The nightmare scenario

DID the warped Machiavellians of Pyongyang miscalculate when they launched the torpedo that blew apart a South Korean warship two months ago? Proof of one of the worst breaches of the armistice that ended the Korean war 57 years ago has roiled waters far beyond the Korean peninsula. Escalating tensions have even helped rattle global financial markets. Thus far, North Korea's reckless belligerence has mostly been met with an impressive show of resolve by South Korea, Japan and America. But North Korea could yet raise the stakes again. Time for all of North Korea's neighbours to start thinking of how they might together deal with some of the unthinkables they have hitherto tried hard to ignore (see article).

South Korea has responded vigorously to the results of an international investigation that proved North Korea sank the Cheonan, killing 46 sailors. It has slapped on trade sanctions, closed its waters to North Korean ships and resumed a long abandoned propaganda blitz across the border. The measures, designed to squeeze the regime of Kim Jong Il without giving it an excuse to retaliate, demonstrate a welcome coolness and steeliness in South Korea's president, Lee Myung-bak. Shrewdly, he has mostly let the facts themselves call for censure of the Kim regime by the United Nations Security Council. He has the full support of President Barack Obama, who has stood America's military might behind South Korea.

But Mr Kim is no pushover. He has matched South Korea's moves with his own. And there is still a risk that he will follow up with more provocations. This would test South Korea's nerve, not least if there are more financial tremors that jeopardise the country's economic stability. Mr Lee needs to maintain the calm determination he has shown so far. When dealing with extortionists like those in North Korea, it is better in the long run to show strength not weakness.

It is China that has come out of the affair looking pusillanimous. Pressed by Hillary Clinton, America's secretary of state, to chastise North Korea, in public Chinese officials avoided even mentioning the attack on the Cheonan and merely called for restraint on all sides (see article). They presumably fear jeopardising the stability of their renegade ally. But that is not just feeble, it is silly. Letting Mr Kim get away with this outrage will only tempt him to try more.

What if…

If China cannot have a grown-up discussion with America about something as clear-cut as the attack on the Cheonan, how much greater will be the danger of miscommunication in the event of something hitherto unthinkable happening: an outbreak of war, say, a nuclear incident, or the collapse of the regime. Anything that sparked fears of “loose nukes” or a refugee crisis, with American and Chinese troops aiming nervously at each other across North Korean territory, could quickly make the Korean peninsula the most dangerous place on earth. China ignores such risks at its peril.

Of course neither a conflagration nor an end to the regime may be round the corner. Despite a suspected stroke in 2008, Mr Kim has tightened his political grip. His power does not appear to have been shaken even by a disastrous currency reform late last year that further impoverished hard-pressed North Koreans. He has used the Cheonan affair to stir up nationalism at home, by thundering about the threat of invasion.

But the Dear Leader is not immortal, and when he dies the succession is likely to be fraught with danger. At that point the neighbouring powers will desperately need to talk to each other through mechanisms that currently barely exist.

Each has had its own reason to look the other way. South Korea is loth to contemplate a breakdown in the north because of the cost of unification, given a disparity in living standards that is far greater than newly united Germany had to cope with. America is distracted by Afghanistan and other hotspots. China is too concerned about maintaining the figleaf of stability on its north-eastern flank to discuss the frailty of the regime. Instead all three countries, along with Japan and Russia, have focused their attention on the denuclearisation of North Korea in six-party talks which Mr Kim has used to squeeze money out of all five in exchange only for broken promises.

But the Cheonan must surely change that. For the only predictable thing about the Kim regime is its unpredictability. Planning for the other contingencies that might be in store will be difficult. Done publicly, it could encourage Mr Kim to lash out even more aggressively. But one way or another it needs to involve all five powers with a stake in North Korea's future; no one should feel left out. There are pressing practical issues, such as how to control refugee flows and whose special forces—China's or America's—might secure North Korean nuclear weapons in the event of the regime's collapse. These discussions could lead on to more sensitive ones, such as whether the peninsula should be reunified, or North Korea made into a buffer as a UN protectorate of some sort.

Before any of that can happen, China needs to recognise the dangers of doing nothing. If the Cheonan incident helps its leaders do that, the 46 sailors will not have died in vain.