The US-Japan-ROK Trilateral in the Indo-Pacific Era: Strategic Alignment or Still in Flux?


After hitting rock bottom in the final years of the 2010s, prospects for the trilateral of the US-Japan-ROK have looked up in 2021, despite serious, lingering barriers. Four positive developments fall far short of a turnaround, but they have given momentum to this “virtual alliance” in just a few months. As we await the visit of President Moon Jae-in to Washington later in May, there is intensifying debate over whether this momentum will fizzle out—as have so many previous bursts of hope for relations between Tokyo and Seoul prodded by Washington—or continue to build in 2021-2022.

The positive developments of early 2021 are: the abrupt shift in US foreign policy in support of multilateralism in the Indo-Pacific region, as managed by experienced diplomats with a track record of active engagement with both Tokyo and Seoul to this end; the Seoul Central District Court ruling of April 21, which dismissed a damages lawsuit by former “comfort women,” applying (as Japan has long argued) sovereign immunity to the case; the removal of wedge-driving behavior by both North Korea and China, which exposed the differing responses in Seoul and Tokyo and made it harder for Washington to draw them together on a shared geostrategic agenda; and the accelerated pace of diplomacy that makes decisions more urgent as leaders are in a hurry to solidify their legacy. After Prime Minister Suga Yoshihide’s April summit success with President Joe Biden, Moon is anxious to showcase ROK-US relations in a positive light, including shaping the quest for trilateralism in a manner of his choosing.  

Below, I explore variations of trilateralism, indicating that Biden, Suga, and Moon lack a common vision. Yet Biden has moved vigorously, Suga has largely concurred, and, in stages in 2021, Moon has become more supportive. There is still a long way to go.

The Interim National Security Strategic Guidance released in early March describes the US objectives in a nutshell. To “strengthen our enduring advantages” and to “prevail in strategic competition with China or any other nation,” America will take a three-pronged approach: first, domestically, “defend and nurture the underlying sources of American strength, including our people, our economy, our national defense, and our democracy at home”; second, in the context of strategic competition, “promote a favorable distribution of power to deter and prevent adversaries from directly threatening the United States and our allies, inhibiting access to the global commons, or dominating key regions”; third, based on a position of strength, “lead and sustain a stable and open international system, underwritten by strong democratic alliances, partnerships, multilateral institutions and rules.”1 Deliberate in pursuit of these goals, Biden has invigorated diplomacy, first of all, with US allies, Japan and South Korea.

America will compete to protect and maintain the liberal internationalist order that it and its allies and partners built since World War II. This time, the main strategic competitor is not the Soviet Union, but China: “…the only competitor potentially capable of combining its economic, diplomatic, military and technological power to mount a sustained challenge to a stable and open international system.”2 Bordering China, the two, principal US allies in the Indo-Pacific, are facing more urgent diplomatic activity.

The Biden administration began its energetic diplomatic campaign, constrained by the COVID pandemic, with first priority on touching base with allies and major partners in Europe/NATO and the Indo-Pacific. Matt Pottinger, deputy White House national security adviser in the Trump administration, compared the situation to a race: “A favorite analogy in Beijing and Washington is that our countries are running a marathon, and only one contestant will win. It’s a fine metaphor, but it’s closer to the truth that we’re in a 400-meter dash that we have to win to qualify for the next leg of the marathon. If, over the next four years, we fail to set the right conditions, we could put ourselves on track to lose the race, although we might not realize it until several years after it’s too late to win.”4 Now, the Biden administration is running fast to create a firm base, a “position of strength,” to compete in the first leg of the marathon.

The Quad, a four-party consultative framework of the US, Japan, Australia, and India, promoted during the Trump years, became the first focus of Biden diplomacy. After the first ministerial in September 2019 during the Trump administration, it was upgraded to the first (virtual) summit held on March 12 this year with Biden, Suga, Scott Morrison, and Narendra Modi. A carefully-crafted Leaders’ Joint Statement, “The Spirit of the Quad,”5 avoided naming China, while outlining not only common principles and a vision for a “free, open, inclusive and resilient Indo-Pacific,” but also practical deliverables in critical areas—the COVID-19 vaccine partnership, a climate action working group, and a critical technology working group.6 The task ahead is how to develop this Quad and the so-called Quad Plus to serve as a connectivity platform for Indo-Pacific partnership.

The next focus of Biden’s Indo-Pacific diplomacy is revitalizing the US-Japan-ROK trilateral. Following the Quad summit, the 2+2 foreign and defense ministerial meetings in Tokyo and Seoul were held consecutively on March 16-18 as the first cabinet-level, in-person diplomacy by secretaries Blinken and Austin. The importance of the trilateral was confirmed in these meetings and at the April Biden-Suga summit. The Biden-Moon summit is due in late May. A trilateral summit on the sidelines of the G7 Plus London meeting in June is possible. Already on May 5 a trilateral foreign ministers meeting took place in London, but forging a common vision and agenda is still uncertain. 

