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Abhishek Sharma, “US-South Korea-Japan Trilateral: Challenges to an Enduring Security Cooperation,” Issue Brief No. 826, Observer Research Foundation, August 2025.
Shifting geopolitical alignments are causing transformations in diplomatic relations, including the United States’ (US) ties with Europe, and with Russia. The US is increasingly focusing on the Indo-Pacific, guided by its ‘Pivot to Asia’ strategy to counter China, its primary adversary. In particular, the US is paying greater attention to the Northeast Asia sub-region in the Indo-Pacific, which it considers important in deterring Chinese military activities and a possible future conflict. While the US has consistently recognised the region as vital for its military domination in the Indo-Pacific, its importance has become even more critical considering the region’s strategic value for China.
Recognising this, the Biden administration focused on strengthening the US’s partnership with its Northeast Asian allies. With President Donald Trump again at the helm of affairs and amidst the changing regional power dynamics between the US and China, this brief analyses the importance of the trilateral alliance.
The Trilateral Security Cooperation (TSC) between the US, South Korea, and Japan has been in place starting from the administration of Bill Clinton (1993-2001) to that of Joe Biden (2021-2024). However, each country’s level of engagement, as well as their investment in the partnership’s upkeep, has varied based on their strategic rationale. For the US, the trilateral has acted as an institutional mechanism that has protected its interests. For South Korea, continuous engagement with the TSC has been dependent on the nature of the incumbent government in Seoul: for progressive leaders, the TSC is like a strategic insurance policy; and for conservatives, it is a strategic necessity. Japan views the trilateral as more of a strategic investment: a necessary mechanism to strengthen regional norms and a rules-based order.
Over the years, the TSC has functioned well when compared to other platforms in the Indo-Pacific. It arguably achieved its potential during the Biden administration due to a sharp convergence in strategic language and threat perception between the three countries. Such a convergence is reflected in each country’s strategic policy documents—the US's Indo-Pacific Strategy, the South Korea’s Indo-Pacific Strategy, and Japan’s Indo-Pacific Vision.
A consistent, core objective of the trilateral format is to coordinate policies on the North Korean nuclear threat. However, the legacy was first disrupted by Trump when he started direct negotiations with the North Korean leader, Kim Jong Un in 2018, putting US interests first. Under the Biden Administration, the TSC became more institutionalised and flexible, watching the North Korean threat and also other regional issues linked with China. The seriousness of the Chinese threat led to a further deepening and expansion of the existing framework through sustained diplomatic, political, and economic investment. This elevated the TSC's importance for Japan and South Korea, and became even more critical for the US. The growing North Korean nuclear challenge and the Chinese military and technological threat incentivised the US to make the TSC a top priority. This commitment was visible when Anthony Blinken, former US Secretary of State, paid 21 visits to the region during his tenure.[1]
Unlike the US, South Korea has approached the TSC from a different strategic viewpoint, primarily shaped by the incumbent government’s foreign policy approach—this has oscillated between support, neglect, and opposition. For instance, progressive leaders like Roh Moo-hyun viewed the TSC as a spoiler for the administration’s denuclearisation goal, and President Moon Jae-in approached it with scepticism. Conservative leaders like Park Geun-hye attached great importance to the trilateral, and Yoon Suk Yeol saw it as a catalyst for his Global Pivotal State Vision.[2] Under Yoon Suk Yeol, the government revised its foreign policy to align closely with the US’s strategic aims.
Similarly, since the late 1990s, all Japanese governments have seen the TSC as an important part of their foreign policy, aimed at strengthening the regional deterrence security architecture against the North Korean nuclear weapons programme. It would help establish a broad framework in the Indo-Pacific region and strengthen the existing international rules-based order.
The highest trilateral meeting between the US, South Korea, and Japan can be traced to the meeting in November 1994 between then-President Clinton and his counterparts, Prime Minister Tomiichi Murayama and President Kim Young-sam. The meeting took place after the signing of the Agreed Framework (AF) in October 1994 on the sidelines of the Asia-Pacific Economic Cooperation (APEC) Summit.[3] The press briefing released after the meeting emphasised closer cooperation between the three countries, stating, “(T)here was also a clear consensus that we need to continue to consult and cooperate closely as we proceed with implementation of the [Agreed Framework] agreement.”[4] President Kim Young-sam emphasised that “cooperation among our three countries is needed to support the idea that North Korea will faithfully implement the agreement.”
