News yesterday of North Korea's attack has sharply raised fears regionally and worldwide that the peninsula may be on the edge of a full-blown military exchange. For once the hyperbole does not seem unjustified.
So what explains the actions of the North? The official line from Pyongyang is that the South fired first. Although the evidence for this is questionable, Monday saw the start of a series of routine military manoeuvres which the North has claimed represents preparations for a full-scale attack.
To most dispassionate observers this seems like propagandistic misrepresentation, although it is a good example of the sense of vulnerability and isolation that is typical of the North Korean leadership.
More plausibly, at a time when the North has been grappling with weak economic conditions, food shortages brought about by flooding and the uncertainty surrounding the succession process for the young heir Kim Jong-un, the government may be looking to a foreign crisis as a means of shoring up support at home. Conflict abroad can mobilise domestic opinion, reinforcing the position of the military and legitimising a leadership in transition.
Equally relevant, Pyongyang may have calculated that, in anticipation of a re-start of the Six Party Talks to address the North's nuclear weapons programme, tough action on the ground might translate into a stronger position at the negotiating table.
What can be done to move the parties back from the brink of a mutually devastating conflict? A calibrated military response from the South and its allies is overly risky and threatens loss of civilian and military life on a huge scale, as well as massive economic dislocation – the ripple effects of which would be felt throughout the region and the world. Sanctions have been tried many times before and always fail. This leaves diplomacy as the only creditable option – and a long-term process of engagement between the international community and North Korea.
In all of this, clarity of language and unity of purpose will be key. Above all, the national leaders involved should keep in mind the stakes. They are two countries with a combined population of about 70 million which are heavily armed and in such close proximity that military action would be catastrophic.
The author is a senior lecturer in international relations at the University of Cambridge