If the Quad combines the US-Japan-Australia and US-Japan-India trilaterals, the US-Japan-ROK trilateral has a logic of its own, first and foremost, for maintaining security in Northeast Asia, above all, countering the North Korea nuclear threat, based on the US-Japan and US-ROK alliances. But, it has been increasingly challenged strategically and domestically—like a ship drifting without a compass. Japan-ROK relations as well as US-Japan-ROK trilateral cooperation have nose-dived, especially in 2018-2019. The General Security of Military Intelligence Agreement (GSOMIA) crisis of 2019, when the Moon government threatened to terminate the Japan-ROK arrangement as a countermeasure to the Abe government’s imposition of export control measures vis-a-vis South Korea, greatly frustrated the United States. The drift in recent years is due not only to domestic politics and political and legal issues over “history” (“comfort women” agreement, wartime Korean laborers issue) between Japan and ROK, but also to strategic estrangement not only on North Korea but also over the new strategic concept, the “Indo-Pacific.” The Trump administration changed the game vis-a-vis the strategic competition with China and the Indo-Pacific, and the Biden administration continues to push ahead with allies and partners. But as Gilbert Rozman noted, “[t]rilateral issues (among US, Japan, ROK) of 2016 are not those of 2021. […] If trilateralism fails, what hope remains for other forms of multilateralism in the Indo-Pacific?”7 

Can the US-Japan-Korea trilateral be tailored to the Indo-Pacific era? As the Trump administration responded to the GSOMIA crisis, the Biden administration has made known that the withering of the trilateral is not an option for the United States. Biden’s Indo-Pacific diplomacy has just started, but with many constraints, mainly in South Korea, the trilateral is still in flux. This article reviews the early months of Biden’s diplomacy regarding the US-Japan-ROK trilateral, then examines the different visions of the trilateral among the three parties, and lastly, looks at the prospects.

Getting the Message Across: The Two-Plus-Two in Tokyo and Seoul, and Summitry  

One goal of the Blinken-Austin 2+2 diplomacy with Tokyo and Seoul in March was to get the message across that the trilateral should be revitalized and Japan-Korea relations need to be mended. In a briefing with media outlets, Sung Kim, acting assistant secretary of state for East Asian and Pacific Affairs, said, “we are working to strengthen America’s relationships with our allies as well as relationships among them. And none are more important than Japan and the Republic of Korea. To highlight the vital importance of our three countries—the United States, Japan, and Korea—in promoting peace, security and prosperity in the Indo-Pacific region and beyond, Secretary of State Blinken and Secretary of Defense Austin will make the first overseas visit to Tokyo and Seoul.”7 David Helvey, acting assistant secretary for defense for Indo-Pacific Security Affairs added, the Blinken-Austin trip will “signal the importance of our alliance and partner relationships, which are a real force multiplier in advancing our shared interests in the United States commitment to a rules-based international order” including the Department of Defense’s “priority theater,” “the free and open Indo-Pacific region.” 8

The message was repeated in the State Department’s factsheets on US-Japan and US-ROK alliances released prior to the secretaries’ visits. In both factsheets, “Reaffirming the Unbreakable US-Japan Alliance” (March 14) and “Strengthening the Ironclad US-ROK Alliance” (March 17), an identical section on the trilateral, “Strengthening US-Japan-Republic of Korea Cooperation,” was inserted: “the Biden-Harris Administration is working to strengthen America’s relationships with our allies, and the relationships between those allies. No relationship is more important than that between Japan and the Republic of Korea” and that “a robust and effective trilateral relationship between the United States, the ROK and Japan is critical for our joint security and interests.”9

Secretaries Blinken and Austin endorsed the message in a joint, March 15 op-ed in The Washington Post: “The United States is now making a big push to revitalize our ties with friends and partners—both one-on-one relationships and in multilateral institutions—and to recommit to our shared goals, values and responsibilities. This week, in the first Cabinet-level overseas trip of the Biden-Harris Administration, we will bring that message to the Indo-Pacific region when we meet with our counterparts in Japan and the (sic) South Korea, two of our key allies.” They added, “[I]t is not only our one-to-one ties that are valuable. We’re also focused on revitalizing the relationship between and among our allies.”10 They noted that the trilateral cooperation goes beyond North Korea to the broader Indo-Pacific. “Our work with Japan and South Korea covers a vast range of issues that are critical to our security and prosperity. It is strongly in our interests for the Indo-Pacific region to be free and open, anchored by respect for human rights, democracy and the rule of law. This is the goal that Japan, South Korea and the United States share, and we will work together closely to achieve it.”11 

The secretaries’ message was finalized in the 2+2 documents in Tokyo and Seoul, reflecting Japan and South Korea’s positions respectively. In the US-Japan Security Consultative Committee (SCC) Joint Statement (March 16), Blinken and Austin, Foreign Minister Motegi Toshimitsu and Defense Minister Kishi Nobuo reaffirmed that “the US-Japan Alliance remains the cornerstone of peace, security, and prosperity in the Indo-Pacific region” and covered a wide range of issues including directly addressing concerns regarding China. The document noted that “trilateral cooperation among the United States, Japan and the Republic of Korea is critical for our shared security, peace and prosperity in the Indo-Pacific region.12 For the first time in an official US-Japan policy document, the trilateral was connected to the Indo-Pacific—a first for Japan too since it had never mentioned South Korea directly in the context of Indo-Pacific policy.   