Under the AF, the objective was to establish the Korean Peninsula Energy Development Organization (KEDO), which mandated it “to deliver interim energy until the first [Light Water Reactor] LWR was completed.”[5] Following the APEC meeting, senior bureaucrats facilitated bilateral cooperation between the three countries, which would later be formulated as an innovative framework. In 1999, under President Clinton, a Trilateral Coordination and Oversight Group (TCOG) was set up to facilitate cooperation on the AF. Its mandate was “to ensure closer coordination of policy toward North Korea with our [US’s] two principal allies in Northeast Asia [Japan and South Korea].”[6]
As George W. Bush became president, he continued the negotiations with North Korea under the AF. He simultaneously engaged Japan and South Korea through the TCOG mechanism to deliberate on the North Korean threat. However, in 2003, after the AF broke down, the negotiations moved to a multilateral diplomacy framework known as the Six-Party Talks (SPT),[a] which became a better platform for all parties. As the SPT progressed, Bush's focus turned to North Korea's nuclear weapons programme. In a press conference acknowledging the importance of SPT, he stated, “Multilateral diplomacy is the best way to peacefully solve an issue such as the nuclearization or the weaponization or the desire to have a nuclear weapon program by the North Koreans.”[7]
This showed his preference for SPT—a sentiment that would be supported by the Roh Moo-hyun administration. In a statement released by the US State Department, President Roh observed, “We both [Presidents Bush and Roh] agreed on the positive outlook for the six-party talks. We believe that this progress is very meaningful.”[8] The trilateral mechanism became less relevant when the US and South Korea invested in SPT. Despite the SPT, however, the three continued informal consultations on the issue.[9] It stopped when the SPT arrangement collapsed at the end of his administration in 2008, paving the way for then US President Barack Obama to start his initiative.[10]
The collapse of SPT coincided with Obama’s first tenure (2008-2012), which led to the resumption of the TSC mechanism. Two other developments happened in parallel: Lee Myung-bak becoming South Korean president and Obama announcing his “rebalance towards the Asia-Pacific” strategy.[11] Both these developments catalysed the TSC in the initial years. Lee's conservative presidency after a decade-long democratic rule in South Korea favoured closer military ties with the US and Japan, which led to strong cooperation against North Korea. Similarly, Obama’s rebalance strategy aimed to strengthen cooperation with allies and partners in the region, which gave the TSC a nudge.
In December 2010, the joint statement from a trilateral ministerial meeting reiterated the call “to intensify policy coordination and strategic dialogue among the three countries and reflects the need for greater trilateral cooperation in addressing enduring and emerging challenges.”[12] North Korea’s continued aggressive and provocative behaviour during the first Obama administration only gave it more weight. This started with the Taepodong-2 long-range missile and nuclear test in April and May 2009,[13] and the sinking of the South Korean naval ship Cheonan in March 2010, which resulted in the death of 46 Korean soldiers,[14] followed by the shelling of the Yeonpyeong Island in November 2010, killing four civilians. However, the domestic sentiment in South Korea still did not favour strong defence ties with Japan, given the historical legacy issues between the two countries. Accompanying this was what analysts would describe as Lee’s political adventurism in the second half of his administration.[15]
Nonetheless, President Obama established an important mechanism in 2008 that helped create a foundation of a trilateral defence mechanism for consultation—the Defence Trilateral Talks (DTT), which convened its latest 15th edition in 2024.[16] During Obama’s second term, the TSC got a push through the establishment of a trilateral ministerial mechanism in April 2015, which focused on enhancing cooperation between the three countries. This trilateral framework’s objective was “to intensify policy coordination and strategic dialogue among the three countries, and reflects the need for greater trilateral cooperation in addressing existing and emerging challenges.”[17] The initiative was made possible by Obama’s political leadership, which stressed improving South Korean and Japanese ties, a move that was critical for the US’s rebalance strategy.[18]
The new conservative leaders, like Park Geun-hye and Shinzo Abe, enabled Obama’s goal of forging a common cause by lending their political support to the TSC. This effort became particularly more vigorous with North Korea’s fifth nuclear test on 9 September 2016. After the test, the three countries held a trilateral ministerial meeting on 18 September 2016 “to ensure that the three countries remain(ed) in close coordination in the wake of North Korea’s second nuclear test in eight months” and “explored ways to work together to ensure that all countries fully and effectively implement all their obligations and commitments under UN Security Council Resolution 2270.”[19] A series of resolutions were then passed in the UNSC (UN Security Council), such as UNSC Resolutions 2321, 2371, 2375, and 2379,[20] which sought to constrain the DPRK’s capability. The united political stance of the three compelled even China and Russia to lend their support to the UNSC Resolutions.
