US-ROK Deterrence Architecture

The North Korean nuclear and missile threat has been rapidly increasing especially since 2017. During this past year, US intelligence agencies released two major new assessments of North Korea’s intercontinental ballistic missile (ICBM) capability that are different from the past ones. The first assessment reduced the time in which North Korea is expected to achieve the ability to attack the US mainland from three or four years to within a year.¹ At the end of 2017, another report claimed that the rogue regime will achieve nuclear-tipped ICBMs within only three months.² This rapid increase in threat poses a critical challenge to the ROK-US alliance, which has been the key factor in successfully deterring another war on the peninsula since the Korean War.

Uncertainty remains. First, much is still unknown about nuclear deterrence in the absence of historical evidences and reliable theories.³ Second, North Korea is one of the least known regimes in the world, and the rationality of the dictator is still highly debatable.⁴ Third, the two allied countries experienced political transitions in 2017, and the suspicion toward each other is still relatively high,⁵ even though the new administrations often strove to create a good foundation for their relationship in the first year.

North Korea should be denuclearized. However, it is highly likely that it will take a long time to finally accomplish this. The military option, which involves attacking North Korea preemptively, cannot be South Korea’s choice, because its goal is peace. and there is undeniable risk that military conflicts would ensue and possibly lead to a nuclear exchange. Still, surrendering to the rogue regime’s military ambitions by admitting the North as a de facto nuclear state should not occur. The Asian classic, Sun Tzu’s The Art of War, explains that the highest strategy is not to fight and win, but to win without a fight.⁶ The right strategy can frustrate the enemy to surrender even without any conflict.

It is critically important for the alliance to build more reliable and stronger deterrence architecture to effectively deal with the North Korean military challenge because it will provide an unshakable foundation for the denuclearization negotiations, which may last for a considerable time. To support this effort, this article first identifies the primary challenges faced by the alliance. Second, it covers some main issues the alliance should address when designing the new architecture. Third, this article presents three directions that the alliance should take as part of closer cooperation. Finally, it concludes with some recommendations.

Challenges

The current defense and deterrence on the Korean Peninsula is basically founded on the “ROK-US tailored deterrence strategy,” which is primarily powered by US extended deterrence.⁷ The concept of tailored deterrence was created to deal with various situations in different regions more effectively. Therefore, it stressed the importance of intimate and good communications between the allies. The term ‘tailored’ signifies that the alliance continues to tailor the best-fitted deterrence posture through close coordination, including regular senior meetings and combined table top exercises (TTX).⁸

Ideally, while experts in both countries are continuing strenuous debates on assessing the security environment and military balance and on the most effective ways to counter the major military threat, the officials of the ROK Ministry of National Defense (MND) and US Department of Defense (DOD) will keep exchanging perspectives and shape mutually agreeable policies on deterrence posture by utilizing experts’ arguments and reflecting on public opinion. The success of a tailored deterrence heavily depends on a mutually shared understanding of the current situation and effective countermeasures.

The rapid increase in the North Korean nuclear and missile threat is raising unique challenges to the alliance. For many years after North Korea was publicly known to have a nuclear program, South Korea and the United States had a tendency to ignore or underestimate its nuclear capability, worrying that if the alliance took full-scale countermeasures against a North Korean nuclear threat, North Korea might be considered by others and by itself as a nuclear state. As a result, professional debates have been limited, and the general public is not well informed on related issues.

Nuclear deterrence is a research subject with inherent limitations, since there are not enough historical cases by which reliable theories can be tested.⁹ Additionally, since the demise of the Cold War, the main theme of studies on nuclear weapons has been centered on nuclear non-proliferation and arms reductions.¹⁰ Nuclear deterrence has been only a minor issue for the last two or three decades. Moreover, nuclear deterrence against North Korea might be defined as a new theoretical theme in some respects. North Korea is a small and rogue regime that is different from countries like Russia and China, which are US peer competitors; therefore, a stable, strategic mutual deterrence is not certain to happen between the United States and North Korea. North Korea is also different from India, Pakistan, and Israel, which are focused on only their regional rivalries. It is a second-tier nuclear adversary directly targeting the United States. No one can be confident that preexisting theoretical perspectives can be applied to the North Korean case before being properly tested.

