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  • Flawed Assumption in Pro-Nuclear Arguments and South Korea's Strategic Choice

In this article I explore assumptions behind the aspiration for nuclear armament in South Korea. An increasing number of South Koreans advocate nuclear armament of their country, either by redeploying US tactical nuclear weapons or by developing an indigenous nuclear capability. Support for "going nuclear" reflects three beliefs: nuclear weapons can serve as a shield from external bullying, the balance of power between Seoul and Pyongyang has shifted due to Pyongyang's growing nuclear capability, and possessing nuclear weapons is the sole way to protect ROK national interests given growing skepticism over the credibility of the US nuclear umbrella. I revisit deterrence theory to demonstrate that these perceptions are based on the flawed assumption that nuclear weapons can only be deterred by other nuclear weapons. This assumption—an extrapolation from the Cold War experience—does not consider technological breakthroughs made since then. In fact, modern, technologically advanced conventional weapons can also deter nuclear weapons, especially those using relatively underdeveloped technologies. By continuously modernizing its conventional weapons and strengthening the ROK-US alliance, South Korea can deter Pyongyang from contemplating a nuclear assault on South Korea.


South Korea, nuclear weapons, ROK-US alliance, North Korea

As the tension between the two Koreas has intensified, an increasing number of South Korean people support the idea that the Republic of Korea (ROK or South Korea) should "go nuclear." According to a poll conducted in 2013, 67 percent of respondents favored South Korea's acquisition of nuclear weapons, while only 28.8 percent opposed (Chung Min-uck 2013a). The percentage has been quite consistent: a 2016 poll [End Page 123] revealed that 67.7 percent favored the nuclear option, whereas 30.5 percent opposed (Park 2016). Other polls show that the proportion harboring the idea of nuclear-equipped South Korea varies from as little as 58 percent (Yonhap News Agency 2016a) to as much as 68.2 percent (Korea Society Opinion Institute 2017). However, it appears that those favoring nuclear armament, through either redeployment of US tactical nuclear weapons or indigenous development, are always greater in number than those opposing it. In addition, many leading conservative figures, including Chung Mong-joon, a seven-term National Assembly member, Won Yoo-Chul, a five-term National Assembly member, and Kim Moo-sung, a six-term National Assembly member, advocate that South Korea should "go nuclear" (Chung Min-uck 2013b; Park 2016). Recently, Hong Jun-pyo, a former chairperson of the largest South Korean opposition party, the Liberty Korea Party, publicly argued that South Korea should consider withdrawing from the Nuclear Non-Proliferation Treaty (NPT) to build nuclear weapons (Yonhap News Agency 2017b). Given that all of these individuals are political heavyweights, their remarks and ideas carry weight in the foreign policy decisionmaking process in Seoul. Moreover, conservative media outlets, such as Chosun Ilbo, the newspaper with the largest daily circulation in South Korea, also support this idea. Kim Dae-joong, a former chief editor and a current senior advisor of Chosun Ilbo, asserts that South Korea is entitled to withdraw from the NPT according to Article X and must announce development of a nuclear arsenal to guarantee its survival (Kim Dae-joong 2016). Other chief editors and scholars often repeat similar arguments (Cho 2011a; Cheon 2017).

Given the growing aspirations for nuclear weapons in South Korea, in this article I attempt to answer the following questions: Why do South Koreans endorse nuclear armament? What assumptions are shared by nuclear weapon advocates? Can a nuclear strike from the Democratic People's Republic of Korea (DPRK or North Korea) only be deterred by other nuclear weapons? And ultimately, should South Korea go nuclear? The next section explores three major reasons why many people in South Korea endorse nuclear armament. It argues that nuclear advocates, although well aware of possible adverse consequences of such a choice, believe that South Korea can protect its national interests only through a nuclear weapons buildup. They also argue that while the balance of power between South Korea and North Korea has been altered with Pyongyang's nuclear development, the credibility of the US nuclear umbrella extended to South Korea is questionable. Hence, they are convinced that possessing a nuclear arsenal is the only way to guarantee [End Page 124] South Korea's security. The following section questions the assumption that nuclear weapons are so unrivaled that they can be deterred only by nuclear weapons. To the contrary, I argue that this assumption is a legacy of the Cold War and that advanced conventional weapons can deter nuclear strikes. After exploring Pyongyang's nuclear capabilities and the ROK-US conventional capabilities, I argue that South Korea, with US support, possesses sufficient military capabilities to deter a nuclear assault by Pyongyang.

