Recently at 38 North, a blog providing analysis of North Korea, Ralph Cossa had an interesting post discussing two possibilities for providing South Korea with nuclear protection beyond the U.S. strategic nuclear umbrella. First, South Korea could pursue its own nuclear weapons program. Seoul had looked into an indigenous nuclear arsenal prior to signing the Non-Proliferation Treaty in 1975, but gave it up in light of strengthened U.S. security guarantees. Given its robust economy, it could easily restart the effort if it was seen as desirable. The second option deals with the possible redeployment of U.S. tactical nuclear weapons—removed in 1991—to South Korea. Cossa dismisses the idea of a nuclear South Korea as a result of NIMBY (Not In My BackYard) syndrome. But the real question for South Korea is not whether nuclear weapons are desirable, but whether or not they necessarily improve its security vis-à-vis North Korea? The answer is: probably not.
South Korea is at little risk from a major, conventional war—one involving a massive armed invasion—with North Korea. North Korea has made several, relatively smaller attacks on South Korean military assets and on territory disputed by the two regimes. Seoul might consider a nuclear arsenal of its own if it believes the recent minor provocations are a prelude to a major aggressive action by the North, but Lee Myung-bak’s government should not expect that nuclear weapons would stabilize peninsular security to such a degree as to preclude the types of attacks that have occurred as of late.
In all likelihood, a Korean Peninsula with two nuclear states would become a perfect example of the stability-instability paradox first articulated by Glenn Snyder in his 1961 work Deterrence and Defense. The paradox created in a bilateral nuclear relationship means that stability at higher levels of violence (i.e. preclusion of nuclear or major conventional war) can ultimately lead to instability at lower levels of violence. In terms of U.S.-Soviet relations during the Cold War, this meant strategic stability between the superpowers could make nuclear war and major conventional war less likely, but it also made extended deterrence less credible because neither side would risk provoking the other since each side at the ability to obliterate one another. As Robert Jervis explained in The Meaning of the Nuclear Revolution, “Strategic stability creates instability by making lower levels of violence relatively safe and undermining ‘extended deterrence’… the ability of the Soviet Union to destroy the United States means the United States cannot credibly threaten to use its strategic nuclear forces in response to a Soviet attack on West Europe or the Persian Gulf.”
So how does this translate to the Korean Peninsula?
Extended deterrence—which Jervis describes as “…the threat to use strategic nuclear weapons to protect allies”—is not something South Korea needs to worry about. But lower levels of violence are something that must enter into Seoul’s calculations. Given the geographic proximity of the two countries—and the proximity of both capitals—even limited nuclear arsenals on both sides will essentially create a condition of Mutual Assured Destruction (MAD). Just as with the U.S.-Soviet Cold War relationship, while unappealing, the situation may provide a level of stability as each side deters the other and a nuclear exchange is averted. But that certainly doesn’t mean South Korea’s security problems are solved.
The main problem Seoul faces right now is relatively small North Korean provocations. In the past year this has meant the alleged sinking of the South Korean naval Corvette Chenoan or the shelling of Yeonpyong Island. If South Korean had a nuclear arsenal of its own, it is unlikely it could credibly threaten North Korea with nuclear attack since that would mean assuring its own destruction. South Korea could leverage its own nuclear arsenal to conduct operations at lower levels of violence against the North in response to further instigation by Pyongyang, but such tit-for-tat retaliation by either side can inevitably lead to escalation to the strategic level and making MAD essentially a fait accompli.
For its part, the United States is free from the stability-instability paradox in its security situation with North Korea. Washington, both through nuclear and conventional means, possesses an exponentially greater destructive capacity than Pyongyang. Kim Jong-Il’s regime possesses no delivery system capable of striking the United States—despite the perpetual chorus that one is merely five years away. And if North Korea is able to develop a workable ICBM in the near future, even the limited and flawed missile defenses deployed in Alaska and California should be able to defend against the type of smaller attack that Pyongyang would be able to undertake. The stakes would have to be exceedingly high for the United States to undertake such a drastic action as using, or threatening to use, nuclear weapons. For North Korea to be deterred it would have to believe that such an action were likely, and nuclear use in response to incidents like the Chenoan and Yeonpyong Island, while disturbing, do not merit such a response.
Even if tactical nuclear weapons were redeployed to the Korean Peninsula, that doesn’t make it more likely the United States would be willing to use nuclear weapons of any kind in response to the types of provocative actions already cited. Tactical nuclear weapons would be subject to the same limitations a South Korean arsenal would face: the prospect of ensuring Seoul’s destruction in a retaliatory attack from the North. It is hard to see how, even if tactical nuclear weapons were stationed on the peninsula, Pyongyang would view their potential use in response to even deadly attacks like the Yeongpyong Island incident as remotely credible. The United States can maintain its extended deterrent capacity at a distance given its long range delivery capabilities in strategic bombers and ballistic missile submarines—albeit with the understanding that these capabilities will only be useful in dramatic cases where a nuclear attack or major conventional offensive is imminent and not in another Yeonpyong- or Chenoan-type scenario.
There are rarely any good options in play when dealing with Hermit Kingdom. South Korea might be justified in pursuing its own nuclear weapons if it feels that the North is deliberately escalating its attacks, and such a move might deter Pyongyang from expanding its provocations beyond the low level operations it’s conducted over the past few years. But Seoul would also need to be clear about exactly what it was attempting to deter and cognizant of the risks posed by further escalation in the face of such deterrent threats. U.S. tactical nuclear weapons should not be considered an option since they will be of little to no use as an operational weapon, and the deterrent capability to prevent low level attacks is essentially nonexistent. Essentially, more nuclear weapons won’t have much measurable effect on the status quo on the Korean Peninsula.