Domestic Debates and Assessment of Extended Deterrence in South Korea: A South Korean Perspective

NAPSNet Special Report

Recommended Citation

Jong Kun Choi, "Domestic Debates and Assessment of Extended Deterrence in South Korea: A South Korean Perspective", NAPSNet Special Reports, April 10, 2012,

By Jong Kun Choi

April 10, 2012

This report was originally presented at the East Asia Nuclear Security workshop held on November 11, 2011 in Tokyo, Japan. All of the papers and presentations given at the workshop are available here, along with the full agenda, participant list and a workshop photo gallery.

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I. Introduction

II. Report by Jong Kun Choi

III. Endnotes

IV. Nautilus invites your responses


I. Introduction

In the following report Jong Kun Choi reviews domestic opinions concerning US extended deterrence to the ROK—including recent debates on South Korea’s nuclear sovereignty— and the diverging perspectives on the issue in South Korean society. Choi argues that the ROK and the US must shift from extended deterrence to tailored deterrence. He concludes, however, that military deterrence (extended and tailored) is not sufficient for resolving North Korea’s nuclear program and weapons. Instead, South Korea and the United States should revive traditional postures of engagement towards the DPRK and exercise strategic patience in order to induce change from within.

Jong Kun Choi is an Assistant Professor in the Department of Political Science and International Studies at Yonsei University.

The views expressed in this report do not necessarily reflect the official policy or position of the Nautilus Institute. Readers should note that Nautilus seeks a diversity of views and opinions on significant topics in order to identify common ground.


II. Report by Jong Kun Choi

-“Domestic Debates and Assessment of Extended Deterrence in South Korea: A South Korean Perspective”

by Jong Kun Choi

I. Introduction

For several decades, even after the Cold War, the practice of containment policy against North Korea left a strong cognitive imprint on the strategic thinking of the Republic of Korea and the United States. The question of what should be done to deter North Korea’s military provocations was mainly focused on the concern that the failure to stand firm against the North would erode the reputation of the ROK-US alliance for containment of potential challenges. Consequently, strategic writings were generally preoccupied with signaling the intention to punish the North even when the stakes were low, which in turn would make the commitment less credible. In addition, the emergence of a nuclear North Korea has prompted the question of whether or not the strategic interests of the US and the ROK are intrinsically identical in deterring North Korea. And the problem is such that predominant strategic theories on deterrence against the North, largely shaped in the context of superpower deterrence, do not always have well-operationalized and ready-answer to what best deters North Korea’s military provocations.[i]

In this vein, as North Korea’s nuclear problem has phased into a stage where the ROK and the US have concerns of not only resolving the North’s nuclear program but also deterring their military provocations including, as claimed by some, a potential nuclear use by the North. Therefore, “extended deterrence” made its first appearance in the joint statement of the ROK-US Security Consultative Meeting (SCM) immediately after North Korea’s first nuclear test in October 2006. The term, extended deterrence, was adopted instead of “nuclear umbrella” as a result of South Korea’s request for a stronger commitment of nuclear defense from the US. However, the full scale discussion on the US extended deterrence began in 2009, and Presidents and Defense Ministers of the alliance have frequently reaffirmed the US commitment to extended deterrence to the Korean Peninsula.

I have three objectives in the paper. First, I will map out a domestic landscape of discussion and debates about the US extended deterrence and show diverging perspectives on it in the South Korean society. Here, a recent debate on South Korea’s nuclear sovereignty will be also introduced. Second, I will assess the problems of the current US extended deterrence concentrating on uncertainty associated with US assurance of nuclear extended deterrence to South Korea. Here, I argue that the ROK and the US must shift from extended deterrence to tailored deterrence by enhancing deterrence by punishment and denial toward the North. Last, I conclude by saying that military deterrence including extended and tailored is only a necessary foundation for resolving North Korea’s nuclear program and weapons. A sufficient strategic stance is to revive the traditional posture of engagement towards the North and exercise strategic patience for inducing the North’s change from within.

