During South Korean President Yoon Suk-yeol’s state visit to Washington honoring the 70th anniversary of the alliance between the United States and South Korea, he and U.S. President Joe Biden announced the Washington Declaration. This announcement paves the way for creating a Nuclear Consultative Group (NCG) between the two governments, modeled on nuclear consultative mechanisms within NATO. Through the NCG, the two allies would collaborate on the planning and execution of responses to potential nuclear use by North Korea.
This new framework would likely provide South Korea with a greater voice in preparing for nuclear retaliation, while the United States would still retain in control of its nuclear weapons. As North Korean threats of a preemptive nuclear attack and continued missile tests heighten South Koreans’ sense of vulnerability, the NCG aims to address this growing concern by reinforcing bilateral cooperation over U.S. nuclear strategy. However, a crucial question lingers: Can the NCG effectively address the core issue that may strain the alliance, namely South Korea’s growing demand for its own nuclear weapons program?
Seoul’s Uncertainties and Growing Demand for Self-Deterrence
The root cause of South Korea’s security concerns lies in North Korea’s escalating nuclear threat. However, the uncertainty surrounding South Korea’s national security stems from the South Korea-U.S. alliance itself. Specifically, the unknowns regarding how the United States would respond to a North Korean nuclear attack significantly impact South Korea’s response capabilities.
South Korea faces two main uncertainties: First, would the United States employ its nuclear weapons to counter a North Korean nuclear attack as promised? Second, if it does respond, when, where, and how would U.S. nuclear weapons be used on the Korean Peninsula?
Knowing the answers to these questions is critical for South Korea. The country relies on the United States for a significant portion of its national security and has relinquished its right to possess nuclear weapons. However, if Washington fails to uphold its promise to respond to a North Korean nuclear attack, or if it carries out nuclear retaliation at an unexpected time and in an unanticipated manner, South Korea’s security could face even greater threats without an adequate means of response. Consequently, Seoul has historically been sensitive to changes or uncertainties in the reliability of U.S. defense pledges. If South Korea loses confidence in U.S. responses, it may seek alternative means to safeguard its security rather than waiting for these uncertainties to place the country in real danger.
These uncertainties have led to a growing demand for nuclear weapons in South Korea. In January 2023, Yoon himself suggested that if the current situation with North Korea continues to escalate without further intervention from Washington, South Korea might consider acquiring its own nuclear arms. While Yoon’s remarks were met with enthusiasm by South Korean nuclear advocates, they also raised strong concerns in the United States. In particular, South Korea’s nuclear proliferation could trigger the Glenn Amendment, which would require the U.S. to cut military and economic assistance, ultimately leading to cracks in the alliance.
However, Yoon’s statement does not mean that South Korea has decided on nuclear armament. Immediately after Yoon’s remarks, the South Korean government reaffirmed that it would comply with its nuclear nonproliferation obligations, and Prime Minister Han Deok-soo clearly stated in an interview with CNN that South Korea does not have any intention to develop nuclear weapons. Rather, Yoon’s statement actually reflected South Korea’s call for greater cooperation from the United States in nuclear planning and execution, as there are increasing concerns and complaints among South Koreans that the U.S. is not being transparent enough in its nuclear strategy.
The NCG and Its Implications
Against this background, the establishment of the NCG represents a timely and measured response to changing domestic situations in South Korea as well as the growing nuclear threat from North Korea. It is important to note that the creation of the NCG would not grant South Korea the authority to decide on the use of U.S. nuclear weapons. The U.S. president would maintain sole authority to order the employment of U.S. nuclear weapons, and that would remain the case. Instead, this establishment would provide a mechanism for South Korea to be consulted in nuclear decision-making and have an opportunity to weigh in when the use of nuclear weapons is considered. Through this framework, South Korea would be able to express its voice at the highest level during a crisis.
Furthermore, a more transparent and consultative nuclear policy between the United States and South Korea would give Seoul insight into U.S. plans, which is crucial for South Korea’s own defense planning. Increased transparency in U.S. nuclear planning and implementation would help build South Korea’s confidence in its partner’s capability and willingness to employ its own forces under the joint defense posture. Ultimately, this will help South Korea in designing its force modernization and military strategies.
Moreover, the creation of the NCG serves to increase the credibility of U.S. extended deterrence by demonstrating a stronger commitment to retaliation in the event of a nuclear attack. The establishment of the NCG creates a “hands-tying” effect, making it clear that the United States would face significant consequences for reneging on its commitment. This provides assurance to South Korea that the U.S. would honor its extended deterrence promises in case of a North Korean attack. Thus, the NCG not only gives Seoul more influence over South Korea’s own national security but also reinforces the U.S. commitment to defend South Korea if needed.
Lastly, the Washington Declaration that established the NCG also reaffirmed South Korea’s commitment to remain in the Nuclear Nonproliferation Treaty, implicitly pledging not to pursue its own nuclear weapons capability. In this context, the South Korean government is committing to set aside the prospect of developing and deploying an independent nuclear arsenal, opting instead for a strong alliance-focused response.
Would the NCG Alleviate South Korea’s Nuclear Demands?
While the NCG aims to address many concerns and improve the alliance, the creation of the consultative mechanism itself would not completely eliminate demands for nuclear armament in South Korea. In particular, nuclear weapon advocates in Seoul will likely claim that the NCG is insufficient if South Korea does not possess nuclear weapons or if U.S. nuclear weapons are not deployed on the Korean Peninsula. Nuclear advocates may continue to demand full NATO-like nuclear sharing with forward-deployed assets.
However, the creation of the NCG would effectively alleviate the South Korean government’s and the public’s concerns. The government is more focused on how to effectively cooperate with the United States on extended deterrence and reduce strategic uncertainties than on possessing nuclear weapons per se. Therefore, the establishment of consultation mechanisms for information sharing, nuclear strategy development, and implementation will play a sufficient role in alleviating its concerns. In addition, the creation of the NCG would also demonstrate to the publics of both countries the specific efforts the two governments are making to deter the nuclear threat from North Korea. This increased collaboration would help to build trust among South Koreans in U.S. pledges and help to dispel concerns regarding how the United States would respond in case of an attack.
With this in mind, the establishment of the NCG would significantly contribute to the stability of the Korean Peninsula without compromising nuclear nonproliferation principles. Most importantly, the NCG would represent a crucial step involving both the United States and South Korea in nuclear matters. This approach would shift the discussion from a “hardware solution” to a “planning solution,” significantly enhancing confidence in U.S. involvement in countering the North Korean nuclear threat on the Korean Peninsula, while leaving the ultimate decision to use nuclear weapons in the hands of the U.S. president.