South Korea and Japan’s Responses to the US Latticework for the Indo-Pacific System

Since the turn of the century, the US government has increasingly pivoted toward Asia, responding to anticipated Chinese aggression, such as toward Taiwan or in the South China Sea, by seeking a new regional architecture to bolster alliances and partnerships, including the bilateral alliances that underpinned American strategy during the Cold War. This shift began under the Bush Jr. administration, while the Obama administration pursued it overtly with its “pivot” or “rebalance” to Asia.¹ Japan’s response to these American concerns and its sense of urgency to engage in regional institution-building became evident during the first Abe administration (2006-7),² intensifying after Abe returned as prime minister in 2012. In the case of South Korea, before Yoon Suk-yeol became president in 2022, participation in the broader Asian policy of US administrations was hesitant. Yoon changed that, impacting ties to Japan, trilateralism with the United States, and planning for an Indo-Pacific framework. This realignment was superimposed on the traditional hub-and-spokes, bilateral alliances. Yet, as Trump is primed to return to the presidency, Prime Minister Ishiba Shigeru has yet to be tested in foreign policy, and Yoon is suspended by impeachment, agreement is in doubt.

Under Joe Biden, the US strengthened its stance toward China and expanded its Indo-Pacific strategy. Military cooperation with allies advanced, and minilateral collaboration proliferated, evolving beyond traditional security cooperation to include sophisticated economic and other security initiatives. A complex web of interconnected partnerships became a reality, described as a “latticework” of relationships.³ Although the US vision for the Indo-Pacific was mostly accepted, debates proceeded on how effective the US strategy is. As the Pacific Command’s vision of a networked alliance structure nears its 24th anniversary, Japan and South Korea have reason to expect Donald Trump to sustain it, but new US leadership and new leadership uncertainty in both countries raise doubts about the degree of alliance agreement ahead.⁴

This article first reviews how the US vision for Asia aspires to establish an Indo-Pacific system, going beyond a patchwork of bilateral alliances by incorporating minilateral collaborations, elevating the role of Japan and the United Kingdom, and focusing on security in the Taiwan Strait and economic security. It represents a shift comparable in impact to an update of the Cold War’s San Francisco System. Secondly, the article examines how this vision is perceived within the region, noting the degree to which Japan and South Korea align with US expectations while highlighting the uncertainties regarding the sustainability of these efforts. With changes in the new US administration and the resulting challenges to US influence, it is anticipated that the US ability to shape regional order will continue to wane.

The Emerging US-led Architecture: the Indo-Pacific System

In Asia, US alliances have coexisted alongside ASEAN-based regional institutions since the Cold War. Recently, however, the US has placed substantial emphasis on minilateral cooperation within its alliances, expecting these relationships to play key roles in shaping both security and economic order. While the US focus on allies in Asia is longstanding, its current approach—relying on select groups of countries for rule-making and technological collaboration—represents a departure from tradition. The security architecture in this region was called by Kent Calder the “San Francisco System.” Its defining features include: numerous bilateral alliances structured around the United States; Japan’s unique role among the allies; and prioritized access to the US market.⁵ Unlike NATO, this architecture did not take on a multilateral form due to power asymmetries and a lack of a shared identity.⁶

After the Cold War, and especially in the 2000s, as discussions surrounding this architecture evolved significantly, “security architecture” became a popular term and new concepts, such as the Asia-Pacific Community, were put forth by leaders such as Australian Prime Minister Kevin Rudd. As the realities of China’s rise have become more evident, the US strategy in Asia has evolved beyond the “San Francisco System” into what can now be characterized as the “Indo-Pacific System,” consisting of at least five main features.⁷

First, while the US maintains its bilateral alliances, it has also promoted small-group cooperation among multiple allies and non-allied partners. The Quad (US, Japan, Australia, and India), initially emphasized in the latter years of the Trump administration, has been strengthened through regular summits under Biden. The Biden administration has also established AUKUS with the UK and Australia to facilitate submarine and advanced technology cooperation. In addition, the US-led Indo-Pacific Economic Framework (IPEF) encompasses 14 countries and includes supply chain, clean economy, and fair economy initiatives, beyond trade alone.⁸ In this growing network of minilateral partnerships, trilateral cooperation involving the US and Japan has gained significance. The Camp David trilateral summit with South Korea in the summer of 2023 addressed cooperation across traditional and economic security domains,⁹ and Japan-US-Australia, Japan-US-India, and other partnerships continue to expand in scope. Japan is expected to join AUKUS in advanced technology (pillar 2).¹⁰

