Stan and I recently had a comment exchange about where the third flank of war would arise. I said it would be somewhere unexpected. When I said that, I meant here rather than Iran. Little did I realise that it might be North Korea.
Whether or not you believe whether the detonation was successful (reports conflict), it sends a message to the international community that we are in trouble. The North Koreans already have ICBMs and you have to wonder how long it will take to attach a nuclear warhead on to them...a matter of years.
The UN, being the useless pile of bureaucrats that they are, are helpless. Financial sanctions on a country that doesn't give a flying proverbial about its people are about as useful as Mary Whitehouse's dishcloth.
Thankfully even China have come around to seeing the evil in their communist ally's folly. To disguise the development of nuclear technology under the pretence that it is to deter the "evil" US foe is, quite frankly, ridiculous. The US may have some dodgy foreign policy but having lived there for the better part of ten years, I can assure you that every person means well and wants the rest of the world to enjoy the freedoms (and in some cases hell) that they do. You make your own luck there, and reap the dividends.
Anyway, I digress. If Kim Jong-Il thinks he's proved a point, he's probably right. As someone famous once said "let China sleep, for when she wakes, the world will be sorry". Right quote. Wrong country.