A Perspective from the United States

The first ever stand-alone leader-level summit at Camp David between President Biden, Prime Minister Fumio Kishida of Japan, and President Yoon Suk-yeol of South Korea, marks the latest stage in a longstanding U.S. effort to tighten trilateral relations. The summit, however, was hardly inevitable. Although it rests upon existing trilateral architecture borne of previous efforts, it was the result of a particular combination of factors, some of which are highly contingent. These included: new leadership in Seoul wiling to improve ties with Tokyo despite the political risks this entailed; an increasingly complex and uncertain geopolitical environment within which the three countries are in greater (though hardly complete) strategic alignment regarding a worsening North Korean threat and strategic challenge posed by China; and the gradually expanding strategic apertures of both the US-Japan and US-ROK bilateral alliances, driven largely by Tokyo and Seoul’s steadily advancing national capacities and embrace of values-based relationships.

Nonetheless, the same factors paving the way for the summit, could complicate how sustained its outcomes turn out to be. For, despite their increasingly aligned strategic outlooks, the trilateral partners do not share the same (or the same degree of) strategic vulnerabilities. Additionally, a key geopolitical uncertainty that both Seoul and Tokyo face is the growing inconstancy of American leadership. In fact, Washington and its two Asian allies’ dogged effort to hold the summit is illustrative of their impulse to try and institutionalize deeper levels of cooperation before conditions change. Moreover, Seoul and Tokyo’s enhanced capacities, which make them such attractive partners for Washington and enabled the new level of trilateral cooperation evinced at Camp David, simultaneously allow them to hedge more effectively than ever before.

Unsurprisingly, Chinese officials have been highly critical of the Camp David summit. China’s foreign ministry spokesman Wang Wenbin warned that attempts to form “exclusive groups and cliques and to bring bloc confrontation into the Asia-Pacific region” were unpopular and would spark opposition.¹ Other reports indicated Beijing was watching closely for the formation of “a de facto Asian NATO.”² Similar messaging came from the main opposition Democratic Party of Korea. The party’s chief spokesperson, Rep. Kwon Chil-seung, said the commitment to consult announced at the summit “amounts to a de facto military alliance.”³ However, these warnings and characterizations—whether genuinely felt or instrumentally constructed—grossly overstate the case.

The trilateral summit at Camp David was, indeed, a historic development in relations between the three countries. The leaders reaffirmed existing understandings but also affirmed significant new ones. Yet they now must move from the difficult work of top-line statements to the even more challenging work of implementation. Although there is no doubt that the three leaders established a new baseline for trilateral relations, calling it a de facto alliance distorts reality.

From the moment it entered office and as part of its Indo-Pacific strategy, the Biden administration has clearly prioritized improving its respective bilateral relations with Japan and South Korea and, as a natural extension of that effort, trilateral relations. In doing so, the administration built upon the efforts of generations of US policymakers who, since the origins of the post-WWII US presence in the region, have seen Korea and Japan as inextricably connected and long sought to tighten that connection within a broader US strategic vision. Providing such a historical perspective is critical to assessing how we arrived at the Camp David summit, having a sense of what lies ahead, and understanding the limits of what is possible.

Going Back to Come Forward

As early as 1943, State Department planners began to envision a US-led postwar order in Asia, within which a reconstituted Japan was critical. And, given its proximity to the Japanese Islands, the Korean Peninsula was seen to be important for Japan’s security. Fearing a Soviet occupation of the entire peninsula, Washington agreed with Moscow to its temporary division at the 38th parallel until a political solution could be found to establish a unified and independent Korea. However, the ostensibly temporary division hardened under mutually incompatible US and Soviet Korea policies, the early onset of Cold War tensions, and intense and often violent machinations of different groups of Koreans favored by both superpowers within their respective occupation zones.⁴ Two diametrically opposed Korean states emerged.

As much as the fledging South Korea remained important to Japan’s security in the eyes of US officials, the U.S. military presence there was seen by some defense planners as a “strategic liability.”⁵ It was best withdrawn “as soon as possible with the minimum of bad effects.”⁶ Although undermining Tokyo’s security was considered one of the key potential bad effects US policymakers hoped to minimize, they calculated—incorrectly as it turned out—that South Korea’s security could be upheld by a fledgling United Nation’s collective security system rather than a formal bilateral security pact.