Second, Japan’s role has become increasingly critical, as evidenced by its security policy transformation under the Kishida administration. While this shift is not purely a reaction to US pressure, Japan’s efforts to secure long-term US engagement align with the Biden administration’s policies. The UK’s post-Brexit involvement in the Indo-Pacific, which both the US and Japan have encouraged, further highlights this trend.

Third, stability in the Taiwan Strait has become a prominent focus, even surpassing issues such as North Korea and the South China Sea disputes. Taiwan’s geostrategic importance within the First Island Chain, its democratic values, and its advanced semiconductor production capabilities have all heightened its strategic significance.¹¹ As China asserts greater military dominance and increases activity near the Strait, the US has responded by intensifying military exchanges and arms provisions with Taiwan, and its allies are also expressing concern over Strait stability.

Fourth, economic security has become fully integrated into these partnerships. In April 2023, National Security Advisor Jake Sullivan introduced the “New Washington Consensus,” emphasizing the need to integrate security considerations into economic policy.¹² While the G7 summit in May 2023 emphasized “de-risking and diversification” over decoupling from China, the underlying security-centered approach to economic realignment remains consistent. This framework strongly influences both bilateral and minilateral cooperation.

Fifth, although the Biden administration initially employed strong rhetoric around regime competition through initiatives like the Democracy Summit, its recent prioritization of strategic partnerships with nations such as India and Vietnam demonstrates a pragmatic shift toward geopolitical imperatives over ideological alignment.¹³

The Indo-Pacific System embodies the US– especially Biden administration’s– approach and reflects the extent to which allies have aligned themselves with it. Japan, Australia, and South Korea emphasize minilateral cooperation and economic security while voicing concerns about Taiwan Strait stability. However, Japan’s continued commitment to ASEAN and its inclusive regional institutions—as the primary tools for strengthening regional relations—shows that the approaches of Asia-Pacific countries are not fully in sync with US policy. Many regional nations still view free trade as a key policy goal.

Japan’s Response to the Indo-Pacific System

Japan has played a pivotal role in shaping the Indo-Pacific’s security architecture, responding actively to US initiatives to adapt regional frameworks to the demands of the 21st century. Over the past two decades, Japan has developed strategic partnerships with key regional players, aligning its security policies with a vision for a “Free and Open Indo-Pacific” (FOIP). Japan’s evolving role in regional security, proactive diplomacy in promoting multilateral frameworks, and domestic policy reforms reinforce the Japan-US alliance while addressing emerging geopolitical challenges.

The “Indo-Pacific” concept, championed by Japan, reflects a broader regional vision encompassing the Indian Ocean and beyond. Japan’s pride in promoting this expanded framework is evident in its diplomatic efforts. During his second term, Prime Minister Abe Shinzo articulated the vision of FOIP in 2016, embedding it as a cornerstone of Japanese diplomacy.¹⁴  While FOIP’s substantive elements, such as infrastructure development and advocacy for free trade, may seem modest in advancing universal values, its most outstanding achievement lies in popularizing the Indo-Pacific framework globally.¹⁵ This concept, contrasting with the narrower “Asia-Pacific,” includes the Indian Ocean and, for Japan, extends as far as Africa’s eastern coast. US adoption of this framework, evident in policy shifts under the Trump and Biden administrations, has validated Japan’s strategic vision and strengthened its role as a regional leader. The US embraced the concept with vigor. By late 2017, Trump highlighted it in his APEC address.¹⁶ Subsequent actions included the rebranding of PACOM as INDOPACOM in 2018 and the publication of the State Department’s FOIP report in 2019.¹⁷ While some critics argue that the Indo-Pacific framework serves as a counterbalance to China, the Abe administration maintained active engagement with Beijing. Even ASEAN has released its own “ASEAN Outlook on the Indo-Pacific (AOIP),” reflecting the framework’s broad acceptance.¹⁸