In the US-ROK Joint Statement of the Foreign and Defense Ministerial Meeting (March 18) , Blinken and Austin, Foreign Minister Chung Euiyong and Defense Minister Suh Wook also acknowledged the importance of the US-Japan-ROK trilateral, but in a less assertive manner, avoiding direct linkage to the Indo-Pacific: “The Ministers and Secretaries affirmed the importance of ROK-US-Japan trilateral cooperation and pledged to continue promoting mutually-beneficial, forward looking cooperation to promote peace, security, and prosperity in the region.”13 While avoiding an inference to the Indo-Pacific in the trilateral context, in the bilateral context it acknowledged that the alliance is an Indo-Pacific alliance: “The Ministers and Secretaries reaffirmed that the ROK-US Alliance […] serves as the linchpin of peace, security, and prosperity on the Korean Peninsula and the Indo-Pacific region.”14

Acknowledgement at the ministerial level was followed by a trilateral national security advisors’ meeting on April 2 in Annapolis, with National Security Advisor Sullivan, National Security Secretariat Secretary General Kitamura Shigeru and National Security Office Director Suh Hoon. The press statement noted that the agenda was to “consult on the United States’ review of its North Korea policy” and “discuss issues of common concern including Indo-Pacific security,” and they “reaffirmed their steadfast commitment to working together to protect and advance their shared security goals.”15

At the US-Japan summit on April 16, Biden and Suga endorsed the “Free and Open Indo-Pacific” (FOIP) vision with a very broad agenda. The US-Japan-ROK trilateral was briefly mentioned, in the context of the Indo-Pacific, reaffirming the US-Japan 2+2 joint statement, though slightly revised. “Together, we will continue to work with allies and partners, including Australia and India through the Quad […] to build the free, open, accessible, diverse and thriving Indo-Pacific we all seek. We also support ASEAN’s unity and centrality in the Indo-Pacific as the ASEAN Outlook on the Indo-Pacific.”16 The US-Japan-ROK trilateral was acknowledged with minimal wording: “We also concurred that trilateral cooperation with the Republic of Korea is essential to our shared security and prosperity.”17 But Suga made clear in the press conference that trilateral cooperation was not only for North Korea but also for the Indo-Pacific: “Encountering North Korea, and for the peace and prosperity of the Indo-Pacific, both of us recognize that trilateral cooperation, including the ROK, has never been as important as today, and agreed to promote such collaboration.”18 This statement reiterated the US-Japan 2+2 Joint Statement. It is significant that Suga himself mentioned ROK as a partner in the context of the Indo-Pacific cooperation.  

Regarding the upcoming Biden-Moon summit, considering Moon’s reluctance on the trilateral, a verbal and written endorsement at the summit level would suffice. While hesitant on the Indo-Pacific, Moon did acknowledge the utility of the trilateral in a meeting with Blinken and Austin after the 2+2 in Seoul.19 A Biden-Suga-Moon meeting at the G7 Plus in London—akin to the trilateral at the Hague Nuclear Security summit in March 2016 with President Barack Obama, Prime Minister Abe Shinzo and President Park Geun-hye—would complete the first round of diplomacy, but the real task will lie ahead—whether the trilateral is functional not just in words but in actions.

Visions of the Trilateral Still in Flux: Trilateral Maximum, Minimum or Medium?

Biden has succeeded in getting the message across to US allies that the US-Japan-ROK trilateral should be revitalized, but on the “Indo-Pacific,” it is still halfway. Compared to the Quad or the other trilaterals (the US-Japan-Australia or US-Japan-India), the US-Japan-ROK trilateral is still in flux, and the three countries have yet to articulate a common vision and agenda. 

Three versions of the trilateral can be discerned: Trilateral Maximum (expanded version), Trilateral Medium (moderate version), and Trilateral Minimum (limited version) or “Trilateralism Light” as coined by Rozman.20 The US (Biden administration) advocates the expanded version, Japan (Suga administration) is in the middle supporting the moderate version, and the ROK (the Moon administration) leans toward the limited version but fluctuates. Will the three countries be able to strategically align on the Indo-Pacific and find convergence in the direction of the trilateral?

