Will South Korea Have to Bomb the North, Eventually?

As North Korea continues to develop both nuclear weapons and the missile technology to carry them, pressure on South Korea to take preemptive military action will gradually rise. At some point, North Korea may have so many missiles and warheads that South Korea considers that capability to be an existential threat to its security. This is the greatest long-term risk to security and stability in Korea, arguably more destabilizing than a North Korean collapse. If North Korea does not arrest its nuclear and missile programs at a reasonably small, defensively-minded deterrent, then Southern elites will increasingly see those weapons as threats to Southern survival, not just tools of defense or gangsterish blackmail.

During the Cold War, the extraordinary speed and power of nuclear missiles created a bizarre and frightening “balance of terror.” Both the Americans and Soviets had these weapons, but they were enormously vulnerable to a first strike. Under the logic “use them or lose them,” there were enormous incentives to launch first: If A did not get its missiles out of the silos quickly enough, they might be destroyed by B’s first strike. One superpower could then hold the other’s cities hostage to nuclear annihilation and demand concessions. This countervalue, “city busting” temptation was eventually alleviated by “assured second strike” technologies, particularly submarine-launched ballistic missiles (SLBM). SLBMs ensured the survivability of nuclear forces; hard-to-find submarines could ride out an enemy first strike and still retaliate. So the military value of launching first declined dramatically. By the 1970s, both the U.S. and the Soviet Union had achieved enough survivability through various “hardening” efforts that nuclear bipolarity was relatively stable despite the huge number of weapons in the arms race.

The Korean nuclear race does not have this stability and is unlikely to ever achieve it. Nuclear Korea today is more like the Cold War of the 1950s, when nuclear weapons were new and destabilizing, than in the 1970s when they had been strategically integrated, and bipolarity was mature. Specifically, North Korea will never be able to harden its locations well enough to achieve assured second strike. North Korea is too small to pursue the geographic dispersion strategies the Soviets tried, and too poor to build a reliable SLBM force or effective air defense. Moreover, U.S. satellite coverage makes very hard for the North to conceal anything of great importance. North Korea’s nuclear weapons will always be highly vulnerable. So North Korea will always face the “use it or lose it” logic that incentives a first strike.

On the Southern side, its small size and extreme demographic concentration in a few large cities makes the Republic of Korea an easy target for a nuclear strike. More than half of South Korea’s population lives in greater Seoul alone (more than 20 million people), and Seoul’s suburbs begin just thirty miles from the demilitarized zone. This again raises the temptation value of a Northern strike. Both the Soviet Union and the United States were so large, that only a massive first strike would have led to national collapse. In South Korea by contrast, nuking only about five large cities would likely be enough to push South Korea toward national-constitutional breakdown. Given its extreme urbanization and centralization, South Korea is extremely vulnerable to a WMD and/or decapitation strike.

While large-scale North Korean offensive action is highly unlikely – Pyongyang’s elites most likely just want to survive to enjoy their gangster high life – nuclear weapons do offer a conceivable route to Northern military victory for the first time in decades: a first-strike mix of counterforce detonations to throw the Southern military into disarray; limited counter-value city strikes to spur social and constitutional break-down in the South; followed by an invasion and occupation before the U.S. military could arrive in force; and a standing threat to nuke Japan or the United States as well should they intervene. Again, this is unlikely, and I still strongly believe an Allied victory is likely even if the North were to use nuclear weapons. But the more nukes the North builds, the more this threat, and the “use it or lose it” first strike incentives, grow.

It is for this reason that the U.S. has pushed South Korea so hard on missile defense. Not only would missile defense save lives, but it would dramatically improve Southern national-constitutional survivability. (Decentralization would also help enormously, and I have argued for that repeatedly in conferences in Korea, but it is unlikely.) A missile shield would lessen the military-offensive value of North Korea’s nuclear weapons, so reducing both first-strike temptations in Pyongyang and preemptive air-strike pressure in Seoul. Unfortunately South Korea is not hardened meaningfully to ride-out Northern nuclear strikes. Missile defense in South Korea has become politicized as a U.S. plot to dominate South Korean foreign policy (yes, really) and provoke China. (Although opinion may, at last, be changing on this.) Air drills are routinely ignored. And no one I know in South Korea knows where their shelters are or what to do in case of nuclear strike.