Japan has actively supported US-led initiatives to build multilateral security frameworks, emphasizing trilateral and quadrilateral cooperation. Under the Biden administration, these efforts have gained momentum, with the US seeking to establish a lattice of security networks in the Indo-Pacific. Japan has played a leading role in mechanisms such as the Camp David trilateral summit in 2023, which led to institutionalized deeper cooperation between Japan, the US, and South Korea.¹⁹ Additionally, Japan’s partnership with Australia has advanced significantly, as seen in the 2024 trilateral defense ministerial meeting, where operational collaborations reached levels approaching a quasi-alliance.²⁰ Similar advancements have been made in Japan’s partnerships with the Philippines and the UK, the latter bolstered by post-Brexit security collaboration and support for the UK’s accession to the CPTPP.²¹ Japan’s security diplomacy underscores its commitment to enhancing US regional engagement and ensuring long-term stability.

Japan has undergone significant domestic reforms to enhance its defense capabilities, including a shift in legal frameworks surrounding its Peace Constitution. While these changes reflect Japan’s evolving security perceptions rather than direct US pressure, they align with longstanding American expectations. The Abe administration’s 2014 reinterpretation of collective self-defense marked a historic shift in Japan’s postwar security policy, building on decades of incremental changes such as increased Self-Defense Forces deployments in peacekeeping and coalition operations.²² Under the Kishida administration, the rapid increase in defense spending, the development of counterstrike capabilities, and the establishment of strategies for space and cyber domains signal a new phase in Japan’s security posture. These measures, partly influenced by the Abe’s enduring political legacy and Kishida’s political survival strategy, aim to secure US regional commitments.²³ Japan’s National Security Strategy underscores the imperative of deepening US-Japan cooperation across diplomacy, defense, and economic domains as foundational to regional stability.

Japan has also emerged as a global leader in economic security, aligning closely with US priorities. The 2021 Economic Security Promotion Act, encompassing critical infrastructure protection, resource security, advanced technology development, and classified patents, highlights Japan’s forward-thinking approach.²⁴ Establishing a security clearance system in 2024 further aligns Japan’s capabilities with its allies.²⁵ Economic security cooperation has become a central pillar of the Japan-US alliance, as evidenced by a long list of joint initiatives in supply chain resilience and advanced technology development outlined in the 2024 bilateral summit.²⁶ These efforts underscore Japan’s role as a model for economic security within the broader Western alliance.

Stability in the Taiwan Strait is a critical security concern for Japan. Japan has welcomed US efforts under the Trump and Biden administrations to bolster Taiwan’s defense capabilities. While official Japan-Taiwan relations remain limited to non-governmental cooperation, private-sector developments, such as TSMC’s joint venture in Kumamoto, highlight growing economic interdependence.²⁷ Japan continues to support regional stability through broader multilateral partnerships, emphasizing the importance of maintaining peace and security in the Taiwan Strait.

Japan’s understanding of the political values underpinning the international order is evident in its National Security Strategy and joint leaders’ statements with the US. Under Kishida, Japan emphasized the rule of law and a free, open international order, particularly in the wake of Russia’s invasion of Ukraine.²⁸ While Japan’s approach to universal values eschews the assertiveness sometimes seen in US internationalism, it resonates with recent American diplomacy, which has adopted a more restrained posture.

Japan’s proactive engagement in shaping the Indo-Pacific architecture has validated its foreign policy adjustments over the past two decades and reinforced US regional commitments. Japan has positioned itself as a key player in the evolving regional order by promoting the Indo-Pacific framework, advancing multilateral security partnerships, and implementing domestic reforms. While Japan remains sensitive to changes in US regional policy, its sustained efforts to guide and support American engagement reflect a shared commitment to stability and prosperity in the Indo-Pacific.

SouthKorea’s Response to the Indo-Pacific System

The response of South Korea to the evolving Indo-Pacific system can be effectively illustrated through the individual foreign policy strategies of the Moon Jae-in administration (2017-2022) and the Yoon Suk-yeol administration (2022-present). In 2017, the former announced the “Northeast Asia Plus Community for Responsibility Sharing,”²⁹ which included the “New Southern Policy” and the “New Northern Policy.” Subsequently, in 2022, the latter administration announced the “Strategy for a Free, Peaceful, and Prosperous Indo-Pacific Region.”³⁰  These two strategies demonstrate how South Korea responds to the evolving Indo-Pacific system by exploring its engagement and identifying pathways to strengthen its regional role within this framework.