The US View: Trilateral Maximum

For the United States, trilateral cooperation is an enabler for the two alliances in Northeast Asia to function effectively. As Blinken and Austin said, “Our alliances are what our military calls ‘force multipliers.’ We’re able to achieve far more with them than we could without them.”21 They are also a mechanism for alliance management, diplomatically and militarily, to keep the two allies, Japan and the ROK, together. As for the scope of trilateral cooperation, North Korea is the core issue, but the US aims for trilateral cooperation beyond North Korea to Northeast Asia (China, Russia), and now more broadly in the “Indo-Pacific” not only in defense but also in the economic sphere, as well as on global issues. Undergirding these interests is the foundation of shared values. This is the Trilateral Maximum.

The Biden administration approached the US-Japan-ROK trilateral as one of the top priorities in Indo-Pacific diplomacy. Top-level diplomacy reflects the priority it places on the bilateral alliances and the trilateral. The Biden team understands that Japan-Korea relations need fixing. It has intervened because the US needs trilateral cooperation not only on the North Korea issue but also on the broader Indo-Pacific region to achieve the goals outlined in the Interim Strategic Guidance. A proponent of the Trilateral Maximum is Blinken, who draws on his experience in the Obama years as deputy secretary of state in promoting trilateral cooperation as part of the Rebalance strategy.22 This time, his task is to refashion the trilateral in the Indo-Pacific context.  

In their joint op-ed in March, Blinken and Austin defined a broad agenda for the trilateral, from defense, economy, and democratic values, to North Korea, the Indo-Pacific, and the world: “Our work with Japan and South Korea covers a vast range of issues that are critical to our security and prosperity—and to the world’s. Our diplomats and defense leaders strategize together on how to confront shared threats such as North Korea’s nuclear weapons and ballistic missile programs. We stand together in support of democratic values and will do so strongly wherever they are challenged. We collaborate on the full spectrum of new global security issues, including climate change, cybersecurity, and health security and pandemic preparedness. And our governments and private sectors are intent on strengthening economic ties between our countries that benefit workers and businesses. All that work is tied directly to the safety, well-being and economic security of the American people […] There’s another reason we’ve made this part of the world the site of our first in-person travel as secretary of state and secretary of defense. The Indo-Pacific region is increasingly the center of global geopolitics. It is home to billions of the world’s people, several established and rising powers, and five of America’s treaty allies. Plus, a great deal of the world’s trade travels through its sea lanes. It is strongly in our interests for the Indo-Pacific region to be free and open, anchored by respect for human rights, democracy and the rule of law. This is a goal that Japan, South Korea and the United States share, and we will work together closely to achieve it.”23

State Department factsheets for the two alliances reiterated the Blinken-Austin line. Identical messages, which envisaged the expanded version of trilateral cooperation, were inserted: “The United States continues to promote expanded US-Japan-ROK cooperation (“US-ROK-Japan cooperation” in the US-ROK factsheet) to tackle COVID-19 and combat climate change, as well as reinvigorate trilateral cooperation on a broad range of global issues, including the denuclearization of North Korea […] A robust and effective trilateral relationship between and among the United States, the ROK, and Japan is critical for our joint security and interests in defending freedom and democracy, upholding human rights, championing women’s empowerment, combating climate change, promoting regional and global peace, security, and the rule of law in the Indo-Pacific and across the globe.”24

Compared to what preceded, the Biden administration faces a stalemated but less acrimonious Japan-ROK relationship, and an increased necessity for strategic alignment regarding the Indo-Pacific, not only in defense, but on the economy and shared values.

The Japanese View: Trilateral Medium

Japan supports the US view of the expanded version of the US-Japan-ROK trilateral, but it takes a more moderate view, i.e., Trilateral Medium. Due to South Korean sensitivities regarding cooperation with Japan on security issues, Japan is hesitant to define a full agenda like the US, though it sees that as a desired goal, and will support the trilateral agenda with the US, especially trilateral security cooperation as an extension of the US-Japan alliance, a “force multiplier” as suggested by Blinken and Austin. For Japan, the US is the only formal treaty ally obligated to mutual defense. The same goes for South Korea and the US. Japan and South Korea are not formal military allies, but “virtual allies” in the US alliance network.25 Japan does not seek a formal “military alliance” among US-ROK-Japan but will pursue practical cooperation where possible.

The Japan National Security Strategy (J-NSS) (2013) of the second Abe administration says, “The Japan-US Alliance is the cornerstone of Japan’s security. Likewise, for the US, the Alliance has served as the core of its alliance network with countries in the region, including the Republic of Korea (ROK), Australia, Thailand, and the Philippines,” adding “trilateral cooperation among Japan, the US and the ROK is a key framework in realizing peace and stability in East Asia. Japan will strengthen this trilateral framework, including in cooperation on North Korean nuclear and missile issues.”26 Thus, Japan sees trilateral cooperation as an extension of the US-Japan alliance, with the strategic objective of “peace and stability in East Asia,” which includes the North Korea issue but also beyond.