Pro-Nuclear Arguments in South Korea

In general, aspirations for nuclear weapons in South Korea stem from three perceptions: nuclear weapons can serve as a shield from external bullying, the balance of power between Seoul and Pyongyang has shifted in favor of North Korea due to Pyongyang's growing nuclear capability, and the credibility of the US nuclear umbrella is increasingly questionable. As a result, advocates argue that possessing nuclear weapons is the sole way to protect ROK national interests.

A Shield Protecting a Shrimp from the Fighting of Whales

According to an old Korean saying, "When caught up in a whales' fight, a shrimp has his back broken." This proverb has often been used to depict Korea's situation—stuck in the middle of great power rivalry. Korea experienced major setbacks in its history when there was a power shift among surrounding countries: the Japanese invasions from 1592 to 1598 when power in Northeast Asia shifted from the Chinese Ming dynasty to Toyotomi-led Japan; the Jin (later Qing) invasions in 1627 and 1636 when a hegemonic state in China shifted from the Ming dynasty to the Jin (Qing) dynasty; the First Sino-Japanese War from 1894 to 1895 when the Qing dynasty declined and the Japanese Empire rose; the Russo-Japanese War from 1904 to 1905 when the Russian Empire and the Japanese Empire fought in Korea; and the Korean War (1950–1953) when the communist and capitalist camps competed. Recollections of these historical events lie at the root of South Korean aspirations for nuclear weapons: they view nuclear weapons as a shield protecting South Korea from being bullied by external powers and preventing its back from being broken. [End Page 125]

South Korea's nuclear aspiration is more than forty years old. After witnessing the US failure to support the Saigon government when North Vietnam began its final offensive in 1975, despite the "swift and severe retaliatory action" promised by Richard Nixon (Nixon 1985, 155–156; Kissinger 2003, 385), Seoul became concerned about its security. This resulted in President Park Chung-hee's clandestine nuclear weapons program (Oberdorfer and Carlin 1999; Hayes and Moon 2011). In exchange for shutting down the program, Washington formally documented the provision of the nuclear umbrella over South Korea for the first time during the Eleventh Korea–United States Security Consultative Meeting in 1978 (Kim 2012, 75). President Chun Doo-hwan, Park's successor, also expressed his desire to possess nuclear weapons by saying, "As the U.S.-Soviet Union talks go well if the U.S. develops the SDI, the principle is the same that if we have just three nuclear weapons, the North would respond to calls for inter-Korean talks" (Yonhap News Agency 2017a).

This long-standing aspiration for a nuclear shield has gained salience again in recent years. Viewing China's rise and the relative decline of the United States, many people have conjured up historical setbacks and concerns about South Korea "having its back burst." Kim Dae-joong, a former chief editor and a current senior advisor of Chosun Ilbo, argued that "probably the U.S. will regard nuclear North Korea as a substantial threat only when Pyongyang succeeds in developing ICBM. It is obvious that [the United States], until then, will exercise absolute control over nuclear development of small countries such as South Korea, under the pretext of nuclear nonproliferation. … When it comes to China, [we] have been through enough already. [South Korea] would rather surrender to North Korea than to trust China to save Korean nation." Therefore, nuclear armament, for supporters, is the sole guarantor of South Korea's national security in an international society where all countries follow only their own interests. "With regard to the nuclear issue, no one is reliable," Kim added (Kim Dae-joong 2016).

Equalizer of Power Imbalance

Another factor behind South Korean people's aspiration for nuclear weapons is that the power balance between South and North Korea is shifting in favor of Pyongyang, as Pyongyang developed nuclear capabilities. Therefore, nuclear-weapon advocates are convinced that only through possession of their own nuclear capabilities can Seoul correct [End Page 126] this asymmetric balance of power and guarantee a deterrent against nuclear strikes from North Korea. For example, in explaining why South Korea should go nuclear, Chung Mong-joon described the security situation of the Korean peninsula by saying that South Korea is struggling to defend itself with a pebble in front of "a gangster in the neighborhood buying a brand-new machine gun" (Herman 2013). In other words, for many South Koreans, indigenous nuclear weapons would equalize the power imbalance between the two Koreas.