Both South Korea and the United States experienced a power transition in 2017. President Donald Trump was not a candidate from the political establishment and declared a fundamental change in US foreign policy; uncertainty has been very high over the past year and appears to continue. The Moon Jae-in administration was inaugurated 7 months earlier than typical as a result of the unprecedented impeachment of Park Geun-hye. It was also a power transition from the conservatives to progressives for the first time in nine years; so, the uncertainty about South Korean policy toward the United States and North Korea was also estimated to be high.

The two governments developed a good foundation for a mutual relationship in 2017 in spite of several concerns regarding possible conflicts of interests. Trump stressed the importance of the alliance by both expressing it himself and having his secretaries repeatedly confirm that.¹¹ Moon tried his best to build a good relationship with Trump and expressed very clearly his will to strengthen the alliance.¹² Finally, the two successfully reduced uncertainties toward each other, especially through a series of meetings and regular communications among major decision makers including the two presidents.

Some concerns and uncertainties still remain. Both governments have a strong will to denuclearize North Korea; however, the two countries seem to have a somewhat different approach to the problem. While South Korea stresses the importance of a diplomatic resolution of the problem in order to keep the balance between pressure and engagement, the United States focuses on maximum pressure with an emphasis on not repeating failed methods of denuclearizing North Korea and being deceived again.¹³ The two possibly disagree when and under what conditions the negotiations with North Korea can begin.

Moreover, there is some possibility that disagreement between the two countries will grow over time. As North Korea becomes closer to improved ICBM capabilities, the nature of the North Korean problem is changing. In the past, it threatened South Korea and Japan, two key US allies; so, it was essentially a matter of broad US national interests, even though it was related also to the global non-proliferation regime. However, since North Korea is publicly declaring that it can directly attack the US mainland with nuclear-tipped ballistic missiles, the problem is threatening core US security interests. When missiles could only target US allies, it was primarily at the allies’ discretion as to how to respond since this affected directly their security interests and only broadly US national interests. However, after it was realized that the North was becoming closer to an ICBM capability over time, the allies anticipate that, at some point, the United States may dictate how to address the North Korean problem, and the allies will not be able to block it since the threat compromises core US national security interests.

Although the North Korean nuclear and missile program is threatening the United States and its allies at the same time, the priority of policies to address it can differ. For example, the military option is not an acceptable choice for South Korea and Japan since it is almost certain that North Korea will retaliate in some way (nuclear/conventional) causing unacceptable casualties and damages. However, the United States may prefer the military option because it is better than allowing North Korea to finally accomplish its goal of ICBM capability to attack the US mainland, which would make military options permanently impossible.

North Korea’s ICBM capability raises another question to US allies regarding the “decoupling problem.” One of the most essential foundations of the alliances between the United States and other countries is extended deterrence, and the North Korean ICBM may damage it. If North Korea finally accomplishes its nuclear and ballistic missile program, it may be able to threaten the United States into not retaliating even if the North invades and attacks US allies. Due to that risk, South Korea and Japan may be urged to create their own nuclear weapons, which the United States could not accept because it would devastate the global non-proliferation regime. Actually, this problem remains uncertain since the North Korean nuclear and ballistic missile capability has not yet been tested well enough and the US missile defense may be able to intercept a strike. However, deterrence is a psychological phenomenon, so decoupling remains a potential problem to the alliance if the public is not well-informed.

Tasks

For the development of a combined deterrence architecture, which will be built through the cooperation of South Korea and the United States, the two need to have a shared perspective on the current military balance on the Korean Peninsula and on the main theoretical points of deterrence, since those are the foundations for designing the architecture. However, as mentioned previously, major issues related to North Korea’s nuclear capabilities and strategies and deterrence against North Korea are still highly debatable. This article does not aim to conduct a full-scale analysis of those issues but attempts to identify the most important issues for that analysis and present some basic criteria for considering those issues.