Despite the rocky relationship due to incidents between the two militaries (the SDF flag and radar lock-on incidents in 2018), the official position on trilateral cooperation remained steady. The National Defense Program Guidelines (December 2018), even as it shifted the strategic concept from Asia-Pacific to the “Free and Open Indo-Pacific,” noted that Japan will “continue to strengthen trilateral cooperation among Japan, the ROK and the United States to maintain peace and stability in the region.”27 Although Japan and South Korea are the “missing link” in the Indo-Pacific scheme, Japan has been reluctant to acknowledge South Korea as a partner in the Indo-Pacific.28 This is due to poor bilateral ties and South Korea’s hesitance in identifying with the Indo-Pacific or the FOIP vision. Policy experts in Japan say, while there are political difficulties, Japan does not mean to exclude South Korea. 29

Japan continues to support trilateral cooperation but mainly in the context of Northeast Asia, with a focus on the North Korea issue. In the aftermath of the GSOMIA crisis, Defense Minister Kono Taro commented that “Japan-US and Japan-ROK bilateral cooperation and Japan-US-ROK trilateral cooperation are important amid the severe security environment in East Asia.”30 After Japan-ROK dialogue resumed, albeit briefly, Abe reconfirmed the importance of South Korea as a partner which “shares fundamental values and strategic interests” in a policy speech to the Japanese Diet in January 2020:  “As the security environment in Northeast Asia becomes increasingly severe, our diplomacy with neighboring countries becomes of extreme importance. The Republic of Korea is naturally our most important neighbor, which shares fundamental values and strategic interests with Japan. It is for exactly that reason that we sincerely expect the ROK to uphold promises made between our countries and build future-oriented Japan-ROK relations.”31

After another year of deadlock, Suga retreated to mentioning South Korea only as “a highly important neighboring country” in his first policy speech in the Diet in October 2020: “The Republic of Korea (ROK) is a highly important neighboring country. In order to restore sound Japan-ROK relations, we strongly urge the ROK, based on Japan’s principled positions, to take appropriate actions.”32 But a small hint of strategic alignment can be discerned; in the US-Japan 2+2, Japan acknowledged US-Japan-ROK trilateral cooperation in the context of “Indo-Pacific” security for the first time. At the summit with Biden, Suga agreed that trilateral cooperation is “essential” for “shared security and prosperity,” which signals cooperation not only in defense and security, but also “prosperity,” the economic realm. The trilateral is important to deal with the North Korea issue as well as for peace and prosperity in the Indo-Pacific. Thus, Japan is treading between the expanded version and limited version of the trilateral. It grasps the strategic meaning of the trilateral and is willing to go along with US policy, but politically, treading with caution, due to the state of relations with South Korea.

The ROK View: Trilateral Minimum, but fluctuating

The ROK is most reluctant on US-Japan-ROK trilateral cooperation. Conservatives, such as the Lee Myung-bak administration, who focus on strengthening the US-ROK alliance, have tried to upgrade the trilateral in alignment with the US and Japan.33 This continued into the Park Geun-hye administration, which resulted in the signing of the Japan-ROK GSOMIA in late 2016, though focused only on North Korea. But with the advent of the progressives, trilateral cooperation has retreated again to “Trilateralism Light.” Progressives tend to lean toward strategic autonomy more than alliance, so they favor Trilateral Minimum. Moderate progressives understand the importance of the US alliance and have been pragmatic about security cooperation with Japan. The Kim Dae-jung administration agreed to starting an official ROK-Japan security and defense dialogue in 1998, and acknowledged the role of the US alliance on both sides.34 As for a trilateral, the Trilateral Coordination and Oversight Group (TCOG) was launched in 1999, institutionalizing policy coordination on North Korea.

However reluctantly, the Moon administration has acknowledged trilateral cooperation. Within the administration, pragmatists tend to advance US alliance and security cooperation with Japan, cautiously, while not antagonizing China, and “minjok” (Korean nationalist) ideologues put engagement with North Korea first and, in parallel, confrontation with Japan increases. The pragmatists now see the utility of trilateral cooperation to show support for the US alliance; however, it is not firmly undergirded by strategic foundations aligned with the US and Japan and becomes opportunistic or transactional depending on the interests at hand. As a result, the Moon administration’s commitment to trilateral cooperation has fluctuated, as has its position on ROK-Japan relations.

In 2017, amidst the North Korean nuclear and missile crisis, Moon started with a pragmatic stance, prioritizing the alliance: “I will endeavor to address the security crisis promptly […] If needed, I will immediately fly to Washington. I will also visit Beijing and Tokyo and even Pyongyang under the right circumstances. […] I remain committed to doing all I can for the settlement of peace on the Korean Peninsula. The ROK-US alliance will be further strengthened. In the meantime, I will have serious discussions with the United States and China for the resolution of issues related to THAAD.”35

