Casualties from the Iraq war just keep on coming. About 4,300 American dead, God knows how many Iraqis, and now a big one in east Asia: the Korean war armistice, which has held for almost 56 years, but yesterday was unilaterally repudiated by North Korea.

The connection is fairly obvious, although it still escapes most of the media. Iraq had no weapons of mass destruction; it got invaded. Iran may or may not have plans to build some; it gets threatened with military action. North Korea tested a nuclear bomb three years ago; it gets a mixture of bribes and angry rhetoric. Conclusion: deterrence works.

So let’s review some basics about deterrence, since most people seem to have forgotten the lessons of the Cold War (or never learned them in the first place). First, nuclear proliferation has a good record at keeping the peace. The Americans and Soviets, armed to the teeth, still kept their hands off each other for four decades. India and Pakistan fought three wars in the 30 years before India got the bomb, but only a skirmish since.

Second, publicity is central to deterrence. If you’re developing a weapon to use in a surprise attack on your enemies (or surreptitiously on-sell it to terrorists), you’d be crazy to advertise the fact. But if your purpose is to deter, then you want everyone to know about it. Kim Jong-Il’s openness about his nukes supports rather than detracts from his claim that their purpose is defensive.

Third, a reputation for madness helps deterrence along. If you’re not sure about your nuclear-armed adversary’s sanity, you’ll be less likely to take them on, and also more likely to offer generous bribes to induce disarmament.

None of this means nuclear proliferation is a good thing. One day, through accident or miscalculation, the deterrent may fail to deter, and then disaster looms. But in the short term it’s more likely to reduce the risk of war than to increase it.

With this in mind, we can try to get beyond the last couple of days’ rhetoric over North Korea. Kim is most definitely eccentric, but there’s no evidence that he’s behaving irrationally. His nuclear program is an entirely rational response to the incentives he faces; if we want him to give it up, we’re going to have to change those incentives.

Gareth Evans (remember him?), in the course of a generally sensible piece in this morning’s Age, remarks parenthetically that “nobody seriously believes [North Korea] would be suicidal enough to” initiate a nuclear attack.

In the circles Evans moves in, that might be true. But the popular media have been doing everything to create the opposite impression: that Kim represents an immediate and possibly catastrophic threat to his neighbors.

It’s not true, and the rhetoric of fear is just making things worse.

It’s time for everyone to take a step back and calm down.