Moon Jae-in Administration: Searching for Diplomatic Autonomy

The Moon Jae-in administration prioritized strategic autonomy in diplomacy amid the great power rivalry between the US and China. During the Trump administration, Moon initiated the New Southern Policy (NSP) to expand partnerships with ASEAN and India, while avoiding the use of the term “Indo-Pacific.”³¹ The NSP, along with the “New Northern Policy,” aimed to establish dual pillars of prosperity by engaging a broader range of regional partners.³² These initiatives reflected his vision of enhancing South Korea’s resilience and autonomy by bolstering its diplomatic influence in the region.

The formalization of the Indo-Pacific system during the Biden administration underscored the mismatches of aligning South Korea’s strategic approaches with the US expectations.³³ While the US sought to integrate its allies into a cohesive regional framework, Moon’s cautious approach to initiatives like the QUAD reflected a divergence between South Korea’s pursuit of strategic autonomy and the US expectations for allied cooperation.³⁴ This divergence was evident in Seoul’s hesitation to support or formally join such initiatives, despite US officials implying South Korea’s inclusion.³⁵ Similarly, the formation of AUKUS, which allowed Australia access to US nuclear submarine technology, sparked debate in South Korea regarding perceived double standards, particularly as Seoul’s own request for nuclear-powered submarines had been rejected by the Trump administration.³⁶

Also, Japan’s enhanced role within the Indo-Pacific system highlighted persistent challenges in the trilateral dynamic involving the US, South Korea, and Japan. By elevating the strategic importance of trilateral cooperation under its alliance-restoration framework, Washington sought to create a unified front to address regional security issues, particularly North Korea’s provocations and China’s growing influence. Within this context, South Korea and Japan engaged in several foreign ministerial and vice-ministerial meetings, focusing on security concerns.³⁷ However, the strained relationship between South Korea and Japan, which had already been prominent during the Moon administration, resurfaced and posed significant obstacles. Historical grievances, economic tensions, and different approaches to solve the North Korea issue, continued to hinder the development of a cohesive trilateral framework. Japan’s trade retaliation measures, including the removal of South Korea from its export “whitelist,”³⁸ exacerbated these issues and reinforced South Korean perceptions that Japan’s elevated role as a “second leader” in the Indo-Pacific system was misaligned with South Korea’s expectations. Even after leaving office, Moon Jae-in remained critical of the closer US-Japan-South Korea collaboration under Yoon Suk-yeol’s administration. Moon attributed this growing alignment to South Korea’s perceived economic decline relative to Japan, viewing Yoon’s trilateral initiatives as further entrenching these disparities.³⁹ This continued discord reflected the broader difficulty of forging effective trilateral cooperation within the Indo-Pacific system.

The Moon administration carefully navigated sensitive issues involving China, such as Taiwan and Hong Kong, driven by South Korea’s intertwined security and economic concerns. A potential military conflict in the Taiwan Strait posed significant risks for South Korea, as the US forces stationed on the peninsula could be drawn into the conflict, heightening the chances of North Korean provocations and exacerbating regional instability. This scenario also risked worsening the “Korea discount,” further undermining South Korea’s geopolitical standing.⁴⁰ However, as China’s military assertiveness in the Taiwan Strait grew more pronounced, the Taiwan issue gained prominence within the Indo-Pacific system. The Biden administration’s emphasis on value-driven and ideological alliances further highlighted the need for South Korea to play a more active role in regional security.⁴¹ Reflecting this shift, Moon, for the first time, included language in a US-ROK joint statement expressing concerns about peace and stability in the Taiwan Strait, aligning South Korea with the US and its allies on this critical issue within the Indo-Pacific order.⁴² Nonetheless, the Moon administration maintained a cautious approach by opting for measured language in such statements.⁴³ This approach reflected South Korea’s cautious diplomacy, aiming to align with its alliance obligations while avoiding actions that could escalate tensions with China.

