A Conversation: Japan-U.S.-South Korea Security Cooperation Enters a New Phase

Focus on universal values and stronger deterrence against North Korea—South Korea’s Yoon Suk Yeol administration shifted its basic foreign policy.

By Junya Nishino and Tsuneo Watanabe


Related Articles


Focus on universal values and stronger deterrence against North Korea—South Korea’s Yoon Suk Yeol administration shifted its basic foreign policy. As Tokyo-Seoul, Washington-Seoul, and Tokyo-Washington-Seoul frameworks reactivate, a new style of cooperation for the U.S. extended nuclear deterrence and economic security is called into question.

– The Yoon administration kicked off in South Korea, and the Japan-South Korea and Japan-U.S.-South Korea relations are reactivating. How do you see the Yoon administration’s foreign policy?

Nishino: It has been 13 months since Yoon took office, and the overall picture is coming into view. We could characterize it as implementing foreign and security policies that focus on universal values and power. At his inauguration speech, Yoon stated the importance of values such as democracy, freedom, and human rights, which he has repeated on various occasions. Regarding North Korea, the most serious security concern, while the Moon Jae-in administration stressed North-South reconciliation, the Yoon administration has focused on stronger deterrence in response to the North’s increased nuclear and missile capabilities, as well as deployment and operational readiness. Of course, the Yoon administration is not rejecting dialogue with the Pyongyang. In August 2022, it announced the “Audacious Initiative,” revealing an economic support program in exchange for denuclearization. But overall, it is a strategy of stronger deterrence, reminding Pyongyang that nuclear development is futile and drawing it into dialogue.

Within this foreign and security policy that emphasizes universal values and deterrence by force, the U.S.-South Korea alliance is the core. It is also natural that Japan-South Korea and Japan-U.S.-South Korea collaborations will become critically important. So, we could acknowledge it was a year of pursuit in that direction.

Watanabe: Speaking of a big change, so was the U.S. policy towards South Korea. The Donald Trump administration only focused on the “deals” with North Korea and did not see much value in South Korea’s presence. The Joe Biden administration recognized anew the importance of South Korea as an ally. Meanwhile, with the start of the Yoon administration that values collaboration with the U.S. and Japan, we can see the direction for normalizing Tokyo-Washington, Washington-Seoul, and Tokyo-Washington-Seoul relations. For his April visit to the U.S., Yoon received state guest treatment, and the “Washington Declaration” announced there had substantial content, showing high expectations by the U.S.

As for the U.S., solidarity with like-minded countries is essential when it needs to confront the biggest rival China, and now also Russia, with the war in Ukraine. The reliable countries in the Indo-Pacific region are NATO’s Asia Pacific Partners (AP4: Japan, South Korea, Australia, New Zealand), especially Japan, South Korea, and Australia. Including the U.S., the four countries now share a big strategy and the long defunct Tokyo-Seoul relations have begun to roll at last. This is no doubt favorable when considering Washington’s Indo-Pacific strategy.

– The U.S. and South Korea also seem to be recovering trust.

Watanabe: Yet, we can’t say for sure that Washington has full confidence in the Yoon administration. A progressive administration that prioritizes inter-Korea reconciliation wouldn’t be good, but a conservative administration also has misgivings, and Washington is especially wary of Seoul’s move to possess its own nuclear weapons. Washington does have fears that if it doesn’t keep tabs on Seoul, there’s no knowing where it’ll head.

Nishino: Whether the administration is conservative or progressive, we can’t say for certain Seoul will never consider nuclear armament in the future. In South Korea, a positive atmosphere towards nuclear armament is growing. According to a poll in late 2022, a highest-ever 75 percent agree to the country’s own nuclear development and armament. The moves of North Korea and the Russian invasion of Ukraine is of course behind this trend. Meanwhile, it’s also true that the trust toward U.S. extended deterrence is declining. In the same poll, roughly 50 percent said they cannot trust U.S. extended deterrence. Although the Yoon administration has repeatedly affirmed its commitment to the Nuclear Non-Proliferation Treaty (NPT), domestic debates on the nuclear issue are likely to continue.

South Korean Public Shows Harsh Response to Improved Ties with Japan

– With the Yoon administration announcing the resolution for the wartime forced labor issue in March, relations with Japan improved, and the “shuttle diplomacy” by the two leaders resumed. What is the aim of the Yoon administration?