While North Korea’s invasion of the South and the Korean War proved this calculation tragically wrong, it catalyzed the US containment structure in the region (and beyond) and set in motion a series of firmer connections between the US presence and commitment to Tokyo and Seoul. US forces and bases in Japan were critical to the war effort. Japanese territory and facilities were used for training, staging, logistical and material support, and medical care for posted US and UN Sending States personnel. The United Nations Command (UNC) Headquarters was based in Tokyo for the duration of the war, and when UNC HQ was transferred to Seoul in 1957, UNC-Rear was established in Japan and remained critical in the event of another Korean conflict. Furthermore, although not generally advertised, Japanese personnel were involved in various elements of the conflict. Moreover, the war catalyzed Japan’s early rearmament by spurring the establishment of the US-equipped, 75,000-man National Police Reserve Force, the antecedent to Japan’s Self Defense Force (SDF). Finally, the war kick-started Japan’s economic recovery, with Prime Minister Yoshida calling it “a gift from the gods.”⁷

The Korean War also set in motion finalization of a peace treaty with Japan and the creation of the US-led hub-and-spokes alliance system in the region. Initially, US policymakers floated the idea of creating a “Pacific Pact,” a multilateral Asia-Pacific collective security architecture, instead of separate bilateral treaties. However, leaders in Japan, Australia, New Zealand, and the Philippines were cool to the idea; the latter three given their lingering animosity toward Tokyo and fears of Japanese rearmament, and Tokyo given its desire not to disrupt its economic recovery or the fragile coalition supporting a US-Japan bilateral alliance. Instead, in exchange for their agreeing to the San Francisco Peace Treaty, the US signed separate treaties with all four, to come into effect alongside the peace treaty with Japan, which formally ended WWII in the Pacific and the US occupation of Japan.⁸

When it came to South Korea, US officials also initially sought a collective security arrangement to guarantee Seoul’s security following the Korean War, namely, under the declaratory policy of the UN Sending States. However, for Rhee Syngman, the “Greater Sanctions Statement”—otherwise known as the Joint Policy Declaration or “Sixteen-Nation Declaration on Korea Issued at Washington”—was insufficient.⁹ Only a bilateral mutual defense treaty would suffice, which was signed on October 1, 1953, and entered into force on November 17, 1954. Yet, even as Washington finalized the bilateral treaty with Seoul and moved toward establishment of the multilateral Southeast Asian Treaty Organization (SEATO), US officials floated the idea of similarly linking Washington’s Northeast Asian allies into a single treaty arrangement; referred to as the Northeast Asian Treaty Organization (NEATO).¹⁰

On August 3, 1954, Secretary of State John Foster Dulles told a news conference the “United States is considering possibility of a mutual security pact covering Japan, Korea, and Nationalist China, but that this idea was still in preliminary stage of investigation and no decision has been made.” Dulles made clear that while thought had been given to “the possibility of such a treaty or possibly even of tying together in a single association Korea, Japan and Free China,” such discussions were on the level of “preliminary investigation and examination” and that no “decisions in that respect have been taken.”¹¹ The fact remained that neither South Korea nor Japan was interested in such an arrangement.

The Korean people and leadership in Seoul retained a deep animus toward Tokyo and jealously defended their recently secured bilateral pact with Washington. Tokyo, too, guarded its exclusive treaty with Washington, firmly opposed any expansion of its defense commitments given the “no war” clause in its constitution, and resented the implication that the “decision about such pact is one purely for United States to take, and that Japan as well as other countries will then acquiesce.”¹² The brief and ultimately desultory discussion about the possibility of NEATO was illustrative, however, of how US officials sought to tie together more seamlessly its various security commitments in the region. That impulse has remained consistent to this day.

Normalizing Seoul-Tokyo Ties & Recognizing Security Interdependencies

Without normalized relations between Tokyo and Seoul and the formal agreements by ROK and Japanese leaders, any potential linkage between the two bilateral treaties had little traction. Therefore, over the next fifteen years, US officials fitfully pushed both sides to normalize ties but to no avail. Deepening US involvement in Vietnam and the need to pass a greater burden to allies, though, reignited Washington’s effort to push for establishment of Seoul-Tokyo ties. The key enabling variable, however, was leadership change in Seoul and the arguments of key Japanese elites in Tokyo. In a nominally democratic South Korea, the normalization effort resulted in large public protests, but they did not prevent the June 1965 Treaty on Basic Relations Between Japan and the Republic of Korea.¹³

While the treaty hardly settled historical grievances (which would later be reopened within a consolidated South Korean democracy), it resulted in significant economic and business linkages between the two countries, contributed to Seoul’s industrial takeoff, helped establish the Japan-Korea Parliamentarians’ Union, and initiated regular meetings between respective foreign ministers starting in 1967. Such links did not result in formal bilateral security commitments or formation of a trilateral pact but did signal a greater alignment in strategic outlook and recognition of shared security interests, particularly as Tokyo and Seoul navigated growing doubts about the credibility of the US commitment. In 1968, both sides jointly declared “the security and prosperity of [South] Korea have important influence on that of Japan,” and, in the Nixon-Sato communique the following year, Prime Minister Sato acknowledged: “the security of the Republic of Korea was essential to Japan’s own.” South Korean leader, Park Chung-hee, quickly and enthusiastically embraced Sato’s statement.¹⁴