The improving bilateral ties between South Korea and Japan coincided with Shinzo Abe and Park Geun-hye’s foreign policy initiatives. Abe's larger vision of popularising the Indo-Pacific concept attempted to form a larger democratic alliance in the Indo-Pacific region. Similarly, Park Geun-hye sought more support for her Northeast Asia Peace and Cooperative Initiative (NAPCI) initiative, aimed at “accumulating conventions of dialogue and identifying areas of cooperation … as well as enlarging the scope of cooperation in traditional security-related matters.”[21],[22]
Under Abe and Park, a breakthrough happened with the first trilateral vice-ministerial meeting in April 2015, followed by the second in January 2016.[23] This easing of bilateral ties between South Korea and Japan enabled greater trilateral cooperation. For the first time, the three countries conducted ballistic missile defence and anti-submarine warfare exercises, first in June 2016[24] and again in April 2017.[25] On the bilateral front, the signing of the agreement in December 2015 to resolve the issue of the “comfort women”,[26] followed by the signing of the General Security of Military Information Agreement (GSOMIA) in December 2016 to share military-sensitive information with Japan, and a joint naval exercise in April 2017, helped bridge the weak link in the trilateral relationship.[27] The US welcomed this agreement, reiterating the importance of bilateral cooperation for strengthening the TSC, stating: “(W)e face many challenges in the region and around the world that require the collective efforts of our three countries.”[28]
The cooperation between the three countries under the Obama administration expanded for the first time. While the primary concern was the imminent threat of North Korea, other issues were pursued, such as cybersecurity, energy security, global health, and space policy.[29] The aim was to utilise existing mechanisms “to expand our cooperation and establish patterns of trilateral partnership that will bear valuable results for our publics, the region, and the world beyond.”[30]
The year 2017 brought many changes to the TSC, as leaderships changed in Washington, D.C. and Seoul. Trump became the US president, and Moon Jae-in took office in South Korea.[31] During Trump’s presidency, the TSC mechanism was shaped by two vital developments: Trump’s independent North Korea policy and weak ties with allies, South Korea and Japan. Unlike Obama and Biden, Trump’s tenure stands apart due to his overarching role, which, to an extent, was also driving the direction of the TSC.
