Expanded Deterrence Strategy: Is South Korea Turning into a Nuclear Power?
In April 2023, a secretive meeting took place in Seoul, South Korea, involving several “high-level” figures to discuss the possibility of South Korea acquiring nuclear weapons. This was the first meeting of the Nuclear Policy Forum. Although the idea had been marginal for decades in South Korea, it has recently gained significant traction, with over 70% of South Koreans supporting the notion of the country becoming a nuclear power. This paper aims to examine and analyze the motivations behind this shift.
South Korea’s efforts to develop nuclear weapons are not new. The first attempts occurred in the 1970s, but the United States intervened, giving Seoul the choice between continuing its nuclear development or accepting U.S. protection through its entire nuclear arsenal. South Korea chose the latter, a decision it adhered to for decades. However, recent changes in the security and geopolitical landscape have prompted a reevaluation of this stance.
In this context, South Korean state research centers have highlighted an urgent need for Seoul to arm itself with nuclear weapons. This concern is driven by Russia’s suspicious activities in deepening cooperation with North Korea, including a joint defense agreement, and South Korea’s growing belief that the credibility of the U.S. deterrence strategy is waning, particularly in the Indo-Pacific region.
What is the Expanded Deterrence Strategy Employed by the United States?
The expanded deterrence strategy involves the U.S. using its military power, including its nuclear arsenal, to defend its allies in South Korea, Japan, and Taiwan. This approach emerged after World War II when a new global order was established. Over the years, this strategy has faced challenges from adversaries who now question the effectiveness of the U.S. deterrence in a dramatically changed international environment. This skepticism contributes to concerns about the growing nuclear ambitions of U.S. allies in the South China Sea region, necessitating a reassessment of the deterrence strategy to enhance its effectiveness. This includes redesigning the strategy to allow for more dynamic use of nuclear and conventional weapons and restructuring alliances to increase deterrence efficacy.
The U.S. needs to address two main aspects: the first involves deterrence against adversaries, aimed at preventing them from initiating attacks. The second involves assurances to allies, providing reassurance that the U.S. will indeed protect them. Thus, the two strategies can be summarized as shaping the opponent’s perception of the credibility of deterrence and protection.
Functionally, assuring allies is more challenging than deterring adversaries. Allies are generally reluctant to gamble with their security, necessitating ongoing efforts. The deterrence strategy, established since World War II, relies on threatening the use of force to convince adversaries that the cost of an attack or invasion will far outweigh any potential gains. The effects of deterrence are more pronounced when countries possess military nuclear power.
Donald Trump’s presidency presented a significant challenge for U.S. allies, as he criticized these alliances extensively, creating a crisis of confidence in U.S. commitment to their security. This prompted some countries, like Vietnam, to seek alternatives, evidenced by signing eleven agreements with Russia, including one on nuclear technology transfer. This raises concerns about the militarization of nuclear states, especially in the Indo-Pacific region.
At times, deterrence or assurance strategies might lead some countries to attack adversaries before realizing they lack genuine protection from the U.S. if they proceed with such an attack or provoke an adversary, as seen in the Taiwanese case. However, there is no real evidence that the U.S. has lost its deterrent capability, as no country has withdrawn from the Nuclear Non-Proliferation Treaty.
The deterrence strategy in the Indo-Pacific holds particular significance due to the region’s sensitivity and existing tensions from China’s ambition to dominate the South China Sea. The U.S. expanded deterrence strategy is notably effective in this region, leveraging both conventional and nuclear capabilities to counter security challenges posed by China. Of the 32 treaties the U.S. has signed globally to enforce its expanded deterrence strategy, most are within NATO’s framework, but there are also significant bilateral defense treaties with countries outside the alliance, including South Korea, Japan, the Philippines, Taiwan, Thailand, and Australia.
Currently, amidst geopolitical shifts, alternative deterrence measures like economic sanctions have proven ineffective against adversaries, as evidenced by the cases of Russia, Iran, and North Korea. This underscores the continued importance of traditional deterrence methods involving conventional and nuclear weapons, signaling an increase in nuclear ambitions among many nations.
Russian-North Korean Cooperation
Pyongyang and its nuclear strength are the primary factors driving Seoul to consider developing its own nuclear military capability. This consideration is fueled by North Korea’s recent escalations, which have heightened concerns following the signing of a joint defense agreement between Moscow and Pyongyang. This agreement has raised apprehensions about the prospects of this cooperation and the potential threat if either country were to be attacked. Adding to these fears, Russian President Vladimir Putin, contrary to all UN Security Council sanctions, declared that Pyongyang possesses nuclear weapons. This declaration suggests that other nations, notably China, might formally recognize North Korea as a nuclear state. According to a study from a South Korean government-affiliated research center, Seoul needs to diversify its options, including reconsidering the deployment of tactical nuclear weapons.
In this context, the fact that North Korea is an unofficial nuclear power plays a significant role in the growing nuclear ambitions in the Indo-Pacific region. Pyongyang’s refusal to engage in US-led nuclear disarmament talks has created uncertainty regarding the credibility of the US nuclear deterrent. Additionally, North Korea’s nuclear doctrine, which emphasizes preemptive strikes, adds to the region’s volatility.
Furthermore, Russia’s involvement in this dynamic raises concerns about Pyongyang’s role in supplying Moscow with weaponry used in Ukraine, due to shortages in Russian ammunition stocks. Moscow’s support to North Korea, exemplified by assisting in launching a satellite for espionage purposes after previous attempts failed, suggests a focus on acquiring weaponry rather than seeking protection from Pyongyang. This development increases the likelihood of a third world war, particularly after the US and Europe provided Ukraine with offensive weapons and allowed it to target objectives within Russia.