In the early 1970s, Tokyo backtracked from the “Korea clause” in the Nixon-Sato communiqué, fearing entrapment in a contingency on the Korean Peninsula, and adopted a more equidistant policy toward the two Koreas by stating in 1974 that peace and security “on the entire peninsula” was essential to Japanese security. However, ongoing doubts about US staying power—driven by the US withdrawal from Southeast Asia, fall of Saigon, and President Carter’s troop withdrawal policy from Korea—once again galvanized tighter Seoul-Tokyo ties and the first ever reciprocal exchanges of high-level Japanese and ROK defense and military officials, starting in the late 1970s.¹⁵

Although not formally institutionalized, these exchanges ultimately culminated in 1994 with the first ever visit by a ROK defense minister to Japan and an agreement to initiate regular exchanges of high-level defense officials. During the same period, political leaders also worked to strengthen ties. Encouraged by the Reagan administration, ROK dictator Chun Doo-hwan and Japanese Prime Minister Nakasone Yasuhiro held the first Korea-Japan summits in 1983 and 1984, helping set the course toward better relations.¹⁶ Nakasone also agreed to provide a large economic assistance package to help Seoul weather a severe recession and once again acknowledged Japan had a stake in the peace and security of the Korean Peninsula.¹⁷

Post-Cold War Transformation

Moving into the 1990s and post-Cold War era, ROK-Japan leader-level engagement deepened following high-level Japanese expressions of remorse that more openly acknowledged Japanese imperial war crimes, including the forced sexual slavery of Korean women and girls known as the “comfort women.” A watershed moment in Seoul-Tokyo ties was when President Kim Dae-jung and Prime Minister Obuchi Keizo released the Japan-Republic of Korea Joint Declaration in 1998, marking a commitment to reconfirm friendly relations and build a new, forward-looking partnership for the 21st century.¹⁸ It was in this context that Washington’s longstanding effort to foster trilateral relations entered a new phase, where a formal institutional architecture for trilateral cooperation began to emerge.

The Trilateral Coordination and Oversight Group (TCOG), launched in 1999, brought together US, ROK, and Japanese policymakers to work to align their policy approaches toward North Korea. It evolved over the next several years from a high-level dialogue into working-level discussions, ultimately resulting more in consultation than genuine policy coordination. While it ended in 2003, it laid the groundwork for later improvements, most notably the 2008 establishment of the Defense Trilateral Talks (DTT). The DTT is an assistant secretary-level meeting, during which defense officials from the three countries exchange assessments of the security environment on the Korean Peninsula and broader region and consult on ways to deepen US-Japan-ROK security cooperation. By the mid-2010s, such cooperation included various kinds of trilateral maritime security exercises and the first ever trilateral missile defense exercises in the face of an advancing North Korean nuclear and missile threat. ¹⁹

Nonetheless, info-sharing remained limited by ongoing challenges in Seoul-Tokyo relations, evinced by the last-second failure of Seoul and Tokyo to sign the General Security of Military Information Agreement (GSOMIA) in 2012. Despite strong US encouragement, Seoul postponed signing, given intense backlash from the South Koran public. Instead, all three signed a Trilateral Information Sharing Arrangement in 2014, which essentially amounted to a US-led hub-and-spokes intelligence sharing arrangement with the US serving as intermediary.²⁰ This changed in 2016 when Tokyo and Seoul finally signed the GSOMIA, after reaching a 2015 agreement on “comfort women.”²¹ Despite this progress, however, Seoul-Tokyo relations reached their nadir in 2018-2019 amidst mutual recriminations over various events, including: the Moon administration’s decision to effectively terminate the 2015 ROK-Japan agreement on “comfort women”; a radar-lock on incident between a ROK naval vessel and Japanese aircraft; the South Korean Supreme Court rulings that Japanese firms must compensate South Koreans over their force labor practices during the colonial period, Tokyo’s retaliatory economic measures on exports of key technology to South Korea; and Seoul’s threat to terminate the GSOMIA.²² Importantly, though, while the institutional architecture the trilateral partners had previously constructed did not function well during this period, it remained in place. When leadership and conditions changed in all three countries, that architecture was reenergized.