As declared in his inaugural speech, Moon, while treating the alliance as a main pillar, pursued what he calls “cooperative diplomacy.” With China, he tried to resolve the THAAD (Terminal High Altitude Area Defense) issue sanctions by supporting the so-called “three noes” for security,36 which restrain South Korea’s own security policy through the US-ROK alliance as well as US-ROK-Japan trilateral cooperation.   
Moon also committed to US-Japan-ROK trilateral cooperation as he welcomed Trump to Seoul in November 2017. The Joint Press Release “reiterated their intent to boost trilateral security cooperation with Japan for enhanced deterrence and defense against North Korea’s nuclear and missile threats. The two leaders committed to continue trilateral exercises on missile warning and anti-submarine warfare, as well as to expand information sharing and to enhance joint response capabilities against the North Korean threat.”37 In a follow-up interview, Moon stated, “for South Korea to respond to North Korea’s nuclear and missile threats, cooperation with not only the US, but also with Japan, have become crucial.” However, he added, “the reason for the enhanced trilateral cooperation between these nations is to respond to North Korea’s provocations, and I don’t believe it is desirable to develop trilateral cooperation into a military alliance,”38 a minimum version of trilateral cooperation limited to North Korea.

In 2018-19, as peace initiatives and US-North Korea talks progressed and Japan-Korea relations deteriorated, mention of trilateral security cooperation practically disappeared. The ROK National Security Strategy (December 2018) did not mention it.39 As history issues flared, the ROK threatened to terminate GSOMIA in response to Japan’s export control measures. The US intervened strongly to maintain the US-Japan-ROK trilateral, and at the same time, promoted strategic alignment on the Indo-Pacific policy, with which the ROK New Southern Policy became linked strategy, focusing on economic cooperation, though the ROK avoided using the term “Indo-Pacific” for its own policy.40 

In 2021, the Moon administration made another turnabout in response to the Biden administration’s policy, aligning closer with the United States on alliances, trilateral cooperation, and the Indo-Pacific, while not overtly antagonizing China, and seeking US support for the Korean peace process and engagement with North Korea. In his New Year’s Address, Moon stated that, “the Government will strengthen the ROK-US alliance in step with the launch of the Biden Administration. At the same time, we will make our final effort to achieve a major breakthrough in the stalled North Korea-US talks and inter-Korean dialogue.”41 On February 4, in the first official phone call with Biden, Moon still hesitated to refer to the “Indo-Pacific” related to the US-ROK alliance, tweeting “President Biden and I pledged to upgrade the ROK-US alliance, an alliance that is anchored in shared values. We will always stand together as we work for peace on the Korean peninsula and tackle global challenges.”42 The White House deferred to the Blue House and noted that “the United States-ROK alliance […] is the linchpin for peace and prosperity in Northeast Asia.”43

Yet, in their first phone call (February11), the former security adviser and newly appointed minister of foreign affairs Chung Eui-yong and Blinken concurred on an expanded version of the US-ROK alliance and, by extension, US-ROK-Japan trilateral cooperation which included the Korean Peninsula, Northeast Asia, the Indo-Pacific (while the ROK avoided the term “FOIP”), and global issues. In the State Department readout, Blinken “pledged full partnership to enhance the strength of the US-ROK Alliance, which is the linchpin of peace, security, and prosperity for Northeast Asia, a free and open Indo-Pacific region, and across the world” and “highlighted the importance of continued US-Republic of Korea-Japan cooperation.”44 In the ROK MOFA statement, both parties affirmed that the “ROK-US Alliance is the linchpin of peace, security and prosperity for Northeast Asia, the Indo-Pacific region, and across the world. They agreed to further develop the Alliance to address global issues and contribute to the promotion of shared values,” and Chung agreed on “the importance of continued ROK-US-Japan cooperation.”45

On March 1, Independence Movement Day, Moon sent a conciliatory message regarding Korea-Japan relations and renewed his commitment to the US-ROK-Japan trilateral partnership: “Korea and Japan have become very important neighbors” and that “[b]ilateral cooperation will not only benefit our two countries above all else but also facilitate stability and common prosperity in Northeast Asia and the trilateral Korea-United States-Japan partnership.”46 Moon still prefers a limited version of the trilateral, focused on North Korea and Northeast Asia, but he acknowledged the trilateral at this juncture in light of the Biden push on alliances and the trilateral.   

The US-ROK 2+2 on March 17 redefined the alliance as an Indo-Pacific alliance, which was a necessary step in upgrading the alliance in the Indo-Pacific era. The US-Japan-ROK trilateral was still treated in vague terms, being managed carefully, leaving room for further development. 

Conclusion: The Way Ahead

Can the US-Japan-Korea trilateral be tailored to the Indo-Pacific era? Biden’s Indo-Pacific diplomacy and strategic intervention to revive the trilateral is pushing Japan and ROK to cooperate. Managing “history” issues will not be easy, but the two countries—the missing link in the Indo-Pacific scheme—are being nudged to explore how to cooperate strategically on a broader scale. 

As a proponent of the US-Japan-ROK trilateral, Blinken talked about the need for a vision in 2016: “We have to articulate a vision for long-term trilateral cooperation that proves its centrality to the defense of our shared interests and preservation of our shared ideals.”47 He focused on: 1) strategic cooperation on the North Korea issue; 2) building constructive relationships in Asia; and 3) trilateral cooperation that is global in scope—an expanded version of the trilateral.