Nishino: As I mentioned earlier, the fact that Yoon emphasizes the values of freedom, human rights, and the rule of law, and considers them the foundation of international order in Northeast Asia and Indo-Pacific, plays a large role. Since Japan and South Korea share the universal values in the same region, and both are large economies, Yoon deems it natural for the two to cooperate. Moreover, Tokyo-Seoul relations were vital to strengthen ties with Washington. Collaboration between Tokyo, Washington, and Seoul is essential to promote integrated deterrence advocated by the Biden administration. From Seoul’s point of view, mending relations with Japan contributes to strengthening U.S.-South Korea relations. With this aim, the Yoon administration has worked vigorously for a year to improve ties with Japan. The forced labor issue had been the biggest pending problem, but to overcome this, the Yoon administration announced a resolution plan on March 6.

The crux of the resolution was the “third-party compensation method” in which the fund under the South Korean government pays the plaintiffs the reparations in lieu of the Japanese companies. This scheme had been discussed since the Moon administration. But the Yoon administration launched a public-private consultative body in July 2022, and tried to build a consensus through discussions involving experts, government officials, and plaintiffs’ representatives. After four sessions of discussions, the Foreign Ministry announced a draft on January 12, which was met with a fierce backlash from the plaintiffs and support groups. Many voiced the need for a process to seek more understanding. However, with Yoon’s decision, the final resolution plan was announced in March. Welcoming Yoon’s visit 10 days later shows Tokyo appreciated his decision.

Watanabe: As for Washington, it basically welcomed the move. Meanwhile, it is well aware this is a delicate issue and is probably keeping a close watch on the situation.

– How is this viewed within South Korea?

Nishino: The overall reception in Japan is positive, but in South Korea, the majority shows a harsh response. According to a survey by Gallup Korea, 35 percent support the Yoon administration’s solution, while 59 percent are against it. This shows strong discontent for not including Japanese firms’ apology and payment to the fund, which Seoul had initially demanded. It would have been well if the two points were mentioned during Yoon’s Japan visit on March 16-17, or Japan showed some equivalent compromise, or “sincere response,” but it seems none of that happened. So, there is criticism that the South Korean side just made a one-sided concession. Opposition forces are launching a campaign, denouncing it as “humiliating diplomacy toward Japan.”

– For Japan, it seems like a worrisome situation.

Nishino: There is of course criticism towards Japan, but it’s more about the Yoon administration’s policy towards Japan or the administration itself. At the root of this is not just foreign and security policies, but the political and social polarization at home. As evidenced by the fact that last year’s presidential election was decided by a mere 0.73 percent margin, the conservative and progressive forces are in close competition, with divided views for the administration being the norm. For example, polls showed that those who approved and disapproved of Yoon’s state visit to the U.S. were split at 42 percent each.

With this situation, there is a deep-rooted concern in Japan that if the progressives win the next presidential election, bilateral relations will sour again. Though this is quite possible, to prevent the backsliding, we should build a firm base for a sustainable Tokyo-Seoul relations during Yoon’s term. Fortunately, he has four more years in office. South Korea is a democratic country that has presidential elections every five years. With no reelections, the administration changes frequently. We know that the direction of policies changes with each administration, and the fluctuations are wide. It’s important for Japan to not give up on South Korea, but eye the realities of South Korean politics in a composed manner and start building a relationship that will lead to the future. At this point, we should not be overly positive or negative.

The Impact of U.S.-South Korea “Washington Declaration”

– During his April visit to the U.S., Yoon announced the “Washington Declaration” with Biden, aiming to strengthen extended deterrence.

Watanabe: The “Washington Declaration” is a policy document aiming to strengthen extended deterrence, stating that the two countries will establish the Nuclear Consultative Group (NCG) and South Korea will be involved in the American nuclear operations. It also mentions deployment of an American nuclear ballistic submarine to South Korea. Meanwhile, it also stated Seoul’s commitment to the Nuclear Nonproliferation Treaty (NPT). For Washington, this is one solution to the issue of regaining Seoul’s trust on its extended deterrence power toward Pyongyang and Beijing, while restraining the conservative administration’s aspiration to possess South Korea’s own nuclear weapons.

The highlight was the establishment of the NCG by the two countries. It is for sharing U.S. contingency joint operation plans, including nuclear forces. The group was formed as Washington responded to the strong request by Seoul.

Nishino: On the Washington Declaration, views are divided even among the South Korean conservatives. The government hails that the new NCG provides stronger U.S. commitment on extended deterrence, but for those seeking nuclear armament or nuclear sharing, the documentation of Seoul’s commitment to NPT hinders not only nuclear armament but also revision of the U.S.-South Korea nuclear agreement. Therefore, it’s true that there is a critical tone claiming the country is left unable to even enrich plutonium.

