Nuclear Implications of the Washington Declaration and Changes in Indo-Pacific Nuclear Developments

Eunjung Lim is Associate Professor in the Division of International Studies at Kongju National University, a board member of Korea Institute of Nuclear Nonproliferation and Control (KINAC), and a member of Policy Advisory Committee for the Ministry of Unification.

The year 2023 marks the 70th anniversary of the Korean War Armistice Agreement as well as the 70th anniversary of the Mutual Defense Treaty, which formalized an alliance between South Korea and the United States. However, the situation on the Korean Peninsula has not been good. Since the so-called “Hanoi No Deal” between Donald Trump and Kim Jung-un, North Korea has been on a rampage. As of October 5, 2023, North Korea conducted more than 20 missile launches—as well as drone launches— since January 1.

Meanwhile, the winds of change have begun to blow in South Korea. The conservative government of President Yoon Suk Yeol has accelerated the restoration of ties with Japan, despite much domestic opposition. His visit to Tokyo in March, and Japanese Prime Minister Kishida Fumio’s reciprocal visit to Seoul in May, were hailed as the restoration of shuttle diplomacy after a 12 year hiatus. While relations between Seoul and Tokyo were improving, another major event occurred. In April, President Yoon made a state visit to the United States, and the “Washington Declaration” was adopted on April 26.

This article aims to provide an understanding of how the discourse surrounding nuclear weapons in the Indo-Pacific region, centered on the Korean Peninsula, has changed especially after the Washington Declaration. The article first examines the implications of the Washington Declaration, then discusses the outcomes of the trilateral summit between U.S. President Joe Biden, President Yoon, and Prime Minister Kishida at Camp David in August, and assesses how these developments are affecting the dynamics surrounding nuclear weapons in the Indo-Pacific region.

First and foremost, the most important implication of the Washington Declaration is the reaffirmation and strengthening of the extended deterrence provided by the United States. The Washington Declaration emphasized that South Korea “has full confidence in US extended deterrence commitments.” It also reaffirms that any nuclear attack by North Korea against South Korea will face a “swift, overwhelming and decisive response.” This is the first time the leaders of South Korea and the United States have adopted a separate document on extended deterrence.

In addition, the declaration goes on to announce the establishment of the Nuclear Consultative Group (NCG) and a new bilateral, interagency table-top simulation to strengthen the joint approach to planning for nuclear contingencies. The two leaders also agreed to increase the frequency of deployments of U.S. strategic assets, such as Ballistic Missile Submarines (SSBNs) to South Korea, and to expand and deepen cooperation between the two militaries. In fact, in mid-July, two-and-a-half months after the Washington Declaration, the USS Kentucky (SSBN-737), an Ohio-class nuclear ballistic submarine, docked at a naval base in Busan, for the first time in 42 years.

The Washington Declaration, however, was met with mixed reviews in South Korea. One of the most hotly debated questions was how the extended deterrence enhanced by the Washington Declaration differs from NATO’s nuclear-sharing in Europe.

However, the critiques are misplaced. First, the situations in Europe and East Asia are qualitatively very different. In Europe, dozens of countries work together as a team to deter a single nuclear-armed state, Russia. In East Asia, the number of countries is much smaller, and while Russia and China are two of the largest nuclear-armed states in the world, and even North Korea is a de facto nuclear-armed state, the rest of the region does not have nuclear weapons. Moreover, while Europe is connected by land, East Asia is separated by sea. Therefore, NATO-style nuclear sharing does not necessarily apply to East Asia and the Washington Declaration and NATO’s nuclear sharing are in competition with each other.

In fact, the request to discuss NATO-style nuclear-sharing was raised by former Japanese Prime Minister Shinzo Abe shortly after the war in Ukraine broke out. Along with Abe’s long-standing dream of normalizing the Japanese state, NATO-style nuclear sharing was also sparked by him to be discussed in Japanese political circles, and Kishida showed an ambiguous attitude, saying that it could be discussed within the Liberal Democratic Party rather than at the government level. As we know, Abe was murdered in July 2022. On the other hand, at the time of the outbreak of the war in Ukraine, South Korea was in the midst of a presidential election, so it was not yet clear which stance the country would take regarding the war. Regardless, it is hard to deny that the war in Ukraine served as a rallying cry for conservative politicians both in South Korea and Japan to push for greater security in their countries.

The second most discussed issue after the Washington Declaration is whether the extended deterrence is sufficient to ensure peace on the Korean Peninsula. As mentioned, the Washington Declaration is certainly an upgrade over the existing one. None of the bilateral agreements that South Korea and the United States have been on the level of the Washington Declaration.

Nonetheless, critics were unsatisfied that the Washington Declaration reaffirms South Korea’s “longstanding commitment to its obligations under the Nuclear Nonproliferation Treaty.” Some of them were politically motivated to oppose anything President Yoon does, while others were nationalists who want to achieve self-defense rather than rely on the U.S. nuclear umbrella.

While there is considerable overlap between the former and latter, it is worth noting that the latter exists in both left- and right-wing camps. However, it is the latter that can be more problematic from an alliance management perspective. Nationalists are more concerned about the asymmetric nature of the South Korea-US alliance and the possibility of abandonment from the United States, and often argue that self-defense, including the possibility of nuclear armament, is the only way to solve problems with North Korea. As these opinions often stir up public sentiment, it is necessary for Seoul and Washington to continue practical efforts to allay these concerns in order to ensure the stable management of the alliance and the effectiveness of extended deterrence.

