Well, let's look at the real threat. It is that Japan now has an excuse, and will face popular demands, for a resurgent military. That will truly send shudders throughout East and Southeast Asia, even two generations after the second world war. But how big a threat is that?

In the long run, it is inevitable that Japan's military presence will be proportionate to its gigantic economic size. The region should get used to that; it's only a matter of time. The more the world reacts to Pyongyang, the more Tokyo has an excuse to speed things up. The region's interest lies in the slowest possible Japanese resurgence.

In the long run, threats are, after all, governed by economics. You can't fight wars you can't afford, even if you can precipitate them. And there's the rub. Most of the world doesn't want North Korea to precipitate a war. The North would, in the end, lose, but we don't want the horrible consequences for South Korea of a lopsided opening battle: Seoul is close to the demarcation line; Pyongyang far distant. And China doesn't want 5 million refugees on its border - from a new Korean war. The bottom line is this: a war that Kim Jong-il starts will be the end of him, and he knows it.

So, what does Pyongyang want? Steve Bosworth, once the US ambassador in Seoul, says it wants to be noticed, taken into account. Given the idiosyncrasy of its leadership, and as long as that leadership continues its high-wire art of survival, all this is to be expected. And the world is giving Mr Kim just what he hoped for - centre diplomatic stage.

Are there new elements in the equation, aside from the so-called nuclear threat? There are. China doesn't want Pyongyang to carry out nuclear tests, and Washington and Seoul know that. Therefore, it can be counted on to work with both leaderships, as well as the UN, to co-ordinate a measured reaction.

The way to deal with the 'threat', therefore, is not to ignore it. But, the world must also avoid giving Pyongyang what it wants: satisfaction and a reaction. Right now, Mr Kim is getting precisely what he wanted: world headlines and ego satisfaction. Given the intelligence that the surrounding powers had on the imminence of a nuclear test, there could have been a co-ordinated response: a muted and negative, but downplayed, reaction, which would have devastated Mr Kim. In other words, he hadn't made it into the big boys' club, after all.

So let the fun begin. Chinese sanctions that bite and are clearly aimed at regime survival, should be instituted quietly, giving Mr Kim no public-relations excuse to start military movements. And if he does attempt any provocative moves, they should be countered: first, with enhanced sanctions - not on food, but on technology and energy.

And second, with US naval movements. Mr Kim would get the message: further nuclear tests and becoming nuclear ready would mean his own destruction, not from a nuclear strike, but from a thousand bites. He can do simple arithmetic; he understands that he is utterly dependent on China's goodwill, which he has, in large measure, sacrificed.

The objective now should be to 'get help from the enemy'. Let Mr Kim be hoisted by his own petard, let his provocation be an excuse for the quiet moves that will destroy him in a few years. Patience in this case will work, because the regime has no friends, no 'rear base', and no long-term basis of survival. Let's see how well he can tough it out among his own comrades if the world seems to be paying him no attention.

Scott Thompson is a professor at the Fletcher School of Law and Diplomacy in Massachusetts