II.      Mapping the Domestic Politics of US Extended Deterrence in South Korea [ii]

South Korea Debates Over US Extended Deterrence

Majority of the security community in Seoul is content with the US commitment to the extended deterrence. Mainstream conservative security community consisting of security experts and officials contends that South Korea’s reliance on US extended deterrence including the nuclear umbrella is inevitable given the conventional and nuclear threats from the North. These people essentially agree that the crux of the matter is to showcase the strong standing of the ROK-US alliance through the US extended deterrence commitment. They have welcomed the US reaffirmation on its commitment of extended deterrence including nuclear umbrella throughout 2006~2011. They perceive that South Korea, lacking nuclear and conventional capabilities, must be able to rely on the US extended deterrence. Strengthening ROK’s alliance with the US is not only the virtue; it is the mission of the government as a only certain way to ensure Seoul’s security. This perspective tends to be supported by the conservative section of the political orientation (a.k.a. Members of the Ruling Party, National Security Officers in the Blue House, the Veteran’s Association).

Those moderate security conservatives who see the use of nuclear weapons as unrealistic and implausible both by the US and North Korea in the Korean peninsula argue that the US extended deterrence must be able to lay out detailed plans for the conventional deterrence in limited and expanded conflict situations. Otherwise, they argue, the political commitments to the extended deterrence by the US and appraisal by the ROK government become nothing more than a political rhetoric causing credibility problems, a serious foundation of deterrence strategies. These groups constantly demand to clarify the scope of roles that the US may or may not play in North Korea’s limited provocations. Concentrating the deterrence strategy on North Korea’s full blown invasion is like spending all the strategic energies on the least possible event such as a full invasion by the North, overlooking more possible and realistic incidents such as limited military provocations by Pyongyang. These people tend to be military planners and high ranking junior officers in the ministry of defense.

Moderate liberal security experts argue that South Korea must be able to play its own role curtailing North Korea’s provocations through upgrading its power projection capabilities. They argue that South Korea should be able to improve its own surveillance and precision-target capabilities and update its military organizational structure on par with its new challenges and opportunities while under the US extended deterrence. They doubt whether or not the US commitment to extended deterrence is real; the US commitment is not bound by any legal frameworks obligating the US to provide military aides to Seoul.[iii] Some critics argue the liability of the US extended deterrence to the Korean peninsula. Although the US commitment has been iterated at the summits and ministerial meetings, the critics argue that it is merely declaratory lacking actual manuals for implementation of deterrence measures. Especially with nuclear deterrence, South Korea has to rely only on the US political commitment since the United States would not discuss terms of nuclear deterrence since the United Strategic Command (STRATCOM) is in charge of nuclear weapons under direct orders from the US President. They argue that Seoul’s over reliance on the US extended deterrence merely constraints South Korea’s strategic maneuverability especially after the reinstatement of South Korea’s full command and control in 2015. These people used to be the mainstream security actors back in the Roh Moo Hyung administration and now advise the opposition parties.

Experts on the inter-Korean relations, especially those who believe that comprehensive engagement should be the default policy towards the North, argue that the commitment of “extended deterrence” could become a pretext in North Korea’s demand for nuclear disarmament negotiation between the US and North Korea when the daunting task should be about dismantling the nuclear program in the North. Strategic emphasis on nuclear deterrence blurs the foundational motives as to why South Korea and its neighboring states have laboriously negotiated with North Korea. Repetitive confirmation on the need of extended deterrence will only strengthen, if not justify, North Korea’s nuclear development. Extended deterrence brings the dilemma of self-contradiction. Officially, ROK and the US do not accept North Korea as a nuclear state while extended deterrence including the nuclear umbrella is based upon the premise that North Korea in fact possesses nuclear weapons and can use them. Furthermore, the promise of extending deterrence through the US nuclear umbrella contradicts the efforts towards the denuclearization of the Korean peninsula through the Six Party Talks.