Third: Chinese Practices in the South China Sea and the Vietnamese Situation
China’s actions in the South China Sea are equally significant in driving nuclear ambitions in the Indo-Pacific region, especially given the erosion of US credibility and deterrent capability. For example, Beijing has managed to stir concerns in Japan over disputed islands through a combination of civil, military, and diplomatic measures.
This decline in US credibility in the Indo-Pacific can only be countered by strengthening security partnerships in the region with key countries like Indonesia, the Philippines, and Malaysia. The situation is complicated by Russia’s engagement, which includes signing eleven agreements with Vietnam, including one on nuclear technology transfer. This move has precluded the US from securing such agreements first, particularly since Vietnam is a crucial economic player in the region. Key facts about Vietnam’s importance include the presence of the US Seventh Fleet off its coast, the passage of 30% of global trade through its territorial waters, and significant natural resources in the South China Sea, shared with the Philippines, Malaysia, Brunei, and Indonesia. Thus, the US military presence in the Pacific, or what China refers to as the South China Sea, is its largest military deployment outside its borders.
Additionally, there are ongoing disputes between China and Vietnam over the South China Sea and other borders. The US aims to use Vietnam to deter China from invading Taiwan, but Russia’s current strategy involves leveraging Vietnam to serve Chinese interests and isolating Hanoi from the US. Despite US attempts to include Vietnam in an alliance with Taiwan, South Korea, and Japan, which would weaken the China-allied bloc in the region, these efforts have failed. Russia is playing a mediating role, working to distance South China Sea nations from the US, including Vietnam, by arming these countries and facilitating nuclear technology transfer. Thus, it is crucial for the US to leverage its security partnerships in the Indo-Pacific by enhancing allies’ nuclear capabilities to match potential adversaries.
The third factor involves ongoing consultation with US allies in the Indo-Pacific and establishing advisory mechanisms similar to those between the US and NATO. Such mechanisms would enhance allies’ confidence by involving them in strategies and decisions that provide protection.
Finally, China’s practices reveal ambitions that extend beyond invading Taiwan or controlling the South China Sea. Beijing views the global order as fundamentally flawed and in need of restructuring based on new foundations, including its relationships with neighbors, international powers, and its opaque nuclear arsenal. The steady growth of Beijing’s nuclear stockpile gives it flexibility to adapt its strategy to nearly all changes and emergencies.
Cooperation Between the United States and South Korea
In recent years, particularly after the Russian-Ukrainian war, the United States has faced numerous challenges that threaten its influence and alliances. This situation has necessitated an expansion of its deterrence strategy. The erosion of U.S. credibility in deterrence could strongly motivate both South Korea and Japan to develop their own nuclear capabilities. With shifting dynamics and emerging political, military, and technological factors threatening long-standing strategic balances, countries might move from extended deterrence to extended nuclear deterrence—a strategy continually emphasized by the U.S., which aims to maintain credible and flexible nuclear deterrence.
Building on this context, the South Korean president proposed last year that Seoul might need to consider acquiring its own nuclear weapons to address what it views as challenges in a deteriorating security environment. This dangerous consideration is not limited to South Korea alone; Japan and Australia are also contemplating developing military nuclear technology to counter threats. Japan has been more explicit about its interest, with former Japanese Defense Minister Shigeru Ishiba stating in 2017, “Japan should have the technology to build a nuclear weapon if it wants to do so.” Furthermore, these countries are technically capable of developing nuclear weapons, and the political constraints that once acted as barriers are no longer relevant. As a result, these constraints might not hinder nuclear proliferation but could instead act as a catalyst.
Following Russia’s defense agreement with North Korea, South Korea’s concern increased regarding the potential enhancement of Pyongyang’s nuclear capabilities through this cooperation. This prompted an American aircraft carrier to quickly head to South Korean shores to conduct military exercises intended to send a threatening message to North Korea. South Korea also summoned the Russian ambassador to express its protest against the joint defense agreement with Pyongyang.
In this context, South Korea is attempting to preemptively address the situation by negotiating with the United States to renew the agreement for the redeployment of over 28,000 American troops in the country, prepared to deter any attack from North Korea. This is partly due to concerns that if Donald Trump were to return to power, renewing the agreement might become uncertain. Nevertheless, the agreement remains valid until the end of 2025.
On the other hand, there are scenarios involving the United States and South Korea that focus on integrating nuclear operation simulations into the allies’ military exercises next year. At the same time, the nuclear advisory group has been launched, but there is caution in developing relations between the two sides to avoid misinterpretations in Pyongyang that might suggest a shift from deterrence to a direct threat of using force. Consequently, the two sides have agreed to delay the transfer of command of the United Nations Command forces from the United States to South Korea.
However, South Korea’s nuclear ambitions face several obstacles. Notably, last year, on the occasion of the 70th anniversary of the Mutual Defense Treaty, the leaders of the two countries signed a declaration in which Seoul reaffirmed its commitment to not acquiring nuclear weapons, while Washington renewed its commitment to the protective umbrella. The United States approaches this issue with sensitivity, imposing stricter standards on South Korea regarding nuclear armament.
In conclusion, it is difficult to ignore the growing nuclear ambitions in the Indo-Pacific region. The U.S. extended deterrence strategy needs to evolve in response to global geopolitical changes, especially since this region has been the focal point of U.S. strategy and defense policies since 2012, as part of the “rebalance to Asia” initiative under former President Barack Obama. This region is home to two nuclear powers: China, officially recognized, and North Korea, which is not recognized, posing a threat to two of the U.S.’s most important allies—Japan and South Korea. This situation requires the United States to put in additional effort to reassure its allies, not only to protect these alliances but also to prevent nuclear proliferation.