A common vision has been lacking in the US-Japan-ROK trilateral for years, but the US is articulating one for the Indo-Pacific era. Next generation leaders also support a broader agenda.48 It is incumbent upon Japan and the ROK as US allies to find practical ways to re-engage strategically and promote cooperation with the United States and with each other. North Korea will be one of the top priorities, but another would be the broader strategic agenda in the Indo-Pacific.49 A cautious process is foreseen, but, so far, the political momentum is being maintained as the trilateral is renewed and refashioned for the future.

* Sections of this article are adapted from the author’s paper presented at the Korean Association of International Studies (KAIS) International Seminar, “The Biden Administration and Korea-US Relations,” (Panel 3 The Biden Administration’s Korea Strategy and Korea-US Relations), February 26, 2021.

1. The White House, Renewing America’s Advantages: Interim National Security Strategic Guidance (hereafter Interim Strategic Guidance), March 3, 2021, pp. 9, 20.

2. Ibid., p. 8.

3. Matt Pottinger, “Beijing Targets American Business,” The Wall Street Journal, March 26, 2021.

4. The White House, “The Quad Leaders’ Joint Statement; ‘The Spirit of the Quad,’” March 12, 2021.

5. Ibid.

6. Gilbert Rozman, “Challenges to Biden’s pursuit of trilateralism,” The Asan Forum, December 30, 2020, pp. 4, 17. See also Gilbert Rozman, ed., Asia’s Alliance Triangle: US-Japan-South Korea Relations at a Tumultuous Time (New York: Palgrave Macmillan, 2015).

7. US Department of State, “Briefing with Acting Assistant Secretary of State for East Asian and Pacific Affairs Sung Kim and Acting Assistant Secretary of Defense for Indo-Pacific Security Affairs David F. Helvey on the Secretaries’ Upcoming Trip to Japan and Republic of Korea, Special Briefing,” March 12, 2021.

8. Ibid.

9. US Department of State, “Fact Sheet: Reaffirming the Unbreakable US-Japan Alliance,” March 14, 2021, “Fact Sheet: Strengthening the Ironclad US-ROK Alliance,” March 17, 2021.

10. Antony J. Blinken and Lloyd J. Austin, III, “Opinion: America’s partnerships are ‘force multipliers’ in the world,” The Washington Post, March 15, 2021.

11. Ibid.

12. The White House, “US-Japan Joint Press Statement,” March 16, 2021.

13. US Department of State, “Joint Statement of the 2021 Republic of Korea–United States Foreign and Defense Ministerial Meeting (“2+2”),” March 18, 2021.

14. Ibid.

15. The White House, “United States-Japan-Republic of Korea Trilateral National Security Advisors’ Press Statement,” April 2, 2021. 

16. The White House, “US-Japan Joint Leaders’ Statement: ‘US-Japan Global Partnership for a New Era,’” April 16, 2021.

17. Ibid.

18. The White House, “Remarks by President Biden and Prime Minister Suga of Japan at Press Conference,” April 16, 2021.

19. The White House, “United States-Japan-Republic of Korea Trilateral National Security Advisors’ Press Statement,” April 2, 2021.

20. Rozman used “Trilateralism Light” to explain the Moon administration’s stance as of December 2020. “As Biden is still in transition before a policy review, Moon is seeking to preempt his prospective approach with Trilateralism Light, limiting both any reconciliation with Japan and a broad range of trilateralism that could alienate North Korea and China.” “Challenges to Biden’s pursuit of trilateralism,” p. 17.

21. Antony J. Blinken and Lloyd J. Austin, III, “Opinion.”

22. Sakata Yasuyo, “Beikoku no Ajia Taiheiyo Rebalance Seisaku to Beikan-domei: 21-seiki ‘Senryaku Domei’ no Mittsu no Kadai,” Kokusai Anzen Hosho, Vol. 44, No. 1 (June 2016), pp. 49-63.

23. Antony J. Blinken and Lloyd J. Austin, III, “Opinion.”

24. US Department of State, Fact sheet, “Reaffirming the Unbreakable US-Japan Alliance,” March 14, 2021; “Strengthening the Ironclad US-ROK Alliance,” March 17, 2021.

25. Yasuyo Sakata, “ROK-Japan Defense Security Cooperation in the US-ROK-Japan ‘virtual alliance’: Evolution and Prospects,” New Asia. Vol. 24, No. 3 (Autumn 2017), pp. 118-155.

26. Japan National Security Council, National Security Strategy, December 17, 2013, pp. 20, 23.

27. Japan National Security Council, National Defense Program Guidelines for FY 2019 and beyond, December 18, 2018, p.16.

28. Regarding the reassessment of South Korea as a security partner in Japan’s Indo-Pacific shift, see Yasuyo Sakata, “Chapter 2: Changing Japan-ROK Relations Implications for US-ROK-Japan Trilateral Strategic Cooperation: A Japanese perspective,” in Scott Harold,, The US-Japan Alliance and Rapid Change on the Korean Peninsula: Proceedings from a Pair of Conferences (Santa Monica: RAND, March 2021), pp.14-16.