First, the capability of North Korea needs to be assessed despite limited information. The most basic data of North Korea’s nuclear capability, the number of nuclear warheads, is still unknown. David Albright assumed that the North had roughly 13–30 warheads as of the end of 2016.¹⁴ Siegfried Hecker recognized the number as 20–26.¹⁵ There are many other studies arguing that the regime has far more warheads, considering it developed uranium enrichment technology.¹⁶

The North Korean missile capability is far more debatable.¹⁷ It has successfully demonstrated the distance of its missiles’ reach by a series of launches, especially since 2016. However, most of them were conducted at a high angle; therefore, their real wartime capability has not been tested yet. It is generally perceived that it will take additional time for the North to achieve the re-entry technology.

The manner in which the North will employ its nuclear capability is one of the most important issues; yet, it is one that is still far from drawing agreement. Some experts argue that the country only seeks regime survival, and its aggressive behavior just reveals its vulnerability.¹⁸ Others contend that North Korea has a more ambitious goal of conquering the entire Korean Peninsula and denying US operational access to the peninsula. With its ballistic missiles, North Korea could attack not only US naval and air force bases in Guam and Hawaii but also harbors in South Korea where the US reinforcements would land. Perhaps, North Korea has not decided its own strategy yet, since it has focused its energy on making nuclear weapons and missiles until now.

The North Korean nuclear command and control is also very important for deterrence and difficult to understand. Since the regime is the world’s worst totalitarian system, it is very important to be able to threaten the dictator himself to deter North Korea. For the North, it is better to delegate nuclear command and control to the lower-level commander in the battle field for the survival of nuclear weapons in an emergency. However, no one has confirmed whether this is possible in North Korea.

South Korea and the United States do not have many shared perspectives on the major issues related to North Korea’s nuclear capability and strategy. North Korea’s threat should not be underestimated, but rather overestimated, since nuclear weapons are so fatal. It would be difficult to ignore the criticisms based on the worst-case scenario in the process of rational decision making that is directly related to national security.

The following theoretical questions need to be answered when developing a deterrence architecture. The first is whether North Korean nuclear weapons could be deterred only by another nuclear warhead or by conventional weapons, because retaliation could be effective with highly developed conventional weapons systems. Since the Korean Peninsula is relatively small, has limited theater, and is already populated with large and highly lethal conventional weapons, the role of nuclear weapons in the overall deterrence architecture may not be that high. South Korea is vulnerable to the large conventional threat from North Korea, including about 8400 artillery pieces and 2800 MLRs near the DMZ. North Korea can fire 10,000 shells over Seoul in the first minute of an attack.

Nuclear weapons are the most powerful weapons in the world; so, they are assumed to have the best deterrence effect. However, they have their own vulnerability. First, their credibility, a critical factor in deterrence, is lower than conventional weapons since it would be difficult to use nuclear weapons in reality, i.e., the nuclear taboo. Especially on the Korean Peninsula, there is much concern regarding radiation damage, and as a result doubt that nuclear weapons would be used in reality can be relatively high. With the development of low-grade nuclear weapons, the concerns about radiation effects could be lowered.

Extended deterrence has additional vulnerabilities. As North Korea comes close to achieving an ICBM capability, doubts rise that the United States would not protect South Korea given that the country may not take the risk of sacrificing its own citizens by using nuclear weapons on North Korea. Some describe the situation as “decoupling.”¹⁹ Actually, it is not easy to estimate whether decoupling would occur or not because North Korea’s level of technology is very low and US missile defense can work. However, substantially more South Korean people are beginning to worry about the decoupling situation, especially after US intelligence agencies released new assessments of the North Korean nuclear and missile capability in 2017.

Since many people in South Korea believe that only nuclear weapons can deter a nuclear-capable North Korea, almost 70% of respondents in some polls were in favor of the redeployment of tactical nuclear weapons on the peninsula.²⁰ Those polls were conducted when the support for Moon was higher than 70% and the Moon administration clearly declared its opposition against redeployment. South Koreans’ perspectives on nuclear deterrence is that nuclear weapons cannot be deterred by any other means, and anxiety over decoupling surpassed the support of Moon, which has been falling.