Table 1. Mapping the Security Community in South Korea

Credibility of US Extended Deterrence Threat Perception of Nuclear North Korea South Korea’s Defense Capability
Conservative Very Credible on nuclear and conventional Very High Must work with the US within the alliance structure.
Moderate Conservative Credible but requires more precise planning Moderate Should rely on the US but eventually acquire independent force capability.
Moderate Liberals Diminishing Moderate Must work towards its own independent force capability as soon as possible.
Liberals Credible Low

South Korea’s Nuclear Sovereignty Debate as Unintended Spirals of Extended Deterrence

With North Korea’s nuclear tests and US commitment to the extended deterrence, conservative politicians and nationalistic columnists [iv] gradually ventured conjectures on South Korea’s independent nuclear capability, which has long been regarded as taboo to even talk about. This is so called “nuclear sovereignty” arguments. They essentially argue that South Korea’s vulnerable national security can only be improved by its own nuclear capability. Moreover, South Korea cannot infinitely rely on the US commitment, which they perceive can change any time. North Korea’s nuclear tests and the lingering processes of the Six Party Talks only proves that North Korea will not give up its nuclear capabilities and the US extended deterrence is not effective in deterring North Korea’s potential provocations. Thus, they promote South Korea’s independent nuclear deterrence vis-à-vis North Korea. These ‘nuclear sovereignty’ arguments remain as a minority perspective, which is constantly challenged in terms of its feasibilities.[v] Among these groups, less ‘extreme’ argue that South Korea’s drive for, not actual possession of, its own nuclear capabilities, will enhance its negotiation leverage against North Korea and upgrade South Korea’s strategic value to China.

However, what’s noticeable is the emergence of peaceful nuclear sovereignty argument. This group rejects the idea of possessing nuclear weapon. Rather, South Korea should be able to construct the fuel cycle – enrichment and reprocessing of nuclear material for energy generation. Since South Korea currently generates about 40 % of its electricity through 21 nuclear power plants across the nation, it should be able to reprocess the spent-fuels for recycling. The current constraints imposed by the US are too rigid, they argue. They demand that South Korea should be able to enjoy nuclear sovereignty to the same extent as Japan. Nuclear scientists, science journalists and energy-industrialists support this perspective.

III. Assessing US Extended Deterrence

Signaling Too Much Lowers Credibility

Stable deterrence comes from the ability to prevent something that other actors want to do through either punishment or denial.[vi] Even if a state prefers to use military means to change the status quo in a crisis, it simply cannot do so due to punitive mechanisms imposed by the deterrer. Punishment includes the target state’s second strike capabilities as well as its credible commitment to impose enormous costs on the initiator more than the initiator could sustain.[vii] And both must know that the benefit of the first strike is uncertain and the retaliatory second strike by the target state is more certain, and the cost may be unbearable. Any direct attacks on a target state by an initiator can be prevented through direct deterrence. Deterrence commitments can also be made for a target state by an ally, which is called extended deterrence. The ally can signal its strong commitments by installing its military forces nearby a would-be initiator, which functions as a tripwire activating an automatic dispatch of forces. As a result, each side would be very reluctant to launch the first strike since the cost of the counter attack by a target state may overshadow the benefit of the first strike by an initiator.[viii] The core of deterrence theory during the Cold War was meant to provide a logical program for the age in which stability of international system and state’s survival rested on “the irrationality of the rational” logic of nuclear threats. The situation was simple; two states imposed threats of mutual annihilation if one or the other launched a nuclear attack. Therefore, if either side’s home territory was attacked, the responsive action would be predictable, that is to retaliate with nuclear forces.[ix]

However, extended nuclear deterrence becomes problematic when the traditional ally faces a nuclear threat from a rogue state in protracted conflictual relations. The problem is to formulate credible measures to deter the ally’s enemy from venturing military attacks. Furthermore, the related problems essentially come down to operationalization and formulations of the details of deterrence in a totally new strategic environment. How could the deterrer extend its deterrence to its opponent with the same level of commitment in a strategic situation defined by the ally’s enemy? How could the deterrer overcome the difficult task of persuading its adversary that it would be willing to endure disproportionate political and strategic costs and to stand firm by its ally? Without such considerations, the reputation by the deterrer for strong resolve would be compromised. And the adversary may perceive any threats of punishment less credible.

