North Korea has crossed the line, and there is no going back. They can't un-explode the nuclear test. They could give up the program now that they have it, but that is unlikely.
So why now? When they have refrained for so long?
Aside from the anniversaries, there are some bigger issues.
1. Relations with China were waning. Pyongyang saw China as much less interested in North Korean concerns than in Chinese concerns, and this was starting to have China act in ways that damaged North Korea - like shutting off North Korean banking relations in China.
2. South Korean FM Ban Ki Moon is about to be the UN Secretary General. It was important for North Korea, if they were going to test, to do it before Ban was confirmed, so it isn’t his fault. But Pyongyang thinks Ban will make sure the United Nations balances the United States, constrains U.S. actions and options.
3. South Korea and the United States have upcoming presidential elections; South Korea in 2007, the United States in 2008. North Korea is betting that political change upcoming in both will pressure the current regimes to resolve the crisis before they leave office. And if that doesn't work, then the incoming regimes will have to sort things out once they come to office.
4. All options are limited. The United States doesn't have the military available for a war even if it wanted to. China is desperate to keep the region stable ahead of the 2008 Olympics (all bets are off after that). Beijing and Seoul will push for dialogue, as any North Korean collapse hurts them first and more than Japan and the United States who will call for blockades. In short, there is maintenance of the status quo - a bickering among the key players - but with one key difference: Pyongyang has proven what most already knew.
So now we have a nuclear North Korea, and no good solutions.
Happy Columbus Day. North Korea's answer to "Imperialism" is … nuclear freedom?