The second question is how to combine the deterrence by denial and deterrence by punishment in the overall deterrence mechanism against North Korea. Deterrence is defined to dissuade the enemy from provoking by denying the success of the provocation or punishing it as a revenge after it provoked. It is ideal to strengthen both simultaneously. However, in reality, it is impossible due to the lack of resources; the manner in which the two are combined should be carefully chosen. South Korea has developed its own deterrence mechanism, the 3 Ks, which refers to “Kill Chain,” “Korean Air Missile Defense” (KAMD), and “Korean Massive Punishment and Retaliation (KMPR).” KAMD is a typical form of deterrence that uses a denial component, and KMPR is a type of deterrence by punishment. “Kill Chain” signifies the strike system to detect the enemy’s launcher and attack it before it fires. So, it has both deterrence by denial and deterrence by punishment characteristics simultaneously.

Generally speaking, deterrence via a denial mechanism is very expensive to build and fairly incomplete. This is due to it being highly difficult to intercept the ballistic missiles and the enemy’s continuous attempts to develop various avoidance technologies. Deterrence by denial also runs into a “numbers problem.” If the enemy attempts an attack with many missiles simultaneously, it is almost impossible to deny them all.

Deterrence by punishment has its own weaknesses. Its essence is retaliation, and the core of retaliation is to eliminate the enemy’s valuable assets. While South Korea has many more valuables to protect (i.e., cities, industries, population), the North has only a limited number of targets. Since the survival of Kim Jung-un and power elites is the core interest of the North Korean regime, they need to be targeted; however, to track them and penetrate the well-developed underground facilities is not an easy task.

On the other hand, deterrence by punishment has many advantages. It is far cheaper than deterrence by denial, and a deterrence by punishment mechanism can impose a cost on the enemy, who needs to build its own defense against the punishment attack. So, the deterrence architecture that is focused on a deterrence by punishment mechanism is economically efficient in a long-term competition with the enemy.

The third question is how to keep the balance between deterrence and crisis management. As North Korea is achieving nuclear capability, crisis management becomes increasingly more important since any military conflict can lead to a nuclear exchange potentially. As a result, crisis management is an important factor that should be seriously considered in designing a deterrence architecture. Some deterrence mechanisms can have a negative effect on crisis management. For example, “Kill Chain” has a strong deterrence effect since the enemy cannot confirm that it can succeed in launching the missile. However, it has a destabilizing effect at the same time. It can force the enemy to use its nuclear weapons before being attacked in an emergency, a “lose or use” dilemma. Some deterrence measures should be limited to a certain level lest the destabilizing effect exceed the deterrence benefit.

Directions

In the past years, the alliance defense policies against North Korean provocations have been limited to continuation of ad hoc reactions as opposed to “the big picture,” which looks ahead to North Korean future provocations. Some countermeasures lost most of their military effectiveness even before they were completed. “Kill Chain” was designed to strike the North Korean missile launcher during its preparation roughly within a half an hour. However, as North Korea introduced solid fuel ballistic missiles and reduced the preparation time dramatically, the Kill Chain was not expected to deal with them. In addition, if North Korea achieves SLBM capability, the Theater High Altitude Air Defense (THAAD) system may not be able to cover the range, which was originally expected, since the North could launch a missile from the southern part of the Yellow Sea.

The grand design of a deterrence architecture needs to be mapped out to overwhelm the North Korean plans and the timetable to develop its nuclear and missile capabilities. From a strategic perspective, the roadmap that the North would pursue from now can be anticipated, albeit not in detail. The best reaction is not to react when the North introduces a new system or capability, and displays it provocatively, but to present a long-term grand plan to deny all the military capability that the North strives to possess even before they introduce it.

If North Korean military aspirations and its future vision can be disturbed in advance by this grand plan with the toughest economic sanctions and political isolation, its nuclear and missile capability can be relegated to be only a burden. The debates on the use of a military option as a solution to the North Korean problem can also cease, as there is a highly effective and safe alternative. The grand design to strengthen a deterrence architecture on the Korean Peninsula is expected to be effective to force China and Russia to do more for North Korean denuclearization.