This perception can be found in many commentaries of nuclear advocates in South Korea. For instance, a former chief editor of Chosun Ilbo asserts that "the day when the North Korean regime will threaten South Korea's survival by deploying long-range missiles tipped with miniaturized nuclear warheads is approaching. … It is highly doubtable whether [South Korean] leadership [without nuclear weapons] can make a decision to fight back, when [nuclear-armed] North Korea, after invading South Korea and besieging Seoul, proposes an armistice treaty in the current position and warns it will use nuclear weapons if the South Korean government rejects" (Cho 2011b). Conservative politicians echoed these sentiments. Hong Jun-pyo, a former leader of the largest conservative party, claimed that "it is time to save [our] country through nuclear balance" (Yonhap News Agency 2017c) and that "peace will come when we achieve a balance of power, not when we are begging for it" (Yonhap News Agency 2017d). Even some liberal politicians agreed with this idea. Kim Jin-pyo, a four-term lawmaker of a ruling liberal party, said, "The situation has changed [with Pyongyang's possession of nuclear weapons]. … We should seek all possible means to better defend ourselves from the North," adding that "the redeployment of U.S. tactical nuclear weapons can be a certain tit-for-tat measure" (Kim Hyo-jin 2016). While many pro-nuclear advocates prefer redeployment of US tactical nuclear weapons (TNW) in South Korea, developing indigenous nuclear weapons is an alternative given that the United States is unlikely to agree to redeployment. In fact, the largest opposition party recently organized a "nuclear forum" within the party, sent a letter to Donald Trump with 74 signatories out of 105 members, and dispatched a group to Washington to request TNW redeployment (Cheng 2017). After Washington's reluctant response, they suggested that South Korea consider nuclear armament and withdrawal from the NPT (Yonhap News Agency 2017b). "If the U.S. does not deploy tactical nuclear weapons [in South Korea], [Seoul] can have sound reasons to [pursue] nuclear armament independently," argued the opposition party leader (Yonhap News Agency 2017c). [End Page 127]

For nuclear armament advocates, nuclear weapons can also serve as a bargaining chip to compel Beijing to pressure Pyongyang. Convinced that China is capable of, but not willing to, putting pressure on North Korea, they argue that China's self-centered policy toward North Korea undermines South Korea's national security. Thus, South Korea's nuclear development, they assert, would result in China's active role in pressuring North Korea, out of fear of a nuclear domino effect—especially Japanese nuclear armament.

Pro-nuclear politicians and opinion leaders are well aware of the potential economic damage that homegrown nuclear weapons could have on South Korea: possible bilateral and multilateral sanctions, suspension of nuclear technology transfer, and disruption in nuclear fuel supply. Nevertheless, they emphasize that Pyongyang's nuclear weapons development is a direct challenge to South Korea's survival. Therefore, Seoul must counterbalance by any means, regardless of any possible disadvantage. To them, the sole way to do so is by equipping South Korea with nuclear weapons. A conservative politician argued, "It is absurd to give up the lives of 50 million South Koreans due to the fear of economic sanctions" (Yonhap News Agency 2017c). Supporters of a nuclear South Korea perceive that, with Pyongyang possessing nuclear weapons, the balance of power between the two Koreas shifted in favor of North Korea and that the situation can be fixed only by South Korea's nuclear armament, either through redeployment of US tactical nuclear weapons or through developing indigenous ones.

Torn US Nuclear Umbrella

One may counter that South Korea, even though threatened by Pyongyang, can rely on the US nuclear umbrella. "Seoul needs a counter to that [North Korea's nuclear] threat. … At this point in time, it makes good strategic sense for South Korea to rely on America's nuclear umbrella," said renowned American political scientist and international relations scholar John Mearsheimer (Joongang Daily 2013). Since its initial explicit declaration in 1978, the United States has reaffirmed its commitment to providing its nuclear umbrella to South Korea on several occasions, especially after North Korea's first nuclear test on October 9, 2006. Days after the first nuclear test, Donald H. Rumsfeld, then US secretary of defense, "offered assurances of firm U.S. commitment and immediate support to the ROK, including continuation of the extended deterrence offered by the U.S. nuclear umbrella" during the Korea–United [End Page 128] States Security Consultative Meeting in Washington, D.C., on October 20, 2006 (38th Security Consultative Meeting Joint Communiqué 2006). In June 2009, a month after North Korea's second nuclear test, the presidents of South Korea and the United States adopted a "Joint Vision for the Alliance" that emphasized the role of extended deterrence, including the nuclear umbrella, in coping with North Korea—the first time for such at the presidential level. In October 2010, the two countries agreed to establish the Extended Deterrence Policy Committee to enhance the effectiveness of extended deterrence. The committee was combined with the Counter Missile Capability Committee to become the Deterrence Strategy Committee in 2015, before it finally developed into today's Extended Deterrence Strategy and Consultation Group (Ministry of National Defense, Republic of Korea 2010; Yonhap News Agency 2016b). During this process, the provision of the US nuclear umbrella over South Korea has been reiterated several times at both the presidential and the ministerial levels.

