KEY TAKEAWAYS
KEY TAKEAWAYS
On President Donald Trump’s first day in office, he referred to North Korea as a “nuclear power.” Just a few months before, North Korean dictator Kim Jong Un said he would “exponentially” increase his country’s nuclear weapons arsenal, which he followed by testing a new intercontinental ballistic missile and a new hypersonic missile. Additionally, there are concerns that Moscow may transfer sensitive military technologies to North Korea in exchange for Pyongyang supplying weaponry and troops for Russia’s war on Ukraine. These developments inject new urgency into a key question that will have major ramifications for stability and security on the Korean Peninsula and beyond: Should South Korea go nuclear?
However, there are significant risks that make the idea of a nuclear South Korea premature at best. North Korea may be more likely to consider strikes against South Korea to maintain its nuclear advantage. Also, although a nuclear-armed South Korea would likely deter a North Korean nuclear attack, it could also significantly heighten the risk of a conventional conflict, which could drag the United States, South Korea’s treaty ally, into a war.
This risk is particularly pronounced in light of impeached President Yoon Suk Yeol’s reckless North Korea policy, which allegedly intended to provoke Pyongyang into a military clash to justify his declaration of martial law. While Yoon is likely to be removed from office, South Korea’s democracy appears to be in serious jeopardy. The country’s first priority should be to restore confidence in South Korea’s democracy and rule of law.
Despite the Yoon government’s reaffirmation of South Korea’s long-standing nonproliferation commitment in the April 2023 Washington Declaration, the nuclear armament debate persists. Public opinion polls consistently indicate that a majority of South Koreans support nuclear armament. Recently, South Korean elites, including prominent lawmakers, reignited this call given the intractability of North Korea’s nuclear weapons. The rationale is that Seoul should pursue nuclearization to counter North Korea’s escalating nuclear threats and to prepare for any future uncertainties in the U.S.-South Korea relationship.
South Korea’s desire for nuclear weapons is not hard to understand given its security concerns, but nuclearization would not necessarily lead to greater stability on the Korean Peninsula — indeed, it could have the opposite effect. For Pyongyang, tolerating South Korea’s nuclearization would mean losing its sole advantage over the conventionally superior South. Therefore, the period during which North Korea wields greatest military supremacy over the South would be prior to Seoul’s nuclear armament, before Pyongyang’s nuclear advantage is compromised. Thus, the risk of North Korea launching attacks on South Korean nuclear sites to prevent nuclearization — similar to Israel’s strikes on Syria and Iraq — is not negligible.
If South Korea managed to avoid a preventive attack from North Korea, withstand international economic and diplomatic pressures during the nuclearization process, and successfully develop a functional nuclear arsenal, it would likely be able to deter a North Korean nuclear attack. The threat of mutual nuclear destruction could significantly reduce the likelihood of a large-scale, all-out war between the two Koreas.
However, existing scholarship suggests that this nuclear-level stability could still increase the risk of conventional-level conflicts. Although the risk of mutual nuclear annihilation might deter large-scale conflict, the “stability-instability paradox” suggests that nuclear weapons could embolden actors to engage in limited-scale provocations under the impression that such conflicts would not escalate into full-blown war. The 1999 Kargil War between India and Pakistan vividly illustrates this phenomenon. After acquiring nuclear weapons in 1998, Pakistani leaders believed that the threat of nuclear escalation would deter India from launching a large-scale attack, which emboldened them to initiate a limited conflict on the Indian side of the disputed Kashmir territory. Similarly, a nuclear South Korea, emboldened by its newly acquired capabilities, and an already provocative North Korea could find themselves clashing under the assumption that such conflicts would remain relatively limited in scale.
Until recently, such concerns about South Korean decision-making would have been easily dismissed. In democracies, major national security decisions are typically made through consultation with civilian and military advisors, with cooler heads prevailing. South Korea, as a flourishing democracy, has long been perceived as a rational and responsible actor. If it were to acquire nuclear weapons, the assumption has been that it would do so purely to deter its erratic and dangerous nuclear-armed neighbor.
The narrative has been simple: the North is the unpredictable provocateur while the South is the stable and benign counterpart. However, revelations regarding Yoon’s actions related to declaring martial law, seriously undermine confidence in South Korea’s ability to act responsibly.
As investigations continue, mounting evidence suggests that Yoon attempted to bait Pyongyang into a military clash to justify declaring martial law. On November 28, shortly before the December 3 martial law declaration, Yoon’s defense minister, Kim Yong Hyun, widely regarded as the chief conspirator behind Yoon’s martial law order, allegedly ordered a strike on locations inside North Korean territory from which North Korea’s trash balloons originated. Though he denied any connection to the martial law declaration, Kim admitted to contemplating the strike, which another key accomplice, Roh Sang-won, acknowledged having discussed with Kim. Notes confiscated from Roh’s notebook further revealed that Kim’s plan suggested a plot to “induce an attack from the North at the Northern Limit Line,” the disputed maritime border between the two Koreas. If carried out, these actions would have significantly escalated hostilities with the North.