On the North Korean issue, the first year started with Trump’s exchange of undiplomatic statements with the regime. In his second year, Trump adopted the maximum pressure strategy, through military threats and harsher sanctions, which created pressure and paved the way for prolonged nuclear negotiations with Kim Jong Un, resulting in three bilateral summits.[32] This thaw in US-North Korea ties coincided with the easing of inter-Korean relations through three summits between Kim Jong Un and Moon Jae-in, which resulted in the Panmunjom Declaration on 18 September 2019. Both these developments marked a downgrading of the North Korean threat and its de-hyphenation from the TSC framework. Some announcements from both sides contributed to further de-hyphenation, such as Kim Jong Un’s decision to discontinue nuclear and ICBM tests, and the US and South Korean decision to suspend joint military exercises. Nonetheless, the negotiations with the US failed in October 2019 in Sweden, and ties with South Korea were severed in June 2020 as missile tests and military exercises resumed.[33]
Meanwhile, Trump was consumed by the trade war with China, which even entangled the US’s allies and further derailed the trilateral cooperation. Additionally, bilateral issues related to burden-sharing, such as special measures agreements and the defence budget, became points of discussion.[34]
While Trump pursued his policies, relations between South Korea and Japan worsened, becoming hostage to their legacy issues. For instance, in the first year of his administration, Moon Jae-in discontinued the comfort women and the GSOMIA agreements with Japan.[35],[36] Closer to 2020, Japan’s decision to enforce export controls of key ingredients, such as chemicals used in semiconductor industries, and remove South Korea from the trusted list of partners, contributed to the spiralling of relations.[37] Therefore, while 2017 started on a good note, 2018 and 2019 were low points. Analysts attributed this deterioration to the alleviating “domestic pressures at the cost of bilateral cooperation; with the [South Korea] ROK pursuing satisfactory solutions for victims of WWII outside of standing agreements with the GOJ, and Japan working to evolve into a more active regional role while neglecting earnest efforts at bilateral cooperation.”[38] This coincided with the changing South Korean foreign policy, which preferred resolving issues with North Korea rather than fuelling tensions—a change from the preceding administration. Moon’s approach later became a bone of contention between him and Abe, as stated in Moon Jae-in’s memoir, where he observed, “Abe did not pay attention at all to South Korea’s position of putting priority on easing tensions.”[39] Therefore, the gains earned during the second Obama Administration—starting with incremental expansion of the trilateral agenda—went back to focusing on the North Korea issue due to the failing ties between South Korea and Japan.
Nonetheless, trilateral meetings continued to take place, primarily driven by the continued threat from North Korean missile launches and the leadership provided by the US. For instance, the first trilateral leaders’ meeting under Trump took place on 6 July 2017, on the sidelines of the G20 Summit in Hamburg, where the three leaders “committed to continue advancing trilateral security cooperation in the face of the threat posed by the DPRK.”[40] On 22 September 2017, Trump hosted another trilateral meeting in New York during the UN General Assembly, where “(t)hey agreed to mobilize all available means to maximize pressure on North Korea and call on all other nations to do the same.”[41] This indicated a high level of strategic pragmatism in South Korea, as it continued the trilateral security and defence cooperation to enhance deterrence against the North Korean threat, irrespective of the status of bilateral ties between Seoul and Tokyo.[42] President Moon Jae-in identified “future-oriented cooperation”[43] as the mainstay of South Korea’s ties with Japan, echoing the country’s reasoning. Some observers called Moon Jae-in’s public dealings with Japan symbolic of his dual personality: a statesman and an activist.[44]
Shortly after becoming President-elect in November 2020, Joe Biden began his administration’s ‘Diplomacy First’ approach[45] to consolidate the US’s alliances and expand partnerships in the Indo-Pacific, particularly with South Korea and Japan. Biden’s objective was to build on the 10 years of Obama’s ‘Pivot to Asia-Pacific’ strategy (Pivot 1). The Biden administration reinvented Pivot 1 as Pivot 2, reformulating Obama's policy with an Indo-Pacific focus.[46] Pivot 1 focused on increasing military presence and trade pacts like the Trans-Pacific Partnerships (TPP). Pivot 2 concentrated on strengthening existing military alliances and partnerships through the Quadrilateral Security Dialogue (Quad), Australia-UK-US (AUKUS), and TSP, as well as geoeconomic platforms like the Indo-Pacific Economic Framework for Prosperity (IPEF).[47]
The strategists behind the Pivot 1 agenda were also pushing Pivot 2: Secretary of State Anthony Blinken; Deputy Secretary of State (DSC) Wendy Sherman; and Kurt Campbell, Deputy Assistant to the President and Coordinator on Indo-Pacific affairs on the National Security Council. Campbell had earlier played a leading role in shaping US policy towards the Indo-Pacific region, including restarting the US-South Korea-Japan trilateral. As the Assistant Secretary of State for East Asian and Pacific Affairs during the first Obama administration, he played a key role as architect of the Pivot to Asia-Pacific strategy.[48] Therefore, the continuation of Obama’s policy helped strengthen the foundation of the TSC and build on the earlier initiatives that became dormant.
