Relocating Trilateralism in a Broader Regional Architecture
A South Korean Perspective

Yul Sohn
March 25, 2016

Yul Sohn, Dean of the Graduate School of International Studies and Professor of International and Japanese Political Economy at Yonsei University in Seoul, reflects on the U.S.-Japan-ROK trilateral relationship from a South Korean perspective.

Ever since the Trilateral Coordination and Oversight Group (TCOG) was launched in 1999 as a means of institutionalizing the process of policy coordination on North Korean nuclear development, various forms of trilateral cooperation have developed and evolved over the decades. But Japan and the Republic of Korea (ROK), two legs of the triangle, remain mired in historical animosity with complex roots that hinder strategic and operational coordination of alliance policy and capabilities. Due to a landmark agreement reached between South Korea and Japan in December 2015—which may help resolve the “comfort women” issue that has been the biggest obstacle to improving bilateral ties—trilateralism is likely to be promoted. North Korea’s latest nuclear test and its ongoing long-range missile programs pose a grave security threat to not only South Korea and Japan but also the United States. As the three countries quickly move to coordinate policies around harsh condemnation and more sanctions, their partnership finds the added opportunity to move from separate bilateral alliances into a closer, trilateral arrangement that would improve their security posture vis-à-vis North Korea.

Eyes are on China to see whether this test will finally compel a change in its policy toward North Korea. While the key to success is well-coordinated three-way pressure from the United States, the ROK, and Japan, such pressure must be combined with active cooperation from China, and Beijing is reluctant to push too hard on North Korea. Because the survival of the North Korean regime remains a strategic asset to China, Beijing will most likely avoid applying pressure that could lead to regime collapse.

This indicates South Korea’s strategic difficulties: it needs to strengthen the U.S.-Japan-ROK relationship by improving ties with Japan while expanding its own networks with China in order to gradually alter China’s strategy toward North Korea. In fact, the ROK seeks a path that strengthens trilateral security ties while ensuring that China does not feel excluded. Simultaneously, it pursues a path that promotes multilayered cooperative networks with China while hedging against Chinese predation by courting U.S. and Japanese engagement. Conceptually, this means that South Korea seeks to weave trilateral networks together with China-Korea networks.

Historical Background

In South Korea, U.S.-Japan-ROK trilateral cooperation has often been tainted by its Cold War legacy. During the Cold War era, this triangle was charged with maintaining deterrence against the Communist bloc. The confrontation of the southern triangle (the United States, Japan, and the ROK) with the northern triangle (Russia, China, and North Korea) was accompanied by an ideological rivalry. The policy of virtual alliance with a former enemy and colonizer (Japan), which was engineered by South Korea’s militarist, authoritarian leader, Chun Doo-hwan, was justified by Cold War logic. But mounting criticism from South Korean civil society focused on the fact that this Cold War alliance forced the country to the front line of dangerous war planning.

The tainted image of trilateralism was improved by the North Korean nuclear crisis. Cooperation evolved as all three nations attempted to coordinate their respective policies for dealing with North Korea. In 1999 the TCOG was formed as an opportunity for Washington to involve Seoul and Tokyo in the U.S. policymaking process and avoid sending Pyongyang mixed signals. But the process weakened over time as conflicting views and interests over the most appropriate policies toward North Korea strained the relationships among the three nations. For example, Seoul became more willing than Washington and Tokyo to engage Pyongyang as the Kim Dae-jung government pursued its Sunshine Policy toward the North. The TCOG was practically replaced by the six-party talks as the key multilateral forum to address the North Korean nuclear problem. Trilateral cooperation only operated within the broader, multilateral context of the six-party talks, and it took on a new role as an informal caucus among the three countries within this framework. Often South Korea played the role of mediator between North Korea, on the one side, and the United States and Japan, on the other. The Roh Moo-hyun government regarded trilateralism as a spoiler rather than a catalyst for denuclearizing North Korea.

Renewed Enthusiasm

Renewed enthusiasm for trilateral cooperation came from the military transformation process led by the George W. Bush administration during the 2000s. In order to adapt to multilayered challenges, ranging from terrorism to major wars, the administration set out to transform U.S. forces into globally mobile units. If forces stationed in Japan and South Korea were to assume broader missions and roles, the two alliances would need to evolve as well. Against the backdrop of this changing security environment for the United States, trilateral cooperation resurfaced as a priority. Should tensions arise on the Korean Peninsula while U.S. Forces Korea (USFK) were in operation elsewhere, or should a crisis occur, a more integrated approach would be needed to coordinate regional strategies and combine available resources among the three countries.

