Why Nuclear Deterrence Doesn’t Matter that Much in Korea

Last week we had a good speaker at PNU on US extended deterrence in Korea. Much of the discussion focused on nuclear weapons. NK has them obviously, and speculation on NK capabilities is endless. So not surprisingly, SKs are increasingly thinking that they should have them too. While it seems straight-forward to say the North has them, therefore the South should have them too, I think this is inaccurate– and not because America doesn’t want SK to have nukes. Koreans bristle at this, as many states in the world do, because they feel that the Non-Proliferation Treaty (NPT) constitutes nuclear discrimination: the haves (including the US) get to keep their nukes while the have-nots stay de-nuclear on the vague promise that the haves will build down to zero. Needless to say, the NPT haves have done little on this, leading to regular cries of hypocrisy (although Obama seems to genuinely want ‘global zero’). So last decade, India openly decried this logic and went nuclear despite the nuclear haves’ resistance.

But nuclear weapons for SK would not actually serve SK security much regarding NK, because any nuclear use by NK on SK would immediately trigger a SK invasion of the North. It is hard to imagine SK absorbing a nuclear strike without this finally forcing Seoul’s hand to invade NK and end the long stalemate. A nuclear strike would be so devastating that no other possible retaliation – airstikes, port-mining, more sanctions, etc – would be countenanced. An invasion is practically a 100% probability in response to a NK first-strike on the south. While the initial reason for the retaliation would be to suppress NK nuclear capabilities and force regime change, in reality it would quickly to turn into a war of national unification – a second Korean war to finally close the rift. Every analyst I’ve ever heard or read thinks that SK would win such a war – even without US, Japanese, or UN help. It would be a harder slog alone of course, but it is still quite likely.

So, after the SK victory, SK would then be stuck rebuilding NK, including cleaning-up blast zones in the NK from the US or South’s own nuclear strikes. As such, SK is unlikely to ever launch in the first place. There is no point in creating mass devastation one must fix a short time later. More formally stated, a SK second-strike is irrelevant, because a NK first-strike would change SK’s preferences toward from defense and deterrence to irredentism. A NK first-strike would end SK hesitation and confusion on NK and push it openly toward intra-Korean ‘imperialism,’ i.e., irredentism and unity.

Note the difference between N and SK, and the US and USSR. Neither the US nor the USSR had any compunction about nuking each other’s homeland, because neither expected to bear the clean-up costs. The same might be argued for the Indo-Pakistani nuclear competition today. But Korea is different. SK would not nuke NK in response to a first-strike and then just walk away. A NK first-strike – given the special ‘divided nation’ status of the peninsula – would push SK into the long-awaited, much-speculated-upon Second Korean War. And this time there would be a pretty clear winner who would then have to pay for all the reconstruction. So it would be better to have, say, 5 blast-zones in the south, than another 5 in the north too.

The only possible alternative I can see to this is SK nuclear use on the North if SK was actually losing the unification war. If NK launched a first-strike that devastated multiple SK cities and threw the military into disarray, then SK might consider a ‘counter-force’ nuclear strike on the NK People’s Army in order to slow them down and buy the Southern military time to re-organize and win the war. NATO considered similar such counter-force strikes during the Cold War. If the Red Army was rolling through Western Europe on the way to victory, NATO reserved the right to ‘first-use’ against military assets to stem the Soviet tide. But even these strikes would be very limited in Korea – likely low-yield battlefield nuclear weapons. The idea of nuking NK cities – ‘counter-value’ city-busting – is likely off the table due to the massive reconstruction costs that Seoul would have to carry for such strikes a short time later.

Beyond that SK nuclear weapons might be construed against China, Russia, and Japan – the first two of whom are nuclear. De Gaulle famously said French nukes pointed ‘360 degrees.’ And the initial aim of the French nuclear program was as much Germany as the Soviet Union. After three German invasions in 70 years, the French military wanted the ultimate guarantee of French sovereignty that nuclear weapons would give. SK might think the same way regarding Japan, the former colonizer (a surprising number of Koreans still think Japan has imperial designs on Korea). And of course, SK lives next the Chinese goliath. Should the US alliance with Korea crumble, SK might seek nukes to hedge China.

But little of this is discussed in the Korean media, where most of the nuclear discussion focuses on NK. But I just can’t see SK actually nuking NK.