The elements of Biden’s foreign policy emphasising the importance of the TSC found their place in primary strategic documents like the Indo-Pacific Strategy (IPS) released in February 2022 and the National Security Strategy (NSS) of October 2022. For instance, the NSS stated, “(A) free and open Indo-Pacific can only be achieved if we build collective capacity” with the five regional treaty alliances and closest partners.[49] Similarly, at the core of the IPS was to operationalise and “expand US-Japan-ROK Cooperation.”[50] This was part of the US’s latticework arrangement “with intertwined, overlapping and interlocking engagements,” which included the Quad, AUKUS, and the US-South Korea-Japan trilateral in the Indo-Pacific region (see Figure 1). Campbell reiterated the importance of the TSC as part of the US’s IPS during the Asan Forum 2024. He said that “cooperation is at heart” of Biden’s IPS and that “bilateral and trilateral bonds with the Republic of Korea and Japan will define the future of Asia and grow our collective proprietary and security”, including dealing with the North Korea challenge.[51]
Figure 1: The US’s Interlocking Engagements in the Indo-Pacific
Source: Narupat Rattanakit[52]
The third critical element was the expansion of the trilateral agenda, as shown in Table 1.
Table 1. Trilateral Security Cooperation Framework
| Initiative | Trilateral Framework |
| Defence Cooperation | Memorandum of Cooperation on the Trilateral Security Cooperation Framework[53]
|
| Space, and Critical and Emerging Technology |
|
| Trade and Commerce |
|
| Women, Youth, and Climate Change |
|
| Health |
|
Source: Author’s own, using various sources[56],[57],[58]
Under Biden, two vital changes occurred. First, an attempt was made to expand the cooperation beyond the North Korea challenge, including critical issues like economic security, space security, cyber cooperation, and climate change. The second was the expansion and alignment of threat perception between the three members, including the evolving risk from China and Russia. This was possible primarily due to President Yoon, under whose leadership South Korean foreign policy adopted strategic clarity. This led to improved South Korea-Japan ties and closer cooperation with the US on regional challenges. Additionally, the Biden administration sustained diplomatic efforts to expand cooperation, and Japan’s political leadership reciprocated towards South Korea by contributing to the TSC’s success and institutionalisation.
The three elements mentioned above contributed to the TSC's success, which further helped in its institutionalisation. The first attempt took place in July 2024 when a Memorandum of Cooperation on the Trilateral Security Cooperation Framework (TSCF) was signed between the defence ministries of the three countries. The TSCF's aim was to institutionalise the “trilateral security cooperation among defense authorities, including senior-level policy consultations, information sharing, trilateral exercises, and defense exchange cooperation.”[59]
This step was a significant “attempt to insulate the partnership from potential domestic political shifts in any of the three countries, aiming to ensure long-term strategic continuity regardless of leadership changes.”[60] This became more evident as soon as Donald Trump was re-elected as the 47th President of the US. The institutionalisation of the trilateral was announced on the sidelines of the APEC Summit in Peru on 15 November. The Joint Statement mentions the establishment of a Trilateral Secretariat that will “ensure that the work we do together further aligns our objectives and actions to make the Indo-Pacific a thriving, connected, resilient, stable, and secure region.”[61] The inaugural Japan-US-South Korea Trilateral Coordinating Secretariat Meeting occurred in Seoul following the announcement.[62]
Trump’s re-election has clouded the future of the trilateral, with the concerns pertaining to both its security and economic aspects. South Korea and Japan surmise that Trump would be more focused on economic issues rather than the security threat from North Korea. At the same time, some analysts predict that Trump 2.0 will adopt a Nixon Doctrine,[b] delegating more security responsibility to its allies as it focuses on countering China.[63] US allies remain sceptical about Trump's ‘Peace through Strength’ approach, which they perceive as a move towards a non-involvement posture similar to his promise to end the Ukraine-Russia war and the conflict in the Middle East.
