South Korean Nuclear Nonproliferation Pivot Points: For years, North Korea has threatened to use its nuclear weapons to annihilate South Korea and the United States. At the end of 2023, North Korea’s leader Kim Jong-un repeated this threat in renouncing peaceful unification. Now that North Korea may have enough fissile material to produce 90 or so nuclear weapons, it may have the ability to annihilate South Korea, and within a few years may also be able to annihilate parts of the United States.
The large and growing North Korean nuclear weapon force has created a pivot point for South Korea, with many in the South unsure that they can blindly depend on the U.S. nuclear umbrella to deter North Korean nuclear weapon use. A growing number of South Korean officials are calling for South Korea to build its own nuclear weapons to deter the North.
As long as the United States is prepared to demonstrate its commitment to South Korea, I believe that it is premature for the South to be building its own nuclear weapons. There are many potentially serious negative consequences if the South pursues this approach. In particular, the U.S. government feels strongly that its nuclear umbrella is preferable to South Korean possession of nuclear weapons, which could lead to a failure of the nuclear Nonproliferation Treaty, leading to many countries each pursuing nuclear weapons. The United States has felt that the world will be a safer place if fewer countries possess nuclear weapons. The U.S. feelings are so strong that a South Korean nuclear weapon development program could jeopardize the U.S./ROK alliance.
U.S. Air Force Elephant Walk in 2022.
But many in South Korea require greater reassurance from the United States. In January 2023, South Korean President Yoon Suk Yeol expressed concerns about the adequacy of U.S. extended deterrence, including its nuclear umbrella: “What we call extended deterrence was also the U.S. telling us not to worry because it will take care of everything, but now, it’s difficult to convince our people with just that.” In particular, Yoon argued that, “While the nuclear weapons belong to the U.S., intel sharing, planning, and training should be done jointly.” To underline this requirement, Yoon said “that if North Korea’s nuclear threat grows, South Korea would consider building nuclear weapons of its own…”
The United States was sensitive to this concern and arranged a summit meeting during which Yoon and President Biden unveiled the Washington Declaration that established a Nuclear Consultative Group (NCG) to address Yoon’s concerns. Indeed, Yoon apparently felt so hopeful that he renounced South Korean efforts to build its own nuclear weapons as part of this declaration. The NCG held its third senior meeting on June 10, though the NCG working-level personnel have been operating continuously.
Despite the formation of the NCG, the growing North Korean nuclear weapon threat and other factors have motivated more South Korean officials to call for South Korea to build its own nuclear weapons. South Korean public opinion polls have shown for years that 60 to 70 percent of South Koreans favor the South acquiring nuclear weapons. And in December 2023, only 39 percent of South Koreans polled thought that the United States would use nuclear weapons in response to a North Korean nuclear attack, a decline from the 51 percent recorded in December 2022. This reflected a serious erosion in South Korean trust of the U.S. nuclear umbrella.
Part of the current problem may be that the NCG efforts have generally not had much public exposure. Many of my Korean colleagues have related concerns about what the NCG may be addressing and expressed hope that details about its deliberations will be publicly disclosed soon. In particular, these concerns fall into six areas.
First, there is clear South Korean concern about the level of U.S. will and commitment associated with its nuclear umbrella. Many Americans have difficulty understanding this, since in peacetime the current U.S. administration has repeatedly stated that the nuclear umbrella is a “rock solid” guarantee. But many Koreans view the U.S. failure to rein in the North Korean nuclear threat as evidence of a weak U.S. commitment. They also worry that the nuclear umbrella may no longer be a guarantee if Donald Trump is elected as the next U.S. president. And they worry that the U.S. nuclear umbrella might not be applied once North Korea has ICBMs capable of delivering nuclear weapons against U.S. cities. They fear that the United States would not be prepared to “trade New York for Seoul,” similar to concerns expressed by the French during the Cold War.
Second, while UN and U.S./allied actions to stop North Korean nuclear weapon growth have failed, the United States and South Korea do not appear to be experimenting with further actions to achieve this objective. While stopping this growth will not be easy, there are options available that could be pursued by the United States and South Korea as part of the NCG efforts.
Third, many South Korean security experts think that Koreans have more interest and expertise in determining how to deter North Korean nuclear weapon use than do their U.S. counterparts. Thus, Yoon called for South Korea to have a major role in planning deterrence of North Korean nuclear weapon use and of the nuclear weapon strategy and targeting that underlie that deterrence, roles from which South Korea has traditionally been excluded. For many years, the United States apparently worried that the more it discussed nuclear weapons with South Korea, the greater South Korean interest would be in having its own nuclear weapons. But the growth in the North Korean nuclear weapon threat has created a pivot point where the less the United States discusses nuclear weapons with South Korea, the greater South Korean interest may be in having its own nuclear weapons.
In addition, “most South Koreans believe that their continued alliance with the United States will end up dragging Seoul into a nuclear war it otherwise could have avoided. … South Koreans have significantly higher levels of trust in their own government’s ability to make responsible nuclear choices than they do in an ally.” Hopefully, the NCG is recognizing and addressing these South Korean concerns.
Fourth, many South Koreans wish to be treated as a trusted and powerful ally. They feel that historically South Korea has been treated very much as a junior partner in the alliance, and view Yoon’s requests for a South Korean role in intelligence sharing, planning, and training of nuclear weapon use would be a part of moving beyond the junior partner role. The NCG efforts could be key in demonstrating that this transition is occurring.
Fifth, some South Koreans are anxious for an independent South Korean ability to employ nuclear weapons. They view the U.S. nuclear weapon sharing in Europe as one step in this direction, and seek a similar arrangement. But the United States is unlikely to take such a step, as many Americans are not happy with nuclear weapon sharing in Europe and the United States has reduced the nuclear weapons shared substantially.
North Korean ICBM. Image Credit: KCNA/North Korean State Media.
Finally, some in South Korea are not certain that the United States has the nuclear forces that would be required to respond to North Korean nuclear weapon use if the United States faces simultaneous conflicts with North Korea, Russia, and China. While such a scenario is unlikely, its possibility raises concerns about the adequacy of U.S. nuclear deterrence. A recent bipartisan congressional commission also expressed concerns about the adequacy of the U.S. strategic nuclear weapon modernization program especially with regard to the substantial ongoing build-up of the Chinese nuclear weapon forces. The United States could address this concern in the NCG in part by dedicating some U.S. nuclear forces to targeting North Korea.
If the United States, working through the NCG, can address these issues and demonstrate that its efforts to counter the North Korean nuclear weapon threat really do go beyond its words, South Korean interest in nuclear weapons should be moderated for now. But unless greater U.S./South Korean action is taken to rein in the growth in the North Korean nuclear weapon threat, a second pivot point may be coming that could lead to South Korean nuclear weapon development, much as Yoon has indicated.
About the Author: Dr. Bruce W. Bennett
Dr. Bruce W. Bennett is a senior international/defense researcher at RAND, a nonprofit, nonpartisan research institution. He works primarily on research topics such as strategy, force planning, and counterproliferation within the RAND International Security and Defense Policy Program.
Image Credit: Creative Commons.