For this grand design to go forward, South Korea should concentrate its national power to dismantle the North Korea’s nuclear ambitions in a more systematic way. It should make the North realize that nuclear weapons bring more of a cost than a benefit. It should use its military power to impose more costs on the North’s nuclear armament.²¹ This idea can be called a “cost imposition strategy.”²² The design of “cost imposition measures” is very important for this. They can be designed considering DIME (Diplomacy, Intelligence, Military and, Economy) factors, and this article concentrates on the military ones. South Korea can use its military capability to force the North to abolish its nuclear weapons as below;

First, increasing the South Korea’s protection capability from North Korea’s nuclear weapons is not only good for protecting the South but even better to impose more costs on North Korea. South Korea can use KAMD also as a cost imposing measure. If this system were completed, North Korea would have to think about how many of its missiles could reach their targets. The North would try to increase the number of missiles and acquire technologies to penetrate the KAMD system, paying for additional missiles and new technologies.²³

Second, enhanced counter force capability can be one of the cost imposition measures. There are two options for South Korea’s counterforce strategy. One is a direct strike on North Korea’s nuclear weapons and facilities, i.e., destruction. As Austin Long and Brendan Green argue, the current state-of-art weapons and censorship is able to find out the location of North Korea’s nuclear weapons and facilities and strike them with very high accuracy. It could decrease the survivability of the North’s nuclear weapons. Faced with this, the North would have greater hardship to maintain its nuclear forces, given the need to increase its nuclear arsenal and diffuse nuclear command authority, complicating command and control over its nuclear forces.²⁴

The other option is to impede the North’s nuclear missile launches, i.e., disruption. Recently, North Korea has shortened its nuclear missile launch time to a dozen minutes.²⁵ However, missiles have to be fired not far from shelters in order to avoid exposure to ROK-US surveillance assets and shorten launch times. If the ROK-US force located the missile shelters, the ROK could fire EMP and Jamming weapons near the shelters to disable communications related to the launch process or deploy large quantities of drones and smart landmines. In this case, North Korea would be apt to build more unrevealed shelters to hide its launchers, enhance the anti-jamming capability of missile shelters, and deploy more air defense system to protect shelters from the South Korean drones. This option possibly not only impedes the North’s missile launch but also imposes more costs on it to maintain a missile’s survivability.

Third, enhanced counter value capability is also a possible measure for cost imposition. There are few targets of value in North Korea. It has no many big cities like Seoul or industrial complexes like South Korea has. Furthermore, counter value targeting has limitations due to humanitarian considerations. However, there is an available counter value target, which is precious to the regime—its political leadership including Kim Jung-un.  

“Counter Political Leadership Targeting” is possible. If South Korean intelligence had a list of the North’s political elite, the location of their shelters and the capability to strike them,²⁶ North Korea would face with hardship from South Korea’s retaliation capability.²⁷ To respond to South Korean counter political leadership capability, North Korea would have to pay more to have additional hardened shelters, enhanced counter special operation capabilities, and a defense system to protect its political leadership.

During the Cold War, the United States used advanced technology such as SDI for cost imposition on the Soviet Union. Recent advanced military technology also allows for imposing a great deal of cost on an adversary even if a nuclear weapon is not used. Advanced drone warfare and jamming technology can be used for cost imposition.

Recommendations

Despite many challenges, the ROK-US alliance should achieve North Korean denuclearization based on mutual trust and cooperation. It should build a more reliable and stronger deterrence architecture not only to respond to each North Korean provocation, but to frustrate every military ambition North Korea might pursue. Additionally, the architecture should be designed to impose heavy costs on North Korea. For this purpose, the two countries should have a shared perspective on the main issues related to North Korean nuclear strategy and deterrence. It would be highly difficult to come to agreement on many issues, but at least it is possible to exclude the extreme arguments not based on reliable evidence and sound theoretic tests, and to keep balance not to be inclined to the wrong positions founded on unproven arguments. It is very important especially for reassuring the South Korean people.

Until the alliance finally succeeds in denuclearizing North Korea, reassurance to South Koreans is one of the most important things to do. To do this, prominent experts from the two countries should gather to discuss the main points related to building the deterrence architecture. They should provide reliable and authoritative information on which others can shape their understanding of the current situations and their opinions on how to deal with the North Korean threat. By gaining confidence that we will win the race even without fighting, we can finally achieve denuclearization of North Korea and a peaceful Korean Peninsula.