Watanabe: Behind the Washington Declaration is South Korea’s distrust of U.S. extended deterrence. In short, this derives from a declining U.S. grip on the security framework. The Biden administration wants to maintain and strengthen overall deterrence by having the allies take on a part of the deterrence the U.S. had been bearing. This is the concept of integrated deterrence, which was stated in last year’s U.S. National Security Strategy, and the creation of the NCG is part of this move.

In fact, the move towards integrated deterrence between Washington and Seoul had already started before the Washington Declaration. In 2021, the Biden and Moon administrations abolished the U.S.-South Korea missile guidelines, which limited the range of the missiles South Korea could develop and possess to 800 km. As a result, South Korea can develop longer-range missiles and respond more flexibly to the threats from North Korea. This has induced Japan to introduce counterattack capabilities by possessing 1,000 km-range missiles.

– What exactly does NCG do?

Nishino: We can’t really say until it starts rolling. Between Washington and Seoul, the Extended Deterrence Strategy and Consultation Group (EDSCG) was created in December 2016 as a framework for consulting extended deterrence. It began during the Park Geun-hye administration and was almost dormant during the Moon administration, but the Yoon administration decided to activate this. How does the NCG differ from this? What’s more, the EDSCG is at the vice-ministerial level while the NCG is at the assistant vice-ministerial level, so the EDSCG could be considered a higher level. On this, the Yoon administration explains the significance of the NCG, saying it only discusses nuclear issues, and while NATO’s Nuclear Planning Group (NPG) has all 29 member states attending, the NCG is a bilateral framework, and likely to more reflect South Korea’s views. But, putting aside how it relates to the EDSCG, when compared to NATO’s NPG, “Consultative” differs greatly from “Planning.” When Kim Tae-hyo, South Korea’s principal deputy national security adviser said, “Our people will effectively feel that they are sharing nuclear weapons with the United States,” a U.S. official dismissed his statement, saying, “I don’t think that we see this as a de facto nuclear sharing,” and there is a perception gap between the two countries, and we need to keep a close eye on the developments.

– In terms of stronger extended deterrence, it’s likely to impact Japan too.

Nishino: At the Seoul Japan-South Korea summit in May, Yoon said in the joint press conference that he does not rule out Japan’s participation in the NCG. We should take that to mean it is okay to have a framework in the future for Tokyo-Washington-Seoul to discuss extended deterrence. I believe Washington also has a similar recognition in terms of integrated deterrence. Yet, we can’t go there in one leap. Japan must first work on closer intelligence sharing between the three countries and accumulate joint military drills; in other words, further develop trilateral cooperation to specific responses for Pyongyang’s military threats. And then, form a trilateral framework to discuss extended deterrence. That’s the proper way to do it.

In fact, the joint statement at the November 2022 Japan-U.S.-South Korea summit in Phnom Penh states, “The leaders intend to share North Korea missile warning data in real time,” and work is in progress to attain this. So, the priority should be solving each issue at hand.

Watanabe: From a different view, instead of just Japan, the U.S., and South Korea, it may be a good idea to consider including more members, as a framework for discussing various security issues. The first that comes to mind is Australia, but it could be a Southeast Asian or European country. It would be tougher to coordinate with more participants, but Japan, the U.S., and South Korea can be susceptible to the political climate of the time. Australia has especially been on good terms with all three countries, so a quadruple framework may be good for cool-headed discussions. Or it could be collaboration with the Association of Southeast Asian Nations (ASEAN) or NATO.

Nishino: I also think Japan, South Korea, the U.S., and Australia is a possible framework. The security cooperation between Japan, the U.S., and Australia is already underway and South Korea and Australia have the Foreign and Defense Ministers’ Meetings (2+2) and have close ties. The Yoon administration initially intended to join the Quad (Japan-U.S.-Australia-India), but that is unlikely to happen as of now, and also with India that advocates non-alliance, it may not be an ideal framework for the Yoon administration that promotes a foreign policy focusing on universal values and power. In contrast, the AP4 that Watanabe-san mentioned is a framework that suits the stance of Yoon’s diplomacy. Yoon, along with Japanese Prime Minister Fumio Kishida joined the NATO summit in June 2022 and South Korea is strengthening ties with Europe, such as setting up a mission to NATO. The AP4 is an attractive framework for the Yoon administration, in which it can promote ties with Europe and others while also deepening cooperation among the allies of the U.S. in the Indo-Pacific region.

