, the USA, or even a combination.
The PRC has several options.
1) (Most rational option) China cracks down on the DPRK. Hard. We're talking about the USA's Operation Shock And Awe where we hit Baghdad with everything including the kitchen sink. Basicaly, they're doing the same thing we did to Iraq because they don't want the USA reunite the North and the South by force. Instead, they want to install a socialist government that will tow their party line while playing nice with everyone else. Reparations are negotiated within the UN, and boy are they gonna be hefty.
2) China does to the USA what the USA did to the UK back when they wanted take care of that little problem with the Suez Canal. They threaten to call in our debts with them if we don't back off. (Note that this is without taking drastic measures to ensure that not only are reparations are made, but also that it doesn't happen again. In otherwords, they're tell us to STFU and live with it, which I'm pretty sure that even Russia would find to be unacceptable behavior.) This, in and of itself would have dire consequences...
-A) The USA goes "No, YOU!" and war is declared. TL;DR, bad ending, especially if nukes become involved (again). Note that this depends a lot on who we have for President and in Congress when the shit hits the fan.
-B) The USA acquiesces and loses its position as a world power. This does not, however, keep Japan, the ROK, and whatever other interested parties from kicking the holy crap out of the DPRK and China loses its only real ally in exchange for its new position of power... which, if anyone here has ever watched an elimination-by-voting-type reality TV show, can mean bad things for the country. (They have plenty of trading partners, but very few real allies.)
3) The PRC throws up their hands in despair and kindly asks that we all mind their fence. The war with the DPRK is a nasty, bloody affair with high civilian casualty rates (because, let's face it; the DPRK will put a gun in the hands of every man, woman, and child if they feel it's needed) on both sides of the border (because they're gonna want to take as many people with them into hell as possible). Even after the ROK takes control of the North they will probably be faced with a long and arduous insurgency to deal with that will probably last at least twenty years, just because the personality cult of the DPRK is that strong. Of course, I could be wrong - the USA didn't have nearly as much trouble once Japan officially surrendered at the close of World War II.
The PRC is in a very precarious position having the DPRK as a close ally. They practically installed the current government of that country thinking that, at the time, they were getting a puppet, only now they're realizing that full consequences of those actions. (The USA has suffered similar consequences with Afghanistan, IIRC, so this is not without precedence as well.) This leaves them with some very tough choices, and equally tough consequences. We have already seen Chinese ambassadors politely asking the DPRK ambassadors what the fuck they think they're doing. I have no doubt that they're doing that again right now.
Thoughts?
Lets have a look at the possibilities of what could be if the DPRK uses a nuclear weapon in some offensive fashion, either against the ROK, Japan, the USA, or even a combination.
The PRC has several options.
1) (Most rational option) China cracks down on the DPRK. Hard. We're talking about the USA's Operation Shock And Awe where we hit Baghdad with everything including the kitchen sink. Basicaly, they're doing the same thing we did to Iraq because they don't want the USA reunite the North and the South by force. Instead, they want to install a socialist government that will tow their party line while playing nice with everyone else. Reparations are negotiated within the UN, and boy are they gonna be hefty.
2) China does to the USA what the USA did to the UK back when they wanted take care of that little problem with the Suez Canal. They threaten to call in our debts with them if we don't back off. (Note that this is without taking drastic measures to ensure that not only are reparations are made, but also that it doesn't happen again. In otherwords, they're tell us to STFU and live with it, which I'm pretty sure that even Russia would find to be unacceptable behavior.) This, in and of itself would have dire consequences...
-A) The USA goes "No, YOU!" and war is declared. TL;DR, bad ending, especially if nukes become involved (again). Note that this depends a lot on who we have for President and in Congress when the shit hits the fan.
-B) The USA acquiesces and loses its position as a world power. This does not, however, keep Japan, the ROK, and whatever other interested parties from kicking the holy crap out of the DPRK and China loses its only real ally in exchange for its new position of power... which, if anyone here has ever watched an elimination-by-voting-type reality TV show, can mean bad things for the country. (They have plenty of trading partners, but very few real allies.)
3) The PRC throws up their hands in despair and kindly asks that we all mind their fence. The war with the DPRK is a nasty, bloody affair with high civilian casualty rates (because, let's face it; the DPRK will put a gun in the hands of every man, woman, and child if they feel it's needed) on both sides of the border (because they're gonna want to take as many people with them into hell as possible). Even after the ROK takes control of the North they will probably be faced with a long and arduous insurgency to deal with that will probably last at least twenty years, just because the personality cult of the DPRK is that strong. Of course, I could be wrong - the USA didn't have nearly as much trouble once Japan officially surrendered at the close of World War II.
The PRC is in a very precarious position having the DPRK as a close ally. They practically installed the current government of that country thinking that, at the time, they were getting a puppet, only now they're realizing that full consequences of those actions. (The USA has suffered similar consequences with Afghanistan, IIRC, so this is not without precedence as well.) This leaves them with some very tough choices, and equally tough consequences. We have already seen Chinese ambassadors politely asking the DPRK ambassadors what the fuck they think they're doing. I have no doubt that they're doing that again right now.
Thoughts?