Nevertheless, those who support nuclear armament are skeptical of the US assurances. A North Korean preemptive nuclear strike against the United States would cause a furor among US citizens, which will significantly lower the nuclear threshold. A ruthless response from Washington appears guaranteed in such a case. Yet, nuclear retaliation in the event an ally is attacked and risking one's involvement in a war is a harder decision. As a former senior Pentagon official said, "The problem of extended [nuclear] deterrence is simply the international and political problem of credibility of retaliation with potentially suicidal consequences against serious, but not inevitably fatal, threats" (Slocombe 1984, 94). So, the skeptics argue, no matter how strong the US rhetorical commitments to protect its allies, these commitments cannot be as strong as the will to protect its homeland. "The difference between national homeland and everything 'abroad' is the difference between threats that are inherently credible, even if unspoken, and the threats that have to be made credible" (Schelling 1966, 36). The credibility of extended deterrence has been problematic to many South Koreans since the United States first guaranteed it to South Korea, but it became even more troublesome as Pyongyang claims to possess the capability to respond to "the U.S. hostile policy" with a nuclear-tipped intercontinental ballistic missile (Cohen and Starr 2017). The doubt is no longer whether Washington is willing to accept the risk of being involved in war and sacrificing lives of deployed troops, but whether the United States will risk its major cities and millions of citizens to protect South Korea. Recalling the same concern among the US's European allies during the [End Page 129] Cold War, some skeptics in South Korea support the so-called NATO Model of nuclear sharing: just as Washington has been deploying B61 nuclear bombs in five NATO member states—Belgium, Germany, Italy, the Netherlands, and Turkey—they argue that the United States should deploy nuclear bombs in South Korea. According to them, the United States may keep possession of those weapons as in the case of NATO, but South Korea should have a voice in strategic planning for and the use of the weapons, by providing means of loading and delivery such as the F-15K Slam Eagle or F-35 Lightning II (Yoon 2016). They believe such visible measures will have positive psychological effects in assuaging security concerns among South Koreans, while they would have the symbolic effect of demonstrating US alliance commitment. They also assert that since Pyongyang's nuclear strike against US nuclear weapons deployed in South Korea would ensure nuclear retaliation of Washington, the weapons would enhance the credibility of the US nuclear umbrella as well (Cheon 2017).

Skeptics also argue that the credibility of the US nuclear umbrella appears even more untenable due to a "nuclear taboo" in the United States. They argue that due to its enormously destructive nature, the US public views nuclear attacks as "severely delegitimized and are practically unthinkable policy options," and that this sense of revulsion has made the use of nuclear weapons de facto prohibited (Tannenwald 2005, 5). Although the nuclear taboo can be found throughout the world, the use of the nuclear arsenal is particularly abhorrent in the United States, in that the United States was the first developer of the technology and is the only country that has any experience using it in war. Such widespread aversion to the use of nuclear weapons, no matter whether as a first strike or for reprisal, significantly affects US decisionmakers. With opposition parties always ready to take advantage of unpopular decisions, US decisionmakers, who need to be concerned with constituents' views to remain in office, will find it extremely hard to cross the nuclear threshold. Skeptics believe that this revulsion to nuclear weapons circumscribes US decisionmakers' options and makes the use of nuclear weapons highly unlikely.

For skeptics, the Barack Obama administration's initiative for a Nuclear-Free World was another serious event, demonstrating the "incredibility" of the US nuclear umbrella. Unlike the George W. Bush administration, which, according to the 2002 Nuclear Posture Review (NPR), had drawn up contingency plans to use nuclear weapons against potential target states including North Korea, the Obama administration attempted to reduce not only the size but also the role of nuclear forces, [End Page 130] envisioning the global elimination of nuclear weapons. In a speech delivered on April 5, 2009, the day that North Korea launched another long-range rocket, President Obama outlined his vision of a world without nuclear weapons. He said that "the existence of thousands of nuclear weapons is the most dangerous legacy of the Cold War" and pledged to reduce the US nuclear stockpile. Although he qualified his statement by noting that "North Korea must know that the path to security and respect will never come through threats and illegal weapons" (BBC 2009), the speech seriously undermined the credibility of the US commitment to nuclear protection for South Korea. Furthermore, the Obama administration's 2010 NPR substantially narrowed the conditions under which the United States would consider using nuclear weapons. In particular, the review for the first time ruled out an option to retaliate with nuclear weapons against aggression against the United States involving biological, chemical, or conventional weapons, as long as they are in compliance with the NPT (BBC 2010). With regard to the US deterrence policy, including extended deterrence and security assurances to its allies and partners, the 2010 NPR stipulates that because the security environment has changed since the end of the Cold War, the United States would also need to change its extended deterrence policy by reducing the role of nuclear weapons, while depending more on its conventional arsenal and missile defense system (Department of Defense 2010). Since North Korea does not consider itself to be a member state of the NPT, it can be argued that it is excluded from the 2010 NPR's nonuse nuclear rule. Moreover, Obama's successor Donald Trump has been confronting Pyongyang with "verbal bombs." Nevertheless, the volte-face in US nuclear policy during Obama's term gave skeptics sufficient reason to doubt the credibility of the US commitment. As a result, the nuclear armament supporters in South Korea assert that the US nuclear umbrella is "torn," preferring more tangible solutions that they believe are redeployment of US tactical nuclear weapons or development of an indigenous nuclear arsenal (Yang 2015).