In a deterrence relationship, effective deterrence means that each side possesses enough retaliatory capability to inflict costs on each other that outweighs the benefits of an initial attack that may change the status quo.[x] Here again, the reputation for resolve to make a retaliatory threats credible is the key. Thus, effective deterrence requires actors value the status quo (a.k.a.: absence of war) than even victorious but costly change of the status quo.

It appears that the contents of the US commitment to extended deterrence for Korea do not showcase new elements. Korea has been under the nuclear umbrella in conjunction with conventional forces and missile defense provided by the United States. Thus, the US extended deterrence is not fundamentally different from the traditional deterrence, although one may assert that the term “extended” may imply a larger scope and intensity of deterrence, confirming and strengthening the US credibility in times of North Korea’s nuclear era. But analytically speaking, it is difficult to pin point what the differences are in essence. Therefore, the emphasis of US extended deterrence in the Korean Peninsula does not have to be comprehensive; it should focus on conventional deterrence measures and send out credible and realistic signals to the North that any type of provocations will be met with firm deterrence measures. Nuclear weapons have been also proved to be obsolete in terms of deterring non-state terrorists. Likewise, the US threats to use diplomatic sanctions and military means vis-à-vis the North have thus far failed to dissuade and deter Pyongyang from furthering its nuclear programs and venturing limited provocations.

For the United States, deploying nuclear weapons against North Korea is least plausible given the geopolitical sensitivity. On the other hand, North Korea’s use of nuclear weapon is physically limited since it lacks delivery technology and will be shot down in mid-air by the missile defense system. Moreover, an outbreak of full scale war makes the use of nuclear weapon on both sides virtually impossible. From the US perspectives, it runs the risk of devastating the Korean peninsula and contaminating the Japanese islands, Manchuria of China and the Kamchatka peninsula of Russia with nuclear fall-outs. North Korea cannot also use it for the same reason and will face the harsh international criticism for breaking out the nuclear taboo and has to risk its survival as state.

All these factors point to the fact that emphasizing the potential use of nuclear weapon does not necessarily enhance the US commitment to extended deterrence. The nuclear deterrence worked during the Cold War since the nuclear balance of terror marked by mutually assured destruction essentially constrained each other’s behaviors. And any threats to use the second strike deterrence were persuasive due to the irrationality of the rational. In short, extended deterrence was credible then as nuclear attacks on Europe was seen identical as an attack on the American soil and vice versa. Currently, one must be able to assess if the US could maintain the same attitude; that is, can the US treat any nuclear attack on Seoul same as an attack on the US soil? Can the United States trade Seoul for Beijing or Tokyo? All comes down to credibility. Deterrence commitment becomes credible when the deterrer makes a credible commitment permitted within the boundary of its capability and do-ability. Signaling too much kills credibility.

Tailoring Extended Deterrence

While the interactive dynamics between an initiator and a defender may produce something resembling a descending spiral of security dilemma, as long as absence of war is sustained through mutual deterrence, one can say that crisis stability is maintained.[xi] Therefore, despite the rise of threat to one’s security, crisis stability can be maintained when each state is capable of punitive second strikes and a potential initiator refrains from launching the first attacks due to the high cost of war, low probability of winning and, mostly, high probability that the target will retaliate. All in all, crisis stability is delicate; peace may be unstable and sporadic crisis could occur. In the Korean Peninsula, both the ROK-US alliance and North Korea are effectively deterred. Both sides acknowledge that each side is deterred by the high cost of war. Thus, it can be said that the high cost of war offset the low credibility of credibility. A classic example is the constant bluff by the North to declare war whenever Seoul and Washington pressure the North during the heightened diplomatic standoffs. On the same note, South Korea could not proportionately retaliate the North in the sinking of Cheonan vessel and shelling of Yeonpyong in 2010 in fear of crisis escalation to a full scale war.