Economic Security Is a Common Concern for Japan and South Korea

– Economic security was also an important theme at the U.S.-South Korea summit.

Watanabe: For the U.S., the biggest geopolitical rival is China and economic security is becoming increasingly vital to deter its dramatically advancing military technologies. The economic de-risking, mainly in advanced technologies, is where Tokyo, Washington, and Seoul should unite, but it’s not that simple in the economic context. In October 2022, the U.S. announced the tightening of semiconductor export restrictions to China, which applies to not only Chinese companies but also South Korean and other foreign chipmakers. Taiwanese and South Korean companies are the ones mostly producing high-spec semiconductors, so Seoul wants to ensure as much easing or postponing of the restrictions as possible through talks with Washington. For Seoul, economic security involves both geopolitical concerns toward Beijing and economic concerns toward Washington, making it difficult.

Nishino: Regarding restrictions imposed on South Korean companies by the U.S. Chips and Science Act, South Koreans were most concerned about how much concession Seoul could extract from Washington. In the semiconductor field, Samsung Electronics had announced building a new plant in Texas, and U.S. investments by South Korean firms are said to have exceeded $100 billion since the start of the Biden administration. There is much domestic criticism that despite its considerate move to speed up the shift to the U.S., South Korea not only got nothing in return, but has also been subjected to chip export restrictions.

Like Watanabe-san said, for South Korea, the U.S. is economically important, but the Chinese market remains significant too. It is moving towards differentiation, such as producing next-generation semiconductor which requires advanced technology in the U.S. and making general purpose semiconductors in China. But if U.S. industrial policies lead to more “friendshoring,” i.e., securing supply chains within allies, the South Korean companies will face an even tougher situation. This concern is the same for Japan.

– Does Washington understand its allies have these dilemmas?

Watanabe: Not really; the congress in particular. With deepening political polarization, it is hard to form a consensus on the South Korean side, like, “since the U.S. is a vital ally for South Korea’s security, let’s meet them halfway with their egoism.” Meanwhile, the semiconductor industry is a key area for South Korea, and the Chinese market is essential for its growth.

If the de-risking expands further, the South Korean as well as the Japanese economies will suffer serious effects. Tokyo and Seoul should exchange information on this issue and if Washington seems to go overboard with restrictions, they should work together to negotiate. But in reality, they were doing the opposite, and Japan and South Korea were having export control arguments.

Nishino: Under the Washington-Beijing strategic war, Tokyo and Seoul share many problems. For both Japan and South Korea, relations with the U.S. is top priority, but they both need to avoid being too confrontational toward China. At the Japan-South Korea summit meeting in March, the leaders “agreed on the importance of resuming the high-level Japan-South Korea-China process as soon as possible.” This is probably because both countries find it meaningful to manage their relations with China in a steady way by holding a trilateral summit this year. Since South Korea is the current host country, Tokyo and Seoul will cooperate to hold the event.

The Three Have Varying Attitudes towards Beijing

– Does Seoul have a different degree of enthusiasm on the Japan-Washington-Seoul security cooperation with Beijing in view?

Nishino: During his U.S. visit in April, Yoon reconfirmed that the South Korea-U.S. alliance has extended beyond the Korean Peninsula and developed into a “global comprehensive strategic alliance.” However, the main target of the U.S.-South Korea alliance is North Korea, and that point is unchanged. Meanwhile, the Yoon administration announced its Indo-Pacific strategy in late 2022 and is keen to play a more active role in the region. In an interview with Reuters, before flying to the U.S., Yoon said, “The Taiwan issue is not simply an issue between China and Taiwan but, like the issue of North Korea, it is a global issue,” provoking an angry response from Beijing. Yet, the Yoon administration summoned the Chinese ambassador to South Korea and made a protest against this. This attitude towards Beijing was previously unseen.

The Yoon administration’s policy goal toward China is to build mutually respecting relations. When President Moon made a state visit to China in December 2017, dinners with Chinese dignitaries were not adequately arranged, leading to criticism within South Korea that he got the cold shoulder. There is strong discontent in South Korea that China responds by looking down on it. While recognizing such public sentiment, the Yoon administration is trying to build a mutually respecting relationship with Beijing by maintaining an issue-by-issue stance. However, for South Korea, dealing with North Korea, rather than China, would continue to be the top priority in the Tokyo-Washington-Seoul cooperation.