Flawed Assumptions and Reality on the Korean Peninsula

As shown in the previous section, a considerable number of South Koreans fear that Pyongyang's nuclear weapons create an asymmetric balance of power between the two Koreas. They also believe that South Korea may be "abandoned" by Washington (Snyder 1984), as the [End Page 131] United States becomes increasingly vulnerable as North Korea comes closer to having an operational intercontinental ballistic missile. Some South Koreans also believe that the United States is capricious enough to change its alliance commitment whenever needed. As a result, many are convinced that South Korea must counterbalance these uncertainties through nuclear armament, an argument that is prevalent in both academic and policy communities (Waltz 1981; Jervis 1989; Van Evera 1999; Mearsheimer 2001). An editorial in South Korea read, "It is time to discuss nuclear armament in terms of 'the balance of terror'—'a nuke for a nuke.' [South] Korea is sufficiently qualified for that matter" (Harris 2017).

Yet, I argue that there are alternatives that must be explored. South Korea can deter Pyongyang's nuclear attacks without nuclear weapons, by strengthening its alliance with the United States and by advancing its conventional military capabilities. First, even though Pyongyang's nuclear capabilities are improving rapidly, they are not as destructive as generally believed. Second, according to deterrence theory, conventional weapons can also deter nuclear weapons if they can inflict unacceptable damage on attackers with second strikes.

Nuclear Capability of North Korea

Given the opacity of Pyongyang's nuclear program, the exact nuclear capability of North Korea is difficult to estimate. However, according to a computer simulation, the nuclear devices tested by Pyongyang, despite its rhetoric, are not capable of "turning Seoul into a Sea of Fire." Specifically, the first atomic device tested by Pyongyang was equivalent to less than 1 kiloton of TNT (trinitrotoluene). The second and third tests were equivalent to 2 kilotons and 8 kilotons of TNT, respectively. The fourth test in January 2016, which Pyongyang claimed to be a hydrogen bomb but was disputed by experts based on the total energy released, was less powerful than the third test, with an equivalent of 6 kilotons of TNT (Keller, Fessenden, and Wallace 2016). The fifth test was known to be equivalent to 10 kilotons of TNT (Hunt, Kwon, and Hanna 2016). Thus far, the most advanced and powerful nuclear device tested by Pyongyang is the sixth, tested in September 2017. Estimates of its yield range from 50 kilotons of TNT to 280 kilotons (Lee 2017). While a significant advance, it would not annihilate South Korea. In a computer simulation, a bomb with a yield of 280 kilotons of TNT would be expected to cause 763,030 deaths and 3,039,290 injuries when dropped on Yongsan [End Page 132] in Seoul, the most densely populated part of South Korea and where the ROK-US Combined Forces Command is located. The estimated casualties account for approximately 7.4 percent of South Korea's population. More than 90 percent of South Korean people would survive unhurt. The fireball radius of a 280 kiloton bomb, the most direct impact, is expected to cover 1.06 square kilometers, while the thermal radiation radius, a relatively indirect impact that would cause third-degree burns, is expected to cover 165 square kilometers.1 A large part of Seoul, which is as large as 605.21 square kilometers, would remain intact even after the worst nuclear strike imaginable. In the worst-case scenario, Pyongyang may employ nuclear and conventional weapons simultaneously. Pyongyang's conventional artillery barrage can cause 30,000 casualties in Seoul if the barrage focuses on counter-value targets. When it targets South Korea's military forces, by contrast, initial casualties are expected to be ten times less than against counter-value targets, and the casualty rate would quickly decline as the surprise wears off (Cavazos 2012). Again, while truly horrible, even under this worst-thinkable scenario, a nuclear strike by North Korea would likely not reduce the ROK-US alliance's retaliation capability to an "acceptable" level. In other words, South Korea, albeit seriously damaged, would be expected to retain sufficient strike-back capability.2

This is not to trivialize the destruction that may be caused by a North Korean nuclear assault, nor does it mean that Pyongyang's nuclear strike is not dangerous. In fact, North Korea's nuclear capability is rapidly improving. Nevertheless, its nuclear weapons, at least as of now, are not destructive enough to eliminate the retaliatory capability of the ROK-US alliance. Pyongyang would expect the alliance to retaliate if it initiated war with nuclear weapons. Then, what would be the degree of retaliation? Can retaliation with residual forces inflict "unacceptable" punitive damage on Pyongyang?