And, with the recent Camp David summit as a new baseline, the three countries appear ready to add new layers atop the existing structure. In addition to holding regular annual leader-level meetings, they have committed to holding annual meetings between their respective foreign ministers, defense ministers, commerce and industry ministers, and national security advisors. The three sides have held numerous such meetings in recent years, but institutionalizing regular, high-level consultations like these would mark a new level of coordination and commitment to the trilateral relationship. The same goes for the stated commitment to establish a multi-year trilateral exercise plan and improve cooperation on ballistic missile defense through enhanced, real-time data sharing.²³ Like consultations, such activities have already occurred, but if they are implemented and deepened as laid out at Camp David, it would add greater stickiness to trilateral cooperation moving forward.

To be clear, however, just as changed conditions and new leadership (particularly Yoon and his willingness to improve ties with Japan) provided the impetus to get to Camp David, conditions and leadership will change again. The objective now is to build what US National Security Advisor Jake Sullivan called “momentum and inertia,” to establish a higher bar so that when trilateral relations encounter rocky shoals—and they will—a more stable and layered architecture is in place to weather the storm.²⁴

Expanding the Strategic Aperture in the Indo-Pacific Era

Arguably, the most critical factors propelling trilateral relations since the end of the Cold War—and especially in the emergence of the Indo-Pacific Era—were developments in each bilateral alliance. Policymakers reframed and transformed the respective US-Japan and US-ROK alliances to help them better address a more complex international environment and division of labor in the 21st century. Starting with the 1996 Japan-US Joint Declaration on Security and 1997 Guidelines for Japan-US Defense Cooperation and followed later by the 2009 Joint vision for the alliance of the United States of America and the Republic of Korea, officials in Washington, Tokyo, and Seoul deliberately advanced the relationships to cooperate in areas extending beyond traditional security to encompass non-traditional security issues, political, economic, cultural, and people-to-people ties, not only on a bilateral basis but also a regional and global scale. Such transformation was driven in large part by Tokyo and Seoul’s steadily advancing national capacities and embrace of values-based relationships ²⁵

Whether it was the reframing of the US-Japan alliance as a robust alliance and global partnership or the US-ROK alliance as a comprehensive strategic alliance and later a global comprehensive strategic alliance policymakers expanded the strategic aperture of each alliance.²⁶ Alliance relations were increasingly defined by the diverse range of issues around which they cooperated but more importantly the shared values, principles, rules, and norms they upheld. Such discourse has become standard language in bilateral alliance statements as well as trilateral ones. Consequently, with the emergence of China as an object of strategic concern and a perceived threat in the United States, Japan, and South Korea, the three countries have increasingly aligned their strategic perspectives under their respective Indo-Pacific strategies and stressed the importance of tightening cooperation with like-minded countries.

Although Tokyo has been a bit more forward-leaning in naming China and specific Chinese behaviors, Seoul gradually followed suit. In successive official pronouncements, including US-ROK alliance leaders’ joint statements, a trilateral US-ROK-Japan leaders’ joint statement in Phnom Penh, and the ROK’s Strategy For a Free, Peaceful, and Prosperous Indo-Pacific Region, Yoon and his administration have reaffirmed a commitment to maintain peace and stability, lawful unimpeded commerce, and respect for international law including freedom of navigation and overflight and other lawful use of the sea, as far as the South China Sea and beyond. Additionally, in these various statements Yoon has reiterated “the importance of preserving peace and stability in the Taiwan Strait” as essential for security and prosperity in the Indo-Pacific region, for the broader international community, and, in the ROK’s Indo-Pacific strategy, for the “peace and stability of the Korean Peninsula.” Adopting this position on Taiwan in bilateral and trilateral statements and framing it increasingly in more expansive terms—and with direct reference to the Korean Peninsula—are unprecedented steps for the ROK. They represent a sea change in Seoul’s strategic signaling. And, for the first time ever, Seoul allowed specific mention of China and its activities in the region in the trilateral joint statement released at Camp David. ²⁷  

This does not, however, make the trilateral relationship a de facto alliance. The “Commitment to Consult” made at Camp David, whereby the three leaders committed to consult trilaterally in an expeditious manner and coordinate their responses to regional challenges, provocations, and threats affecting their collective interests and security, is undoubtedly a notable advancement in the trilateral relationship. However, half of the document states what it is not, namely, a replacement for each respective bilateral mutual defense treaty. Tokyo and Seoul will continue to jealously guard “the freedom to take all appropriate actions to uphold our security interests or sovereignty” as well as their exclusive alliance arrangements with Washington.²⁸

Ultimately, the trilateral relationship is strengthened by being nested within a broader array of multilateral partnerships, by a commitment to shared values, principles, rules, and norms, and by the fact that Tokyo and Seoul increasingly voice these values and principles on their own terms. Depending on the course of future events and shifts in the trajectory of American leadership, however, they may find it necessary to deepen cooperation with one another and other multilateral partners outside of a trilateral context and separate from their exclusive treaty relationships with Washington.