Already, there are conversations about South Korea pursuing its nuclear weapons programme to enhance deterrence against North Korea as doubts increase over the US’s extended nuclear umbrella.[64] Trump's remarks have not helped. US-based Politico has reported that Trump “is considering a plan to let the Democratic People’s Republic of Korea [North Korea] keep its nuclear weapons and offer its regime financial incentives to stop making new bombs.”[65] If this were to happen, it would not only create fissures in its alliance with South Korea but also halt the TSC entirely.
While uncertainty looms regarding Trump, the political environment in South Korea and Japan is also not appearing conducive to the continuation of TSC. Political rumblings have hit Seoul, starting with the imposition of martial law on 3 December, followed by the impeachment of President Yoon Suk Yeol and Acting President and Former Prime Minister Han Duck-soo. Since the beginning of the impeachment process, public support for the party and the president has plummeted, raising questions about his and the party’s political future.
The former ruling People Power Party (PPP) supported the TSC, which it asserts even in post-martial law episodes. For instance, after Yoon’s impeachment, the acting President of the forum, Prime Minister Han, had a conversation with both his counterparts in the US and Japan. In his brief call with President Biden, he reiterated that “our (his) government will carry out our diplomatic and security policies without disruption and work to ensure that the South Korea-U.S. alliance continues to be maintained and developed without wavering.”[66] Similarly, in his first conversation with Ishiba, Han noted, “We will work to maintain and further strengthen the frameworks for bilateral Japan-ROK and trilateral Japan-U.S.-ROK cooperation.”[67] Contrary to popular perception, the opposition Democratic Party of Korea (DPK) has taken a nuanced position on trilateralism, supporting cooperation with the US and Japan. Lee Jae Myung, the opposition leader, in a media interview said, “Washington doesn’t need to ‘excessively’ or ‘unnecessarily’ worry about the strength of the alliance under a Democratic administration.”[68] While the trilateral may continue moving forward, the degree of cooperation remains highly uncertain. Much of its success under the DPK will depend on the state of ties between Korea and Japan. Based on the precedent under Lee Jae Myung, the party will continue investing in the trilateral but would be hesitant to broaden the scope of cooperation, unlike the conservatives.
While Lee’s views towards the trilateral are positive, his stance on other issues, such as China, North Korea, and Japan, will make the cooperation challenging. For example, while discussing the North Korea issue in an interview, Lee Jae Myung expressed his support for Trump's effort to restart dialogue with North Korea, re-negotiating with Kim Jong Un in the future, and improving ties with China.[69] All these statements send conflicting signals. Besides, Lee’s views cannot be equated with the party’s stance on the trilateral. The latter encapsulates a spectrum of political views that influence the leader’s opinions, as was seen during Moon Jae-in’s tenure. For instance, the DPK does not favour compromising Seoul’s position on legacy issues in exchange for better ties with Japan. Another example of differing foreign policy perspectives was evident during the impeachment process when the opposition tabled a bill in the national assembly. The opposition said that “(t)he administration under Yoon has ignored the geopolitical balance, antagonized North Korea, China and Russia, insisted on bizarre Japan-centered foreign policies, and appointed figures lenient toward Tokyo to key government positions”[70] and called on the PPP to “reflect on the failed foreign and security policies and shift its policy stance to pragmatic diplomacy centered on national interests.” To assume that the president can ignore his party’s position on foreign policy would be naive. Therefore, it can be said that if the DPK comes into power, the TSC will bear the implications of worsening ties with Japan.
On the Japanese side, the frequent leadership changes have only had minimal impact on the country’s foreign policy. Therefore, even if there is any change, Japan’s policy towards North Korea—which was established under Shinzo Abe and recognises the importance of cooperation with the US and South Korea—will resume. For now, Ishiba is expected to continue the approach until he is in office, as he has done following his October election, taking forward Abe's legacy.[71]
The trilateral’s success will depend on three factors: The foreign policy vision of South Korea’s ruling dispensation; the US political leadership; and the degree of shared security assessment among the trilateral countries. Of these three, South Korean foreign policy towards North Korea has been the chief driver of the trilateral’s success. Therefore, the dissonance within the trilateral stems from the South Korean administration’s changing views of the latter as either an adversary or an estranged brother. On one side are South Korean progressives who prefer to have an independent North Korea policy, which creates a divergence with its allies on the North Korea situation, further limiting trilateral cooperation. Kim Dae-jung’s Sunshine Policy, Roh Moo-hyun's Peace and Prosperity Policy, and Moon Jae-in’s return to the Sunshine Policy led to a more engaging approach towards North Korea, which in effect resulted in less political investment with the US and Japan within the framework of the TSC.