Deterrence Theory Revisited

Deterrence theory postulates that a potential attack by an attacker can be deterred when the attacker does not have capability to destroy enough of a deterrer's force to reduce its retaliation to an "acceptable" level by a counterforce "first strike," or to maintain a sufficient force to pose grave menace to make the deterrer concede due to the threat of massive damage to cities or population (Snyder 1961, 35; Snyder 1965, 187–188; George and Smoke 1974, 11). Put simply, deterrence can be [End Page 133] achieved when a deterrer, after suffering the potential attacker's first blow, still possess "residual retaliation capability," which is sufficient to inflict "unacceptable" damage on the attacker. Hence, the theory does not mention a specific means of reprisal. If a deterrer, after a first strike, still has residual capability to inflict "unacceptable damage" on an attacker, regardless of whether it is conventional or nuclear, deterrence can be sustained.

Since there was no means except for nuclear weapons to inflict "unacceptable" damage during the Cold War when the theory was first introduced, it was assumed that a nuclear arsenal was the sole guarantor of stability in the nuclear age. Indeed, "[the concept of] deterrence became virtually synonymous with nuclear weapons" (Guertner 1993, 141). However, the view, which was extrapolated from the experience of the Cold War, has been challenged recently, especially after the Gulf War (1990–1991), given remarkable advances in conventional weapon capabilities. The Gulf War served as a "spectacular demonstration of the potential effectiveness of smart weapons used in strategic role" (Nitze 1994). Scholars now claim that modern, technologically advanced conventional weapons can assume many missions previously assigned to nuclear weapons (Perry 1991; Allan 1994; Cropsey 1994; Gerson 2009). In other words, a potential North Korean nuclear strike can be deterred if South Korea, after Pyongyang's preemptive strike, maintains residual forces that can inflict "unacceptable" damage through a retaliatory attack, regardless of the type of weapon used.

Since the concept of "unacceptability" is by its nature subjective, it ultimately depends on the value Pyongyang places on its capitulation to Seoul's demands. Scholars widely believe that leaders of authoritarian states, such as North Korea, care less about sacrificing the lives of their citizens (Cropsey 1994, 15). Recent studies of declassified documents revealed that the leaders of Imperial Japan did not much feel pressure to capitulate even after the massive casualties in the Hiroshima bombing; the bombing was not the principal factor that compelled the leadership to surrender (Wilson 2007). Likewise, "counter-value targeting" may not be an effective way to inflict "unacceptable" damage on leaders in Pyongyang (Ball and Richelson 1986). Moreover, a massive counter-value attack may invite further risk, since it can make North Korean leaders lose control and become irrational. Instead, what is most threatening to dictatorial states such as North Korea is the destruction of military capabilities, which provide a material guarantor of its regime. Compounds for leadership, command and control assets, nuclear facilities, and underground bunkers can be included in this category. In other [End Page 134] words, what is needed to deter North Korea is not an extensive second-strike capability, which could devastate North Korea, but a "moderate counterforce strike-back capability" that would be sufficient to disarm Pyongyang to the point of threatening the stability of the regime.

Conventional Weapons Deterring Nuclear Weapons

In this context, conventional weapons can be more effective in inflicting unacceptable damage on Pyongyang. First, in contrast to counter-value targets that are largely sedentary, North Korea's leadership and its forces are highly mobile. This means that attacking them requires precise targeting technologies and combat flexibility, which can be better achieved with advanced conventional weapons rather than nuclear bombs (Morgan 2003, 276). Second, conventional attacks cause less collateral damage and are less politically and morally constrained; there is no such thing as "conventional taboo." Moreover, public fury over Pyongyang's preemptive nuclear strike will be sufficient to overwhelm remaining constraints on conventional retaliation. In other words, conventional deterrence is a lot more credible than nuclear deterrence.