In contrast with the transformation of the U.S.-Japan alliance, in which the two sides agreed on expanding their common strategic objectives to include responding to terrorism and proliferation and carefully watching China’s rise, Seoul and Washington made little progress on redefining the role of USFK for a changing regional security environment. South Korea under Roh was reluctant to accept the concept of strategic flexibility, whereby U.S. forces could relocate to other parts of the world as needed. Roh was wary of potentially using the U.S.-ROK alliance to balance China. While advocating a multilateral approach to Northeast Asian security, he even suggested that the ROK should be less dependent on the United States and more self-reliant in defending itself. Consequently, the alliance relationship was strained.

The Obama administration’s “rebalance to Asia” centers on the United States’ ability to reinvigorate and leverage traditional alliances for a stronger and enhanced role in the region. Following the economic recession and fiscal retrenchment restraining U.S. military expenditures, the United States asked Japan and South Korea to share increased financial burdens and new operational roles and missions in alliance management. The Lee Myung-bak government responded positively. It quickly shifted policy course by taking a confrontational approach to North Korea and recuperating the ROK’s strained relationship with the United States. The administration also responded to U.S. efforts to reinvigorate trilateralism.

By December 2010, ministers from the three countries had agreed on a joint statement. The agreement went beyond mutual bilateral responsibilities to deal effectively with common security threats, including from North Korea, and underscored the importance of strengthening trilateral cooperation on economic, political, and security issues. The agreement further sought to find ways to address a long list of global challenges, including terrorism, proliferation of weapons of mass destruction, piracy, climate change, epidemics, and energy security, while promoting green growth, freedom of navigation, and maritime security.

Admittedly, these are lofty strategic goals. South Korea, even under a pro-U.S., pro-Japanese leadership, had been reluctant to engage in any meaningful military cooperation with Japan, given the politically sensitive nature of their relationship. For example, in June 2010, South Korean leaders attempted to sign a general security of military information agreement that would provide a legal framework for sharing classified military data between the two countries, but the move backfired because of the popular discontent with the government’s secretive handling of the issue.

The deeply rooted animosity between South Korea and Japan has recurred over the decades and negatively affects trilateral cooperation, which is perceived as the cornerstone of the U.S. strategy for dealing with North Korea.  [1] Since the election of Shinzo Abe and Park Geun-hye in December 2012 as the new heads of Japan and South Korea, respectively, the political divide between the countries has not only reached its worst mark but also produced significant structural opportunities for China to drive a wedge in the trilateral alliance in a way that has brought Seoul closer to Beijing while distancing it from Tokyo. The result is that South Korea and China have aligned to denounce Abe’s stance on Japan’s historical legacies of colonialism and war, which the Japanese press has branded the “Korea-China alliance against Japan on history.”

Washington has managed to improve the troubled relationship, intervening at several pivotal points during the past two years to help bring Abe and Park closer together. In March 2014, Obama persuaded the two to sit together in a trilateral setting on the sidelines of the Nuclear Security Summit in The Hague, which was the first top-level meeting between South Korea and Japan since Park and Abe took office. Soon after, the United States successfully persuaded a reluctant ROK to join talks on a trilateral arrangement for sharing military information, to participate in trilateral defense ministerial meetings, and to hold a bilateral summit meeting. This trend continued when the three countries signed a memorandum of understanding on sharing intelligence on North Korean issues in December 2014.

Will Japan-ROK Relations Improve?

Nonetheless, there exist formidable obstacles to improving trilateral relations. First, historical tensions and territorial issues not only are the main sources of mistrust between Japan and South Korea but also have helped shape the identity of each nation. In a 2015 joint public opinion survey conducted by the East Asia Institute of South Korea and Genron NPO of Japan, 57% of the South Korean public characterized Japan as militaristic, while 34% said it was statist.  [2] On the other hand, 56% of the Japanese public views South Korea as nationalistic and 34% as statist. Despite the fact that both South Korea and Japan are allies of the United States, a large majority of South Korean respondents indicated a high-level threat perception toward Japan. Likewise, another recent joint public opinion survey conducted by the Chicago Council on Global Affairs, the East Asia Institute, Genron NPO, and Horizon demonstrates the striking fact that more than half of the South Korean respondents (54%) believe that there is a possibility of military conflict between Japan and South Korea.   [3]

Very recent efforts by Park and Abe led to a breakthrough that may open the road to improve the bilateral relationship after both sides agreed to “finally and irreversibly” resolve the long-standing issue of Korean comfort women. It is too early to tell, however, if they succeeded in removing the biggest obstacle to the beginning of a new era of bilateral relations. Abe expressed sincere apologies and remorse to the comfort women while also conceding that Japanese military authorities played a role in the sexual enslavement. Tokyo offered to set up a fund of one billion yen ($83 million), paid directly by the government, and to provide care for the comfort women.