29. For example, Kanehara Nobukatsu, former assistant chief cabinet secretary to Abe and deputy secretary-general of the National Security Secretariat, said in an interview with Nikkei, that Japan needs to engage South Korea on the “Quad-Plus Alpha” grouping. Nikkei Shimbun, April 20, 2021. Japanese experts on economic and tech security, such as Murayama Yuzo, advocate that Japan should engage emerging digital tech middle powers such as South Korea and Taiwan. PHP Geo-Technology Senryaku Kenkyukai, Haitek Haken Kyoso jidai no Nihon no Sinro, PHP Research Institute (Tokyo), April 2020, p. 57.

30. Japan Ministry of Defense, Defense White Paper 2020, p. 359.

31. Cabinet Office, “Policy Speech by the Prime Minister to the 201st Session of the Diet,” January 20, 2020.

32. Cabinet Office, “Policy Speech by the Prime Minister to the 203rd Session of the Diet,” October 28, 2020.

33. See Sakata Yasuyo, “Global Korea to Beikan Doumei: Lee Myung-bak Seiken jidai no doumei henkaku,” in Okonogi Masao and Nishino Junya, eds., Chosen hanto no Chitsujo Saihen (Tokyo: Keio University Press, 2013), pp. 27-56.

34. “The two leaders welcomed the security dialogue as well as the defense exchanges at various levels between the two countries and decided to further strengthen them. The leaders also shared the view on the importance of both countries to steadfastly maintain their security arrangements with the United States while at the same time further strengthen efforts on multilateral dialogue for the peace and stability of the Asia-Pacific region.” Ministry of Foreign Affairs (Japan), “The Japan-ROK Joint Declaration,” October 8, 1998.

35. The Blue House, “Inaugural Address to the Nation by President Moon Jae-in,” May 10, 2017.

36. The “three noes” are no additional US THAAD system deployments, no participation in a US-led regional missile defense system, and no development of US-Japan-ROK trilateral cooperation into a formal military alliance. South Korean officials have said these principles are not a promise to China, but a mere affirmation of ROK policy, leaving room for maneuver, but according to Nikkei Asia columnist Minegishi Hiroshi, they were worked out with China over three months and constrain policy to China. H. Minegishi, “Moon Jae-in’s visit to US tinged by promises to China,” Nikkei Asia, April 30, 2021.

37. The White House, “Joint Press Release by the US-ROK: President Donald Trump’s State Visit to the Republic of Korea,” November 8, 2017.

38. “Channel News Asia Conversation with South Korea’s President Moon Jae-in,” November 9, 2017, Channel News Asia.

39. The Moon Jae-in administration’s National Security Strategy, Office of the National Security of the Republic of Korea, Cheongwadae, December 2018.

40. US Embassy, Seoul, “President Trump and President Moon Reaffirm United States’ and Republic of Korea’s Ironclad Alliance,” July 2, 2019; “Fact Sheet: ROK and the United States Working Together to Promote Cooperation between the New Southern Policy and the Indo-Pacific Strategy,” November 2, 2019 (Bangkok); US State Department, “Joint Statement on the 4th ROK-US Senior Economic Dialogue,” November 6, 2019 (Seoul), See also Choe Wongi, “Why South Korea wants to tie in with ASEAN,” ASEAN FOCUS, No. 6 (December 2019). NSP was upgraded to “New Southern Policy Plus,” announced by the ROK government in November 2020 at the 21st ROK-ASEAN summit.

41. The Blue House, “New Year’s Address by President Moon Jae-in,” January 11, 2021.

42. “Presidents Moon and Biden hold the first phone summit,” February 4, 2021.

43. The White House, “Readout of President Joseph R. Biden, Jr. Call with President Moon Jae-in of the Republic of Korea,” February 3, 2021.

44. US Department of State, “Secretary Blinken’s Call with ROK Foreign Minister Chung,” February 11, 2021.

45. Ministry of Foreign Affairs (ROK), “Minister of Foreign Affairs Holds Telephone Conversation with US Secretary of State,” February 12, 2021.

46. The Blue House, “Address by President Moon Jae-in on 102nd March First Independence Movement Day,” March 1, 2021.

47. US Embassy, Seoul, “Deputy Secretary Antony Blinken Remarks on US-Japan-R.O.K. Trilateral Relationship,” March 29, 2016 at the Brookings Institution.

48. For a recent report, see Reinvesting in US-Japan-Republic of Korea Strategic Relations: A Practical Trilateral Agenda, Policy Recommendations from an Emerging Leaders working group, Organized by The National Committee on American Foreign Policy, January 2021.

49. See Yasuyo Sakata, “Japan-South Korea Relations and the Biden Factor,” Asia Unbound, Council on Foreign Relations, December 21, 2020.

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