How did public opinion change in South Korea after the Washington Declaration? Needless to say, the majority of South Koreans are very worried about North Korea’s growing nuclear and missile capabilities, and this anxiety is translated into support for either self-nuclear armament or redeploying U.S. tactical nuclear weapons. While the numbers vary by institution, roughly 60 to 70% of South Koreans seemed to support self-nuclear armament.

These numbers have improved since the Washington Declaration. A public opinion survey conducted by the Korea Institute for National Unification (KINU) in 2023 was titled “Public Opinion on South Korea’s Nuclear Armament.” According to KINU, which has been conducting the same survey for years, public opinion in favor of self-nuclear armament is declining. Support for nuclear armament was at its highest (71.3%) in 2021, and it began to decline in 2022, reaching 69%, and it was 60.2% in the 2023 survey.

Considering that between 2021 and 2023, North Korea’s missile provocations became more frequent and the relationship between the two countries deteriorated, KINU analyzes that the decline in the need to possess a nuclear arsenal was influenced by domestic political factors and the fact that the issue of nuclear armament was more publicly discussed. Also, it can be said that the war in Ukraine did not have a significant impact on South Korean public opinion on nuclear armament. Similarly, public opinion calling for the redeployment of U.S. tactical nuclear weapons to South Korea has also declined since 2021. It was 61.8% in 2021, 60.4% in 2022, and 53.6% in 2023.

The results of the above survey show that the South Korean public is aware of the various disadvantages or crises that could occur if South Korea actually developed nuclear weapons and that the United States does not want South Korea to develop nuclear weapons. When the respondents were presented with six possible crises that could occur if South Korea attempted to develop nuclear weapons and asked if they thought it was necessary to develop nuclear weapons, the percentage who agreed with the idea dropped to between 36% and 37%, respectively. This is in stark contrast to other surveys that have shown support for nuclear weapons at over 70%, according to KINU.

It also proves that the majority of South Koreans trust the nuclear umbrella policy and believe it protects the country from the North Korean nuclear threat. While 72.1% of all respondents said they trusted the U.S. nuclear umbrella policy, 85.3% of supporters of the ruling People Power Party (PPP) said yes. In addition, 68.5% of all respondents and 75.6% of PPP supporters said that the U.S. nuclear umbrella prevents North Korea from attacking South Korea with a nuclear weapon.

Interestingly, the Washington Declaration was released during this year’s survey, and half of the respondents (504) were surveyed before the declaration and the other half (497) afterward, so the results were almost like a natural experiment, KINU explains. If the change in public opinion before and after April 27 is statistically significant, we can consider it an effect of the Washington Declaration.

Favorability toward the US, Japan, and Russia increased after the summit, while there was no significant change in favorability toward China and North Korea. It is interesting to note that perceptions of the United States improved overall after the summit, and favorability toward Japan increased significantly. This may reflect the idea that the outcome of the Yoon-Biden summit will have a positive impact on South Korea’s relationship with Japan. Not only did the perception of Japan as a current military threat decrease, but there was also a clear improvement in the perception of Japan as a future military threat before and after the summit. Meanwhile, confidence in the U.S. nuclear umbrella rose from 68.7 % to 75.6 % after the summit.

In brief, the tide has shifted somewhat since the Washington Declaration, which led to the trilateral summit between South Korea, the United States, and Japan at Camp David on August 18. At the trilateral summit, the leaders of the three countries adopted three documents: a joint statement called the “Spirit of Camp David”; the “Camp David Principles,” which outlines the framework for trilateral cooperation; and the “Commitment to Consult,” which commits the three countries to cooperate in times of crisis. The fact that the three countries have made clear their goal of “denuclearization of North Korea” and have agreed to cooperate militarily and in other fields is certainly a significant change. Therefore, it can be argued that without the Washington Declaration, and without the improvement in relations between Seoul and Tokyo, the agreement at Camp David would not have been possible.

A number of minilateral approaches are now open for discussion. For example, it is interesting to note that a proposal recently emerged in the UK Parliament that South Korea and Japan should be invited to join AUKUS, the US-UK-Australia trilateral security cooperation. The House of Commons’ Foreign Affairs Committee released a report titled “Tilting Horizons: The Integrated Review and the Indo-Pacific” on August 30, stating that the UK government should propose to the United States and Australia that South Korea and Japan join the AUKUS advanced defense technology cooperation agreement.

After all, the tide of increased security cooperation that began with the Washington Declaration between South Korea and the United States has extended to Japan, and there is now a sense that it may spread to other US regional allies. This indicates that the realignment of power in the Indo-Pacific region will accelerate in the near to medium term.

The problem is that this realignment could end up solidifying the continental versus maritime power mentality. North Korea’s Kim Jong-un is trying to maximize his leverage in this game. North Korea has already aligned itself with Russia. Kim Jong-un’s extended visit to Russia and visit to the Vostochny Cosmodrome in September, less than a month after the Camp David summit, had major political ramifications. As Russia is a technological powerhouse in the space and nuclear sectors, it is understandably concerned about the potential for technology transfer to North Korea. Beijing seems to have mixed feelings about Pyongyang’s proximity to Moscow, and is very unhappy about the growing presence of European countries in the Indo-Pacific region. The sharper the divide and the higher the tension, the greater the risk of an unexpected accident or miscalculation surrounding the use of nuclear weapons. This is where risk management wisdom comes in.