Instability in deterrence becomes visible when a propensity for unintended crisis escalation gets larger. This means that states in deterrence dyad are seriously paranoid with a surprise attack by the other, and overreacts with any threats from the other actor. Thus, a crisis gets easily out of hand and spirals into major conflict. On the other hand, stability in deterrence is increased when both actors know that even a successful surprise attack would not change the outcome of war and believe in confidence that they can win. In this situation, each will wait out in prudence. Thus, a crisis does not easily go into a descending spiral. Deterrence in the Korean Peninsula is effective and getting stable. In reality, both sides do not strongly want to change the status quo through the use of full force for unification. They tend to behave rather prudently and refrain themselves from impulsive reactions even in a limited military provocations. This was clearly demonstrated during the Yeonpyong shelling.

Therefore, what matters the most in stable deterrence is not an initiator’s credible threat to attack but a defender’s firm commitment to punish the first attack. The key aspect of deterrence is to make other think it is going to stand firm and punish with a realistic and more probable outlet of force. Not only is it a cost-imposing strategy but also a successful deterrence makes the other think that it will lose. Thus it is about signaling intentions – not just estimating enemy intention but influencing them. The core of credible deterrence is not only about how to communicate with enemies and but also about what to convey to make them think that you are committed.

If we acknowledge that more realistic probability should be assigned to limited conflicts than a full scale war, then the ROK-US alliance must be able to craft and tailor new deterrence postures that constraint North Korea’s venturing behaviors with higher credibility of threat while making diplomatic leeway for securing stability in the Korean peninsula. Rather, for enhancing the credibility of the US extended deterrence, the United States should be focusing on supplementing South Korea’s deterrence capabilities by providing more rigorous intelligence and information services.[xii] It should also be able to lay out strict and rigid standard operating procedures of intra-alliance military cooperation in times of limited military provocations that resembles Yeonpyong.

The US should adjust its extended deterrence to reflect the strategic reality of the Korean Peninsula and Northeast Asia and match North Korea’s motives and South Korea’s deterrence capability, which will increase the US deterrence credibility and minimize strategic uncertainty. Thus, the daunting task ahead for the US and ROK is not about maintaining large conventional forces but about rebooting their strategic mindset and tailoring extended deterrence to make it more credible.

IV. Conclusion

The current US extended deterrence to Korea commits too much in times of relative decline of the US, thereby lowering its credibility. Moreover, the object of deterrence, that is to prevent and punish the North’s all out invasion, is too out-fashioned, therefore unrealistic. The US and ROK must be able to tailor its extended deterrence and reshape the challenge delivered by Pyongyang.

First, they must be able to signal absolute intolerance to nuclear proliferation beyond the Korean Peninsula. For this, both must be able to present and signal realistic deterrence postures to Pyongyang. Second, Seoul must be able to upgrade its strategic mindset that it is Seoul that must play the major role deterring Pyongyang while subsidizing the role that the US have assumed. It has to be able to update its force structure to effectively project its punitive capabilities by enhancing its air-force and C4I. Third, tailoring the current extended deterrence must be able to focus on enhancing the conventional deterrence by clearly laying out the deterrence plan for limited military provocations that resemble naval skirmishes and shelling in the NLL of West Sea.

