Kim Jong-Il has done it. A nuke test less than 2 hours ago. How does this change the situtation? What’s next; sanctions, blockade, war? What will China do? What’ll the US do? Will this effect Ban Ki-moon of South Korea being elected as UN Secretary-General?
More carrot and stick. Maybe China will pull us out of the mess with renewed six party talks. 
Well, assuming it’s verified, I think the important question the OP didn’t ask is what will Japan do. I have no clue.
Well the South Korean stock market took a plunge. China had a 20 minute warning which they shared with us.
AFAIK, Japan has the capability to respond quickly:
http://www.fas.org/nuke/guide/japan/nuke/
Mmm…
Maybe I have to take back a prediction I made a long time ago, I thought the first city to go up in nuclear smoke in the 21st century was going to be in the Middle East. It seems the Far East does not want to be left behind. 
I would be cautious as to whether an actual nuclear yield has been produced until some sort of confirmation, through seismic or other means, has been obtained.
With that said, there’s certainly going to be a lot of saber-rattling over the next few days, by both sides, but the situation remains much as it has: stalemate. NK still does not have realistic chance of taking over the South. The acquisition of special weapons by NK, if true, makes it considerably less likely that they would be invaded by anyone, but the question is, despite its institutional paranoia, was an invasion of NK ever that likely to begin with?
I could foresee Japan possibly going into a crash program to develop special weapons of their own (no cite, but I seem to recall numerous stories that Japan has nuclear material and has the technology to assemble fission weapons fairly quickly if they wish to). On preview, I see GIGObuster has cited that information.
Options by the US are limited, and have been ever since it committed large percentages of its military to Afghanistan and Iraq. My guess, and only that, is that NK would be reminded by some discreet means that a nuclear attack on Seoul, or worse yet Japan, would result in retaliation in kind by the US. I would be very surprised indeed of this had not been made clear long ago.
And now I’ll step aside and let the real experts weigh in.
One thing it means is they’ve run out of escalation room. Up til now every time they’ve wanted more attention they’ve upped the nuclear lever one more notch. Now there’s nowhere for that lever to go but out and out nuclear war, which I’m certain even they are not deranged enough to do.
What they will do next time they feel ignored, I cannot imagine.
China, however … I’ve long thought that the only real resolution to the NK situation was for their patron state to lose patience with their prodigal son completely and invade.
Actually I suspect a full-on invasion wouldn’t be necessary, a demonstration on the border and an order to Kim Jong-il to stand down or else would be enough.
If Kim ever gets cancer…
yeah, hes a crazy shit. I think if he sees his future going down the tubes, he’s going to bring everyone he can with him
North Korea lacks the capability to project a nuclear weapon at the entity it says provoked the test–that is, the United States. In light of this, the test seems tactically irrelevant, although symbolically important, I suppose. Japan probably need not seek its own nuclear program, as a nuclear launch from North Korea would almost certainly trigger a retaliatory response from the States, but from a geopolitical standpoint, it might make sense for them to do so.
I’d really like to see some kind of psychological profile on Kim Jong-Il. I feel his move here was not irrational–just extremely antagonistic. He fears an invasion, and not entirely, IMO, without reason. As long as Jong-Il can convince the American administration that he’s somewhat unstable, and as long as he can reasonably claim that he has active nuclear weapons, he probably need not fear direct American military action against his homeland in his lifetime. As it stands, I don’t see him as a psychopath per se, just a cruel dictator with a desire for self-preservation. Which is so much better.
What will be interesting is his response to economic sanctions, which is a tactic that might be employed at this point. Would he interpret them as an act of war? Or will he deal with it, perhaps risking some sort of popular rebellion (assuming sanctions greatly decreased the quality of life in North Korea).
Now I want to play DEFCON. Anybody pick that up yet?
I should clarify–psychopaths don’t necessarily act irrationally either, they simply lack empathy and manipulate others. Therefore, it may be accurate to call Jong-Il a psychopath, even if he is somewhat rational. A missile launch from Jong-Il’s deathbed, for no other reason than to go out in a nuclear blaze of glory, might be psychopathic behavior, but I’m not yet convinced it’s something he’d do.
I’m beginning to realize that it’s tough to define “rational behavior” at the level of state actors.
Well, South Korea’s equivalent of the USGS is reporting a tremor… but I don’t know.
I’m wondering if it was maybe a really big conventional explosion.
Someone here brought up the possibility that he just waited for the next natural earth tremor and claimed it as a nuke. That would explain the odd time of day. But if so I’m sure the seismic signature will tell all.
So the USGS has confirmed that something happened. But if Kim Jong-il really was waiting for a natural occurence to use as a bluff for a nuclear test, how was he able to give China 20 minutes warning before it happened? Are they easy to predict? If they are, wouldn’t his bluff have been called by now?
South-Korea’s minister of foreign affairs are espected to be elected as new secretary general of UN today. Perhaps have NK’s action have something to do with this?
Whatever has actually happened, I don’t think the “odd time of day” requires any particular explanation. The United States has detonated a number of nuclear weapons at 36 or 37 minutes after the hour (see Chetco, Muskegon, Truckee, Harlem, and Pamlico from the Operation Dominic series back in the '60’s). Even assuming North Korea would likely schedule a test for the hour or half-hour, a minor spot of technical difficulties could cause a six or thirty-six minute delay.
Lots of people have attempted to perfect earthquake prediction, with no particular degree of success.
The New York Times and Washington Post say that the USGS detected a 4.2 tremor, which is stronger than the South Korean report. Everybody seems to agree it was a man-made explosion, not some coincidence - the one question is whether it could be some other kind of bomb. More results will come later this morning.
The GoP has to be loving this development. The Foley thing will lose the headlines, and they get to play the fear card again…
Another potential wrinkle–Iran can argue they’ve been treated more harshly than NK, which apparrently now has nuclear weapons…