Ideally North Korea would de-nuclearize. And we should always keep talking to North Korea. Pyongyang is so dangerous that freezing it out is a bad idea. Talking does not mean we must be taken advantage of by the North’s regular bargaining gimmicks. But we must admit that North Korea seems unlikely to give up its nuclear weapons. The program goes back decades, to the 1960s. Rumor has it that Pyongyang has devoted more than 5 percent of GDP in the last two decades to developing these weapons. The program continued through the 1990s, even as more than a million North Koreans starved to death in a famine resulting from post-Cold War economic breakdown. The North has repeatedly lied and flimflammed to outsiders like the ROK government and the IAEA to keep its programs alive clandestinely. Recently Kim Jong Un has referred to nuclear weapons as the “nation’s life.”

We could even go a step further and admit that a few Northern nuclear missiles are tolerable. If we put ourselves in Pyongyang’s shoes, a limited nuclear deterrent makes sense. Conventionally, North Korea is falling further and further behind. No matter how big the North Korean army gets quantitatively, it is an increasingly weak shield against high-tech opponents. U.S. regime change in the Middle East has clearly incentivized despots everywhere in the world to consider the ultimate security which nuclear weapons provide. The North Koreans have openly said that nuclear weapons ensure their post-9/11 regime security. As distasteful as it may be to us, there is a logic to that. A small, defensive-minded deterrent – say five to ten warhead-tipped missiles that could threaten limited retaliation against Southern cities – would be an objectively rational hedge against offensive action by the U.S. or South Korea. Indeed, this is almost certainly what Pyongyang says to Beijing to defend its program to its unhappy patron.

But this is the absolute limit of responsible Northern nuclear deployment and it is probably where the DPRK is right now. Further nuclear and missile development would exceed even the most expansive definition of North Korean security and takes us into the realm of nuclear blackmail, highly dangerous proliferation, and an offensive first-strike capability. Pyongyang does not need, for example, the ICBM it is supposedly working on.

In this context, my greatest fear for Korean security in the next two decades is North Korean nuclearization continuing apace, generating dozens, perhaps hundreds of missiles and warheads, coupled to rising South Korean paranoia and pressure to preemptively strike. There is no possible national security rationale for Pyongyang to keep deploying beyond what it has now, and if it does, expect South Korean planners to increasingly consider preemptive airstrikes. North Korea with five or ten missiles (some of which would fail or be destroyed in combat) is a terrible humanitarian threat, but not an existential one to South Korea (and Japan). South Korea could ride out, perhaps, five urban strikes, and Japan even more.

But a North Korea with dozens of nuclear missiles, possibly one hundred, some of them on submarines, would constitute a state- and society-breaking, constitutional threat to South Korea and Japan in the event of conflict. That in turn will incentivize pre-emptive airstrikes. Of course, China and the United States might be able to restrain such South Korean action. Unlike the Soviets and Americans in the Cold War, Seoul is uniquely tied to U.S. “permission” to act. In 2010, after two North Korean actions against the South, the then-South Korean president did want to retaliate, but the Americans talked him out of it. Similarly, offensive action against the North that potentially provokes a war – as airstrikes certainly might – would unnerve China, and China’s opposition to South Korean missile defense has already altered that discussion in Seoul. But a nuclear capability of one-hundred missiles is a whole new level of existential threat to the South (and Japan). I find it hard to believe, in lieu of very robust missile defense, that South Korean planners would tolerate this in the long-term. Airstrikes against North Korea have been considered before (1994 and 2010 especially), and this pressure will grow again.

This spiral of paranoia between North Korea nuclearization, and pressure on Seoul (or even Tokyo) to preemptively defang North Korea before it can threaten state-destruction, is entirely predictable – and the reason why everyone, even China and Russia, wants North Korea to stop building. Let’s hope they listen.

Note: This article was first published in The Diplomat