All in all, deterrence had to be firm and cannot loosen up by relying too much on a wishful thinking that the North is getting weak. Security insensitivity may cause unexpected surprising attacks. On the other hand, security sensitivity oftentimes causes descending spirals of conflicts leading to unintended consequences. Thus, prudence and patience are the virtue, which can only be affordable with strong and credible deterrence.

The discussion thus far reminds us of the importance of engaging diplomacy even towards enemy states. Engagement helps us figure out their intention and motives, which are crucial components for formulating one’s own deterrence postures. Deterrence is perhaps a necessary variable for absence of war. Certainly, it does not automatically bring us active peace that we do not even have to worry about deterrence at all as in the Franco-German and Canada-the US relations.

Deterrence has been successful in the Korean peninsula, but has not brought what we wanted. We must be able to acknowledge that the North Korean system was designed to withstand pressure. The history shows that it has survived critical junctures of changes including the end of the Cold War. What drives the North more aggressive externally and cohesive internally is the hostile environment. On the other hand, the North has no defense against friendly engagement stances from the outside. If the North is built to sustain external pressure and has functioned well in hostile international environments, then the only logical course of action from the rest of the world is to be “friendly.” Therefore, if North Korea has no defense against friendly behaviors, then rational actors should stick with engagement policy vis-à-vis the North. Again, engagement toward the North will sufficiently shift our future towards more optimistic ones while tailoring the deterrence contributes to maintaining the status quo.


III. Notes

[i] Robert Ross, “Comparative Deterrence: The Taiwan Strait and the Korean Peninsula” in Alastair Iain Johnston and Robert Ross, eds. New Direction in the Study of China’s Foreign Policy (Stanford: Stanford University Press, 2006), pp. 13-49.

[ii]This section was written after interviews with security experts in privacy. For this purpose, I do not refer to their names and positions. Some of the names are also well known. I left their identities anonymous for fair treatment.

[iii] Outside of the security community in Seoul, Jeffery Lewis pointed out this problem first. For his argument, see Jeffrey Lewis, “Rethinking Extended Deterrence in Northeast Asia”, Nautilus Institute, NAPSNet Policy Forum 10-054( November 3, 2010), internet-document available at

[iv] For the most influential conservative column, see  Dae-jung Kim, “South Korea’s nuclear possession will make the North to the negotiation”, Chosun Ilbo, January 10, 2011.

[v] For the most telling criticism, see Chung-in Moon, “No Time For Nuke”, Korea JoongAng Daily, May 10, 2011. Internet Document Available at

[vi] Thomas Schelling, Arms and influence (New Heaven: Yale University, 1966), pp. 69.

[vii] Glenn Snyder, Deterrence and Defense: Towards a Theory of National Security (Westport: Greenwood Press, 1961), pp.14-16; Steven J. Brams and D. Marc Kilgour, “Threat Escalation and Crisis Stability: A Game-Theoretic Analysis”, the American Political Science Review, Vol.81, No.3 (September, 1987), pp. 833-850.

[viii] Robert Powell, “Crisis Stability in the Nuclear Age,” American Political Science Review, Vol. 83, No.1 (March 1989), pp.61-76.

[ix] On general deterrence, see Patrick Morgan, Deterrence Now (Cambridge: Cambridge University Press, 2003), ch.3.

[x] Thomas C. Schelling, the Strategy of Conflict (New York: Oxford University Press, 1963), ch.9; Thomas C. Schelling, Arms and Influence (New Heaven: Yale University Press, 1966), ch.6.

[xi] Barry R. Posen, “Crisis Stability and Conventional Arms Control,” Daedalus, Vol.120, No.1 (Winter 1991), pp. 217-232.

[xii] M. Elaine Bunn, “Can Deterrence be Tailored?” Strategic Forum, No. 225 (January 2007), pp.1-8; Patrick Morgan, “Evaluating Tailored Deterrence,” in Karl-Heinz Kamp and David S. Yost, eds., NATO and 21st Century Deterrence (Rome : NATO Defense College, 2009),, 32-49.


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