Despite these developments, South Korean citizens continue to protest against the Japanese government for refusing to admit legal responsibility for these crimes. There also remains strong opposition to the removal of the statue of a girl symbolizing the comfort women that is installed in front of the Japanese embassy in Seoul. Along with the opposition party and NGOs, the general public turned against the resolution. On January 8, a joint survey conducted by the Korean Broadcasting System, the national public broadcaster in South Korea, and Gallup Korea revealed that 26% of South Koreans support the agreement, while 56% oppose it. Moreover, 72% of respondents say that Japan refuses to apologize fully, while only 19% were satisfied by the apology. An overwhelming percentage of the public (72%) is opposed to relocating the comfort woman statue.   [4]

Beyond the comfort women issue, there remain many other history issues, including controversies over Japanese textbooks, wartime forced labor, visits to Yasukuni Shrine, and territorial disputes over the Dokdo/Takeshima Islands. Clearly, the landmark agreement between the two countries does not end the historical disputes. The structural constraints are resilient and remain unresolved.

South Korea’s Middle-Power Activism

In a broader sense, there is an encouraging development toward trilateralism in terms of “middle-power diplomacy.” South Korea has aspired to play a middle-power role in international affairs. As the country’s assets have expanded, there have been increasing calls for South Korea to adopt a proactive foreign policy role commensurate with its material power. At the same time, it is re-evaluating the validity of a security posture based solely on the bilateral alliance with the United States. South Korea has aspired to play a middle-power role that encompasses three dimensions. The first is to increase the degree of connectedness with actors from whom the country gathers information and with whom it can foster coalitions. The second is to adopt a mediating or bridging role. South Korea can use its leverage over other states and increase its bargaining power through links to partners that are otherwise weakly connected. Finally, South Korea aims to help establish principles, norms, and rules in international institutions.

There is a strong need for South Korea to apply its middle-power role to help shape the regional architecture. Tensions have developed over the years as the United States and China compete over regional leadership, with Japan firmly aligned with the United States. South Korea, however, has attempted to take a different approach by playing a mediating role and developing friendly relations with both great powers. It maintains a long-standing alliance with the United States (and partially with Japan), while recently crafting an amicable relationship with China. But South Korea has not yet succeeded in this role because both China and the United States support the initiatives of middle powers only to the extent that these initiatives serve their respective interests. In addition, as stated earlier, the soured ROK-Japan relationship has hampered South Korea’s efforts to play a mediating role because a middle power needs to be well connected.

The U.S.-Japan-ROK trilateral relationship should be relocated. The objective of South Korea’s middle-power diplomacy is to deepen the trilateral cooperation network and locate it within a broader regional architecture that includes China. The next step for South Korea to realize its middle-power role is twofold. First, South Korea needs to adopt a long-term approach that develops its reputation as a middle power on regional economic and nontraditional security issues while expanding its engagement on global issues to include global finance, cybersecurity, climate change, and human rights. In doing so, the country would be able to establish its identity as a contributor to regional and global stability and prosperity.

The second step is deepening partnerships with China. Beijing is concerned that measures to enhance U.S.-Japan-ROK trilateral military cooperation against North Korea would eventually work as a means to pressure China, while strong sanctions would cause regime collapse, leading to the United States gaining extended influence over the Korean Peninsula. Unless South Korea alleviates such concerns, its efforts toward North Korean denuclearization will be limited. The country needs to clearly present its strategic purposes: its North Korea policy targets denuclearization while pursuing peaceful coexistence and gradual and nonviolent unification with the North. South Korea also needs to stress that trilateral military cooperation against North Korea has little to do with U.S.-China strategic competition but instead aims at ensuring the stability and peace of the peninsula. Seoul should take a long-term perspective. It should work to cultivate diverse networks with China and persuade Beijing that South Korea’s strategic goals are not incompatible with those of China; rather, in the long run both countries can evolve in harmony.


[1] Joel S. Wit, Daniel B. Poneman, and Robert L. Gallucci, Going Critical: The First North Korean Nuclear Crisis (Washington, D.C.: Brookings Institution Press, 2004).

[2] “2015 Han-il gugmin sanghoinsig josa” [2015 Survey on Mutual National Recognition of Korea and Japan], East Asia Institute and Genron NPO, 2015,

[3] Karl Friedhoff and Dina Smeltz, “Strong Alliances, Divided Publics: Public Opinion in the United States, Japan, South Korea, and China,” Chicago Council on Global Affairs and East Asia Institute, October 2015.

[4] “Hanguk Gaelleob deilli opinieon” [Gallup Korea Daily Opinion], Gallup Korea, no. 193, January 8, 2016.

Note: This essay partially draws on Yul Sohn, “Searching for a New Identity: South Korea’s Middle Power Diplomacy,” Policy Brief, December 2015,

Yul Sohn is Dean of the Graduate School of International Studies and Professor of International and Japanese Political Economy at Yonsei University in Seoul.

This brief reflects the South Korean perspectives on the U.S.-Japan-ROK trilateral relationship and was produced with support from the Korea Foundation and the Japan–United States Friendship Commission.