Three major technological breakthroughs in conventional weapons since the Cold War enable them to serve as an alternative to nuclear weapons in deterring Pyongyang. First, intelligence technologies have advanced since the end of the Cold War. Allegedly, North Korea's major strategic weapons, especially its nuclear forces, are concealed or mobile. Such measures may have ensured the weapons' survivability during the Cold War era. Yet, "in the ongoing competition between 'hiders' and 'seekers,' … the hider's job is growing more difficult than ever before" (Lieber and Press 2017, 32). During the Cold War, photoreconnaissance from satellites or aircraft, wiretapping, and human intelligence were major means of collecting enemy information. Nowadays, technologies in these fields are much more sophisticated and are supplemented by other new sensor platforms such as remotely piloted aircraft and underwater drones. These breakthroughs provide high-resolution photoreconnaissance, real-time tracking of enemy's forces, and nearly real-time data transmission. Research has found that US satellites equipped with synthetic aperture radars, when supplemented by other surveillance system, can monitor virtually all roads in North Korea and identify all targets (Lieber and Press 2017). In other words, intelligence technologies have advanced to a point where they negate Pyongyang's concealment or mobility [End Page 135] strategies for its forces. Having signed the ROK-US bilateral intelligence cooperation agreement in 1987 and the ROK-US-Japan trilateral intelligence-sharing pact in 2014, and ROK-Japan bilateral General Security of Military Information Agreement in 2016, Seoul can enjoy the fruits of these technological advancements. South Korea should consider reinforcing its intelligence capabilities, although they are not yet perfect, before going nuclear.

Second, the destructive power of conventional missiles and bombs has improved markedly since the Cold War. They cannot yet match nuclear weapons, but they are formidable enough to render an enemy's hard and deeply buried targets vulnerable. For example, the GBU-57A/B Massive Ordnance Penetrator, a massive precision-guided 30,000-pound bunker-buster bomb, can destroy targets buried as deeply as 200 feet (60.9 meters) (Lindeman and Webster 2012). Since 2014, South Korea has deployed 150 GBU-28 bunker busters imported from the United States, which are always ready to be loaded to and dropped from an F-15K (Joongang Daily 2014). In addition, Seoul recently also successfully tested indigenous bunker-busting ballistic missiles, the Hyunmoo-II missile system (Lockie 2017). Moreover, after Seoul reached agreement with Washington to scrap restrictions on South Korea's warhead weight in September 2017 (Reuters 2017), South Korea is reportedly developing more sophisticated and powerful ballistic missiles with a 2-ton warhead, which will be able to destroy North Korea's underground bunkers buried as deep as 20 to 30 meters (Yoo and Lee 2017). Even under the worst-case scenario in which all of South Korea's missile and bomber capabilities are eliminated as a result of Pyongyang's nuclear first strike (highly unlikely given that they are scattered throughout South Korea), a GBU-57A/B dropped from a US B-2 stealth bomber can destroy virtually all hard and deeply buried targets in North Korea. Given that the North Korean air defense system is outdated, if not obsolete, Pyongyang is likely to be unable to detect, let alone shoot down, US stealth aircraft including the F-22 Raptor, F-35 Lightning II, and B-2. Pyongyang reportedly failed to detect US bombers several times already, allegedly due to a lack of power to operate radar around the clock (Yeo 2017). In 2014, Seoul also decided to enhance its air combat power by signing a contract to purchase forty F-35A Lightning II fighters and is considering procuring twenty more (Gady 2016). Equipped with strong bunker-busting bombs, the fighters, which are scheduled to be delivered in 2018, will guarantee Seoul a strong counterforce strike-back capability. [End Page 136]

Third, the accuracy of conventional weapons has meanwhile been upgraded too. During the Cold War, neither bombers nor ballistic missiles could ensure accurate destruction of an enemy's strategic targets. Variables such as an aircraft's speed and altitude and atmospheric conditions impeded the accuracy of targeting by bombers and ballistic missiles (Rip and Hasik 2002). However, technological leaps in navigation and guidance led to precision-guided munitions. Today, missiles and bombs, equipped with onboard GPS (Global Positioning System) computers, are "smart" enough to locate their precise position and adjust trajectory while on course to destroy designated targets. In addition, mobile delivery systems can also determine their location precisely prior to launch, greatly enhancing munition accuracy. This increased accuracy, when combined with increased destructive power, enables conventional weapons to substitute for the deterrence mission previously assigned to nuclear weapons. South Korea now also enjoys technological leaps in munition accuracy. Not only is it using US-made smart bombs such as the Joint Direct Attack Munition and GBU-28, the Agency for Defense Development has been producing the Korea GPS Guided Bomb (KGGB) since 2012. Supported by US military GPS technology to prevent signal jamming by Pyongyang, the Agency for Defense Development has announced it will deploy 1,200 KGGBs by 2018 (Chung 2017).