At the same time, the Trump factor adds to the uncertainty of the trilateral’s future. Based on earlier track records and the composition of the Trump Cabinet, at least at the time of writing, a change in foreign and trade policy is expected,[72] wherein the focus will be more on resolving bilateral issues rather than deepening security and economic cooperation.[73] The second Trump Administration’s ‘America First’ approach differs from his first tenure and his predecessor’s, particularly on the issue of dealing with regional challenges such as North Korea and China.
Trump 2.0 is more conservative not only when it comes to trade and immigration, but also on security. While his first term saw disagreements between Seoul and Washington D.C., regarding trade and security arrangements, they could still be managed. The second Trump Administration is more inward-looking, prioritising US interests and neglecting allies’ concerns. Additionally, how the US has handled its ties with European allies on the Ukraine issue has compelled its Northeast Asian allies to rethink many security assumptions they once took for granted. This Transatlantic alliance faceoff has triggered security anxiety among US allies, leading to many questioning the country’s credibility and reliability in defending them.
Following these political changes, many within the strategic community in Seoul are rethinking their security arrangements with the US. Prominent strategic voices in South Korea have called for strengthening the country's independent deterrence posture, some advocating for its nuclearisation and diversifying diplomatic and security engagements. This changing conversation in South Korea points to a change in alliance perception at the macro level, the effects of which will trickle down to the micro level with time. Statements made by the US political leadership, including the President and Cabinet Ministers, have added to the displeasure towards the country, particularly among the conservatives, who are the strongest proponents of an alliance with the US. Trump’s sweet talk about Kim Jong Un and his recognition of North Korea as a nuclear state have raised doubts over the US’s commitment to the denuclearisation of the Korean peninsula. Additionally, designating South Korea as a sensitive country has shocked many among the ruling conservative party members.[c],[74]
The US-South Korea-Japan Trilateral Security Cooperation has evolved into an institutionalised framework focusing on critical issues ranging from defence cooperation, economic security, export controls, and developmental assistance to cyber cooperation. The challenges facing the trilateral threaten progress. Some factors driving these shifts have emerged from within the group due to bilateral disagreements and external developments that have provided alternatives to engage on the central concern of the TSC: the North Korean issue. Nonetheless, the trilateral will face bigger roadblocks as regional security threats become more complex and quasi-alliances, preferred by the Trump administration, take shape.
To ensure that the TSC will continue progressing through deepened cooperation, three things are important: efficient management of the ripple effects of the political developments within the group; nurturing bipartisan support within the public, political, and policy elites; and creating an agenda that incentivises the member countries to pursue pragmatic diplomacy centred on national interests. While acknowledging the growing regional threats and acting on them is crucial for the TSC, recognising the limitations of allies and respecting their security interests is equally so. Developing a common political conscience and not merely managing an ally's geopolitical expectations will strengthen the TSC’s role and relevance in the long run.
[a] The Six-Party Talks mechanism was established to address the North Korea nuclear weapons programme. The negotiations included countries like the US, China, Russia, South Korea, Japan, and North Korea.
[b] The Nixon Doctrine was announced on July 25, 1969, while focused on ushering a new era of foreign policy aimed at de-escalating the Cold War tension with China and the Soviet Union. The Doctrine emphasised US retrenchment from taking part in a far-away conflict.
[c] ‘Sensitive country’ designation by the US Department of Energy’s Office of Intelligence and Counterintelligence (OCI) is based on concerns regarding security risks with respect to non-proliferation, terrorism sponsorship, economic security threats, and regional instability. In South Korea’s case, the non-proliferation seems to be the factor, based on various reports.