This was not the first time the Yoon administration considered deliberately provoking North Korea into a military confrontation. In mid-October, when Yoon was already preparing for martial law, South Korean drones infiltrated North Korean airspace, reaching as far as Pyongyang, violating the 1953 Korean Armistice Agreement. While the Ministry of Defense initially denied the allegations, it has since refused to confirm or deny the operation following the emergence of evidence. The operation appears to have lacked a strategic goal given that South Korea already has advanced surveillance capabilities to monitor North Korea and the drones were not deployed for a combat mission. Moreover, these particular drones were loud enough to be heard from a long distance, making it more of a provocation than a covert operation. Taken together, these facts support suspicions that the true objective was to provoke the North to create a pretext for declaring martial law.
Fortunately, Pyongyang refrained from responding to Seoul’s provocations, possibly due to its reluctance to engage in a military conflict while a significant portion of its troops, weaponry and ammunition were deployed to support Russia’s war efforts in Ukraine. Under different circumstances, such actions could have risked igniting a local confrontation, potentially escalating into a large-scale conflict. If Seoul can act with such recklessness even without nuclear weapons, how much more emboldened might it become if it were to acquire them?
Some may dismiss these concerns, arguing that such events will not be repeated now that Yoon has been impeached and is likely to be removed from office. They might contend that South Korea’s democracy was swiftly restored after the brief imposition of martial law, and therefore fears of a “madman with nukes” are not warranted in South Korea’s future.
Before advocating for nuclear weapons, South Korea must first restore its democracy and the rule of law to rebuild trust that it can act as a responsible state.
Think again. The challenges facing South Korea’s democracy run deep. Its system of checks and balances is faltering, and its rule of law has been significantly undermined. Despite Yoon’s efforts to paralyze the opposition-led legislative branch, the majority of lawmakers in the ruling People’s Power Party (PPP) continue to support him. On December 3, only 18 out of 108 PPP members voted to lift martial law. PPP Floor Leader Choo Kyung-ho is currently under investigation for allegedly attempting to obstruct the lifting of martial law. Even Yoon’s impeachment narrowly succeeded after two attempts, with only two and seven PPP members voting in favor during the first and second proceedings, respectively.
Furthermore, Yoon and the PPP have sought to undermine the judicial branch’s ability to confirm the impeachment by attempting to block the appointment of new Constitutional Court justices. He has also defied an arrest warrant by using his security guards as a personal militia — a brazen subversion of the rule of law. Over 40 PPP members gathered outside his residence to support Yoon’s obstruction of justice.
In addition, several high-ranking military commanders carried out Yoon’s illegal martial law orders on December 3, demonstrating loyalty to an individual leader rather than the constitution. This politicization and privatization of the military raises the alarming possibility that military forces, including nuclear weapons, could be used at the whim of a single leader. In such a context, there is no guarantee that South Korea would act responsibly as a nuclear-armed state.
For the United States, this is a dangerous scenario because Washington and Seoul are treaty allies, committed to mutual defense in the event of an external attack. A conflict on the Korean Peninsula would thus directly implicate the United States and its interests.
This is not to entirely rule out the option of nuclear armament for Seoul. North Korea’s continued possession and enhancement of its nuclear arsenal is certain for the foreseeable future. And despite U.S. assurances of its commitment to extended deterrence and South Korea’s defense, South Korea may feel that developing and controlling its own nuclear weapons would be the best way to ensure its security with or without international support. However, as it stands, South Korea’s faltering democracy only reinforces international doubts about nuclear armament.
A nuclear-armed South Korea led by someone like Yoon could threaten peace and stability. This concern is further heightened by the fact that some of the most prominent advocates for nuclear armament —including Minister of Employment and Labor Kim Moon-soo, Daegu Mayor Hong Jun Pyo and Seoul Mayor Oh Se Hoon – all leading presidential hopefuls for the next election— are also among Yoon’s most vocal supporters.
Before advocating for nuclear weapons, South Korea must first restore its democracy and the rule of law to rebuild trust that it can act as a responsible state. This is crucial to address concerns that South Korea’s acquisition of nuclear weapons could heighten the risk of conventional conflicts between the two Koreas — conflicts that could escalate to the nuclear level and endanger U.S. and global security.
Lami Kim is a professor at the Daniel K. Inouye Asia-Pacific Center for Security Studies, a U.S. Department of Defense Institute based in Hawaii. The views expressed are those of the author and do not necessarily reflect the official policy or position of the U.S. Department of Defense or the U.S. Government.