Malcolm Cook is quite right to say that Pyongyang's belligerence should not be rewarded with calls for compromise, and he's also right that shows of solidarity among South Korea and its allies are materially and symbolically useful. But should the allies try to 'increase the cost' to Pyongyang of its current belligerence?
If Malcolm is recommending economic sanctions or further political isolation, that's one thing. But if he means military replies to moves such as the 2010 sinking of the Cheonan or the bombardment of Yeonpyeong Island, then the problem the allies face is that there seems to be no viable path for the US and South Korea to escalate this crisis.
Granted, North Korea needs to know that such military actions won't be rewarded. But if the allies hang their credibility on responding to a North Korean provocation with an equal or larger countermeasure, and if that leads not to a back-down but to a further provocation from Pyongyang, then we quickly find ourselves in a cycle of escalation from which neither side feels it can disengage with their credibility or dignity intact. Rory Medcalf is right to say that neither side really wants a war, but that's not to say they are incapable of stumbling into one.
Readers with a better grasp of game theory than I possess will probably have a name for the phenomenon we are now witnessing. North Korea and its adversaries are locked in a crisis in which both sides will be much worse off if things escalate severely. Yet both sides have some interest and motivation in dissuading or deterring the other through gradual escalation, and disincentives to back down. It's really quite perverse.
Maybe a better approach to the crisis is what we might call 'studied imperturbability', in which North Korean belligerence is met with shows of solidarity, steadfastness and stoicism, but nothing which elevates Pyongyang's behaviour to much more than the status of a child's tantrum*. As Fred Kaplan writes:
...the best thing that Obama can do is what he has done—quietly demonstrate a smidgen of U.S. power, keep the South Koreans in line—and then, as much as possible, ignore the pygmy of Pyongyang. Like his father and grandfather, Kim wants the big powers to treat him as a peer. If his father and grandfather had a strange way of going about it, he has a psychotic way, and the clearest message that Obama and the rest of the world should send him is that it will not work.
* The analogy came to mind after reading Rory Medcalf's lovely image of Kim Jong Un throwing 'every toy out of the cot'. But Rory was wrong to say that Obama is the 'most morally troubled by America's possession of nuclear arms' of any US president. That description belongs to Ronald Reagan.
Photo by Flickr user zaveqna.