Watanabe: To the U.S. eye, there is no doubt the strategic value of Japan and South Korea is rising since they accept U.S. military bases on the frontline with China. Viewed differently, Tokyo and Seoul have a leverage toward Washington. To make use of this leverage, rather than making demands to Washington through respective bilateral frameworks, it’s more effective to join hands in approaching Washington. For that, however, Tokyo and Seoul need high-level communication to function on a daily basis. It’s the same with Beijing. I hope to see progress in building the base to that end during Yoon’s term.

The Next Move in Japan-South Korea Relations


– What is necessary to develop the momentum of improved Japan-South Korea ties?

Nishino: For the last decade, dialogue between Tokyo and Seoul had been stalled or interrupted. They were fighting without even knowing the faces of their counterparts. So, first, restoring and reactivating the dialogue between the two governments is the top priority as well as a pragmatic issue. The agreement at the March summit also reflected this recognition. Fortunately, the Tokyo-Seoul security dialogue resumed for the first time in five years on April 17, and on May 3, Takeo Akiba, Secretary General of Japan’s National Security Secretariat visited Seoul and held economic security talks at the National Security Council (NSC) level. On May 2, a finance minister meeting was held for the first time in roughly seven years, so what remains is the resumption of the vice-ministerial level strategic dialogue. In terms of high-level exchange, building trust between lawmakers is also essential. In November 2022, Vice President Taro Aso of the ruling Liberal Democratic Party (LDP) met with Yoon in Seoul, spurring the move to improve bilateral ties. Going forward, it will be highly significant for politicians from the ruling and opposition parties to deepen their understanding of South Korea by restoring and building multilayered connections, with the Japan South Korea Cooperation Committee (Japan chairman: LDP Vice President Taro Aso) and Japan-Korea Parliamentarians’ Union (Japan chairman: former Prime Minister Yoshihide Suga) at the core. Since these are progressing smoothly now, I believe that specific cooperation programs in the fields such as security, economy, and global issues will be discussed and executed in a not-so-distant future.

– Next year, there will be a general election in South Korea and a presidential election in the U.S. Depending on the outcome, there may be a setback in the trilateral cooperation promoted by Kishida, Biden, and Yoon.

Nishino: South Korea’s general election is in April, so we cannot foresee the situation yet, but according to public polls, expectations are high for the opposition’s victory, and it seems like a tough election for the ruling party. Looking back on a year of the Yoon administration, regardless of the election results, I see him as unwavering in his resolution to improve relations with Japan. Yet, no matter how determined he is, he cannot advance if the domestic headwinds are too strong. Japan should be more active to push for the improvement of bilateral relations, which would ultimately provide backup for the Yoon administration.

The next presidential election is in 2027. If the candidate from the progressive camp wins, the solution on the forced labor issue could be overturned. Let me repeat that, we just have to accept it as the consequence of South Korea’s democratic dynamism. However, even with a change of administration, if the Japanese and Korean people come to believe that they are glad relations have improved and they do not want to slide back to the terrible decade, it could soften the reversal. I believe it is the task of the Japanese and South Korean governments to generate such public sentiment over the next four years.

Watanabe: The exact same could be said for the U.S. presidential election. At this point, the “Biden vs. Trump” is the most likely scenario for next year’s election, and there is a good chance Trump may win. If Trump becomes the president again, and Washington-Seoul or Tokyo-Washington-Seoul relations face a crisis, having a functioning Tokyo-Seoul channel would be a hedge against Washington. At least among U.S. security and military professionals, there exists a bipartisan consensus to emphasize Japan-South Korea cooperation to counter China. To let these professionals operate smoothly, it’s essential to accumulate achievements within the Tokyo-Seoul and Tokyo-Washington-Seoul framework over the next year or two.

This is a translation of the Japanese article published in vol. 79 (May/Jun. 2023) of the Gaiko (Diplomacy) magazine.

Junya Nishino is a Professor at Keio University. Earning a Ph.D. in political science from Yonsei University, he specializes in international politics of East Asia and contemporary Korean politics. His previous careers include a Special Assistant on Korean Politics at the Japanese Embassy in Seoul. He is the author/editor of Gekido no chosen hanto o yomitoku [Interpreting the Turbulent Korean Peninsula] and other books.

Tsuneo Watanabe is a senior fellow of the Sasakawa Peace Foundation. He earned an M.A. from the New School for Research in New York in 1995. He specializes in U.S. foreign and security policy. His previous careers include a senior fellow at the Center for Strategic & International Studies (CSIS), a senior fellow at the Mitsui Global Strategic Studies Institute, and a senior fellow at the Tokyo Foundation. He is the co-author/editor of Boei gaiko to ha nanika [What Is Defense Diplomacy] and other books.


Related Articles