Nuclear Weapons – What Constitutes a Functional Deterrent?
In the early dark of the night of March 26, under cloudy skies, a North Korean submarine launched a torpedo that detonated under the South Korean Pohang class Corvette Cheonan, creating a powerful jet that broke the 1200 ton warship in half. She sunk in minutes, with 46 sailors lost. The South Korean military response was swift and firm – they suggested the sinking might have been caused by an internal explosion, or a mine left over from the Korean war of 60 years ago.
There was an investigation, eventually finding that the cause of the Cheonan’s sinking was, in fact, a North Korean torpedo, there were calls for sanctions, there were military exercises off the North Korean coast, there were bellicose statements and thinly-veiled threats. But now, the better part of half a year later, there has been no military response to this unquestionable act of war.
This allows us to at least think about the utility and effectiveness of a small, primitive nuclear weapons program as a strategic deterrent for a small or rogue nation. Now, to be sure, North Korea is an imperfect example, but we don’t have a lot of real-life cases to look at, so we need to see if anything can be learned in Northeast Asia. Obviously, something prevented the South from retaliating, even when they have many highly advanced options from air and missile strikes to submarines of their own to special operations raids against high value targets deep in the North.
Unfortunately for the sake of analysis, there are at least three layers of strategic deterrent on display in North Korea, so it’s going to remain difficult to tease out the role played by nuclear weapons. Those layers of deterrence are:
1. Nuclear Weapons
2. The conventional threat to Seoul posed by massed artillery and missiles
3. The Crazy – A fear that the North will attack Japan or do something else entirely unpredictable, with correspondingly unpredictable outcomes.
In order for a nation to actually USE a nuclear weapon, their program must have progressed to the point where it is deliverable, reliable and targetable. In the case of North Korea, their weapon is certainly not deliverable on a missile – early generation nuclear weapons are big and heavy – which leaves them with the delivery options of a suicide mission in a large cargo aircraft or overland delivery behind a massive ground attack. Both methods include a high likelihood that the weapon will be destroyed or damaged before it can be triggered. There are major questions about the reliability of the North’s weapons designs, as the tests do not seem to have produced much in the way of yield. Their targeting options are limited due to the limitations on their delivery options, so it’s reasonable to assume they would target metropolitan Seoul, without any greater concern for accuracy than that.
The North Koreans have been placing artillery, rockets and surface-to-surface missiles around Seoul for at least forty years, building increasingly hardened positions with better air defenses and increasingly deadly firepower. In return, the South Koreans, along with their US allies, have been carefully locating and mapping these positions from satellites and spy planes, deploying their own batteries of artillery and rockets with counter-battery radars and implementing any other methods they can think of to blunt the conventional threat to Seoul, a huge city of over 20 million people. It seems likely at this point that this threat could be reduced fairly quickly, but not before tens if not hundreds of thousands were killed and the city decimated.
There can be no doubt that, to whatever extent Kim Jong-il is capable of striking out in any and all directions if hostilities break out, he can be expected to do so. It’s difficult to gather any meaningful intelligence on what he might choose to do in extremis, so mostly this consideration is a matter of speculation around capabilities. What could be done with the air, naval and missile capabilities of the North, and how best to prevent their use? Most of this speculation centers on attacks on Japan due to geography, but it’s hard to know what other plans this paranoid and dangerous regime might have put in place.
In order to be effective, a strategic deterrent has to be credible. Of course, in the case of a nuclear weapon, that credibility has to be weighed against the gigantic costs if it is deployed. Certainly, the conventional threats to Seoul and to Japan are much more credible than the nuclear threat, but, at least in theory, the costs would not be as high.
So, was it nuclear deterrence that prevented South Korea from acting after the attack on the Cheonan? I think it has to be looked at in terms of thresholds. There is an action so egregious that the conventional threats have to be accepted and a military response initiated. Did the sinking of the Cheonan rise to that level? Put another way, in the absence of the nuclear threat, would South Korea have responded militarily?
I suspect not. But the challenge for Kim and the other players in the region is to determine where the line is, and to avoid crossing it. It seems that the loss of a ship and 46 sailors is hard to swallow, but nobody thought it was worth going to war over. That would have been the calculation in the North, and the bluff did not get called. This time.
AP is reporting that the North Korean navy has seized a South Korean fishing boat in the Sea of Japan and is towing it to the port of Songjin on the East Coast. One cannot help but wonder “what is the game here?”