[1] U.S Department of State, Secretary Anthony J. Blinken, Secretary of Defense Lloyd J. Austin, Republic of Korea Minister of Foreign Affairs Cho Tae-yul, and Republic of Korea Minister of Defense Kim Yong-hyun at a Joint Press Availability, October 31, 2024, https://2021-2025.state.gov/secretary-antony-j-blinken-secretary-of-defense-lloyd-j-austin-iii-republic-of-korea-minister-of-foreign-affairs-cho-tae-yul-and-republic-of-korea-minister-of-defense-kim-yong-hyun-at-a-joint-pre/
[2] Kim Eun-jung, “Yoon says S. Korea-U.S.-Japan cooperation to continue despite leadership changes,” Yonhap News Agency, August 29, 2024, https://en.yna.co.kr/view/AEN20240829004651315
[3] The White House, Background Briefing by Senior Administration Official, November 17, 1994, https://clintonwhitehouse6.archives.gov/1994/11/1994-11-14-backgrounder-on-trilateral-talks-with-japan-ands-korea.html
[4] The White House, Background Briefing by Senior Administration Official
[5] Eric Yong-Joong Lee, “The Six-Party Talks and the North Korean Nuclear Dispute Resolution Under the IAEA Safeguards Regime,” University of Hawai’i at Manoa, 2004, https://manoa.hawaii.edu/aplpj/wp-content/uploads/sites/120/2011/11/APLPJ_05.1_lee.pdf
[6] The White House, Promoting Peace and Stability on the Korean Peninsula, June 9, 1998, https://clintonwhitehouse5.archives.gov/WH/EOP/NSC/html/nsc-04.html
[7] The White House, Roundtable Interview of the President by Foreign Print Media, July 30, 2008, https://georgewbush-whitehouse.archives.gov/news/releases/2008/07/20080731-7.html
[8] U.S. Department of State, President Bush Meets with South Korean President Roh, September 7, 2007, https://2001-2009.state.gov/p/eap/rls/rm/2007/91842.htm
[9] Arms Control Association, The Six-Party Talks at a Glance, February 2023, https://www.armscontrol.org/factsheets/six-party-talks-glance
[10] Jayshree Najoria and Beina Xu, “The Six Party Talks on North Korea’s Nuclear Program,” Council on Foreign Relations, September 20, 2013, https://www.cfr.org/backgrounder/six-party-talks-north-koreas-nuclear-program
[11] The White House, “Fact Sheet: Advancing the Rebalance to Asia and the Pacific,” November 16, 2015, https://obamawhitehouse.archives.gov/the-press-office/2015/11/16/fact-sheet-advancing-rebalance-asia-and-pacific
[12] U.S. Department of State, “Trilateral Statement: Japan, Republic of Korea, and the United States,” September 6, 2001, https://2009-2017.state.gov/r/pa/prs/ps/2010/12/152431.htm
[13] “Detecting Nuclear Tests,” Comprehensive Nuclear-Test-Ban Treaty Organization, Detecting Nuclear TestsCTBTOhttps://www.ctbto.org › our-work › detecting-nuclear-tests
[14] “The Sinking of the Cheonan,” Center for Strategic and International Studies, April 22, 2010, The Sinking of the CheonanCSIS | Center for Strategic and International Studieshttps://www.csis.org › analysis › sinking-cheonan
[15] Kim Kee-seok, “Lee Myung Bak’s stunt over disputed islands,” East Asia Forum, August 19, 2022, https://eastasiaforum.org/2012/08/19/lee-myung-baks-stunt-over-disputed-islands/
[16] US. Department of Defense, Joint Statement of the 15th Republic of Korea-United States-Japan Defense Trilateral Talks, September 9, 2024, https://www.defense.gov/News/Releases/Release/Article/3900255/joint-statement-of-the-15th-republic-of-korea-united-states-japan-defense-trila/
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Abhishek Sharma is a Junior Fellow with ORF’s Strategic Studies Programme. His research focuses on the Indo-Pacific regional security and geopolitical developments with a special ...
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