While people highly value the destructive power of nuclear weapons, they fail to appreciate the conventional weapon capability of the ROK-US alliance. In fact, there exists a significant imbalance between the two Koreas, with South Korea being far superior in terms of conventional power (O'Hanlon 1998; Hamm 1999; Suh 2004; Hayes and Moon 2015). As of 2017, South Korea is the 12th strongest state among 133 countries with a $43.8 billion annual defense budget, whereas North Korea ranks 23th with a budget of $7.5 billion (Global Firepower 2017). South Korea is spending almost six times more than North Korea on defense. As a result, the ROK conventional military power, with augmentation from US forces, is far superior to that of the DPRK. The imbalance is large enough to ensure that the ROK-US alliance retains sufficient conventional capability to inflict "unacceptable" damage on the Pyongyang regime, even after a nuclear first strike. In other words, Pyongyang's nuclear attack can be deterred because of the asymmetry in conventional military strength. Thanks to such conventional superiority, the ROK-US alliance can deter a nuclear assault from Pyongyang, even without redeploying US tactical nuclear weapons or developing an indigenous nuclear capability. [End Page 137]


In this article I examined the rationales of nuclear weapon advocates in South Korea. By arguing that the introduction of nuclear weapons will prevent South Korea from being bullied by external powers, that the balance of power between the two Koreas has been skewed in favor of North Korea, and that the US nuclear umbrella lacks credibility, advocates seem convinced there are no less costly alternatives. This argument is based on the false assumption that "nuclear can only be deterred by nuclear," however. In fact, this assumption is mistakenly extrapolated from the Cold War experience. Nowadays, technologically advanced conventional weapons can also deter nuclear attacks. Thus, Seoul can first rely on reinforcing its conventional forces and strengthening its alliance with the United States before making a decision to "go nuclear." Seoul can consider modernizing its surveillance capabilities and sophisticated conventional bunker-buster technologies, procuring more stealth fighters, reinforcing missile/bomb accuracy and destructive power, and strengthening intelligence sharing with the United States.

Nuclear options for South Korea are either infeasible or too costly. Given that the United States has been minimizing the salience of its nuclear arsenal in its strategic planning and relations with its allies, it is highly unlikely that Washington would agree to redeploy tactical nuclear weapons to the Korean peninsula. Washington already dismissed this option when requested to do so by South Korean opposition party leaders. By contrast, indigenously developed nuclear weapons, albeit technologically possible, will only diminish South Korea's standing in the nonproliferation community, and intensify inter-Korean psychological warfare with no substantial gain in deterrence impact. They could also jeopardize the ROK-US alliance, initiate a "nuclear domino" effect in Northeast Asia, and exacerbate the security dilemma in the region.

Since Pyongyang is highly likely to further modernize its nuclear arsenals, voices calling for nuclear armament will continue to resonate in South Korea. However, at least currently and for the foreseeable future, it is more advantageous for South Korea to develop conventional weapons and strengthen the ROK-US alliance. Pyongyang's nuclear threat is formidable, but it is not as formidable as the conventional military strength of the ROK-US alliance. [End Page 138]


Daekwon Son is a PhD candidate in International Relations at Peking University and a Kim Jun-Yop Fellow of the Institute of Social Sciences. He is a former Korea Foundation Resident Fellow at the Pacific Forum CSIS (2017) in Honolulu, USA. His research interests include Sino-US relations, ROK-US alliance, North Korea's nuclear armament, and China's nuclear posture, among other research topics. He has published multiple peer-reviewed journal articles and op-eds in Korean, English, and Chinese. He can be reached at

The author would like to thank Wang Dong, Mei Ran, Peter Hayes, Chung-in Moon, Jaewoo Choo, Yang Xiangfeng, and Jung Nam Lee for their support and comments on the earlier draft of this article. He also gratefully acknowledges the support of the Korea Foundation fellowship at Pacific Forum, where Carl Baker, Ralph Cossa, Brad Glosserman, and David Santoro were especially helpful.

1. The simulation is predicated on the assumption that North Korea's bomb is air burst to maximize damage to South Korea. If the bomb bursts on the surface, the damage is expected to be smaller. A computer simulation of a nuclear bomb can be conducted at For details about calculating casualties, refer to

2. Attacking proximate targets in a short time frame with multiple nuclear war-heads causes one warhead to destroy others, unless an attacker can guarantee high missile or bombing accuracy. This "nuclear fratricide" problem will force Pyongyang to disperse targets when launching multiple nuclear preemptive strikes simultaneously. Since Seoul is the most densely populated city in South Korea and many mountainous areas are far less populous, the damage inflicted by simultaneous nuclear attacks will be a lot smaller than simple multiplication of the putative damage on Seoul. For example, if the attack is on Gyeryong-si, where South Korea's military headquarters are located, total casualties are estimated to be 65,330.


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