In parallel with its efforts, the Moon administration’s economic policies reflected a strategic response to the securitization of economy within the Indo-Pacific system. Moon prioritized reducing South Korea’s economic dependency on great powers while fostering resilience through diversification of trade partners and stabilization of supply chains. Key initiatives included the K-Semiconductor Strategy, which provided tax incentives and loans to advance South Korea’s self-reliance in critical industries amid the global Chip War.⁴⁴ This policy also sought to position South Korea as a global leader in semiconductor manufacturing, reducing vulnerabilities tied to external supply chains. The Moon administration further expanded government support for addressing reliance on foreign materials, parts, and equipment technology, particularly in the battery industry, while tackling workforce shortages in advanced sectors.⁴⁵ These efforts aimed not only at mitigating economic vulnerabilities posed by the US-China rivalry but also at enhancing South Korea’s competitive edge in advanced technology industries critical to global value chains (GVCs). By fostering a “prosperity community” through regional cooperation and economic diversification, Moon sought to bolster autonomy and resilience in an increasingly polarized Indo-Pacific system.⁴⁶ The NSP complemented these efforts by emphasizing partnerships with ASEAN, particularly the Mekong regional countries, which have become key nodes in GVCs. These economic initiatives reflected Moon’s broader vision of positioning South Korea as a proactive and adaptive player capable of navigating the complex interplay of geopolitics and geoeconomics in the Indo-Pacific system.

Yoon Suk-yeol Administration: Indo-Pacific Strategy (2022-)
The Yoon administration redefined South Korea’s role in the Indo-Pacific region by aligning more closely with the United States and Japan. This is interpreted as a significant departure from South Korea’s traditional stance of strategic ambiguity, as Yoon adopted a policy of strategic clarity rooted in the US-ROK alliance.⁴⁷ Central to this approach is Yoon’s vision of a “global pivotal state,” which underscores South Korea’s evolving role within the Indo-Pacific system. ⁴⁸ Building on this foundation, South Korea has promoted its Indo-Pacific Strategy for Freedom, Peace, and Prosperity, broadening its engagement across the wider Indo-Pacific region. This strategy has reinforced South Korea’s commitment to regional stability while strengthening trilateral cooperation with the US and Japan, reflecting its broadened role perception as a pivotal actor in shaping the regional order.

Even before his election, Yoon expressed a strong interest in participating in US-led mini- and multilateral cooperation, such as the QUAD.⁴⁹ After taking office, the Yoon administration solidified this commitment by becoming a founding member of the Indo-Pacific Economic Framework (IPEF) alongside the US and Japan. Building on this, it also explored potential cooperation with AUKUS–where US National Security Council officials suggested that South Korea was being considered as a cooperative partner–following Japan’s example.⁵⁰ The culmination of these efforts was the Camp David summit, which marked a significant milestone in trilateral cooperation among the US, South Korea, and Japan. The summit introduced concrete measures to counter shared threats, particularly those posed by North Korea and China.⁵¹ To further institutionalize this collaboration, regular joint military exercises involving the US, South Korea, and Japan have been formalized. ⁵² Additionally, the establishment of the Japan-US-ROK Trilateral Secretariat has promoted the institutionalization and continued development of trilateral cooperation.⁵³ Moreover, through the Trilateral Indo-Pacific Dialogue,⁵⁴ the three countries have begun to actively discuss strategies to enhance cooperation across the Indo-Pacific region. Collectively, these developments reflect the South Korean government’s recognition of the strategic importance of the South Korea-US-Japan triangle in stabilizing the region and solidifying its role within the Indo-Pacific system.

This pattern is further reflected in the Yoon administration’s approach to geopolitically sensitive, China-related issues. Notably, Yoon adopted a more assertive stance on regional concerns such as the South China Sea and Taiwan. In an interview with Reuters, Yoon stated, “The Taiwan issue is not simply an issue between China and Taiwan, but, like the issue of North Korea, it is a global issue.”⁵⁵ He further emphasized South Korea’s firm opposition to any forceful change of the status quo. By framing regional security as integral to global stability, Yoon highlighted the interconnectedness of regional security, stressing that peace and stability in the Taiwan Strait are critical not only for Indo-Pacific prosperity but also for South Korea’s own security. This stance has been consistently reinforced in joint statements following summits with the US,⁵⁶ which shows the Yoon administration’s commitment to “value diplomacy” that aligns with the principles of the Indo-Pacific framework. Nevertheless, the Yoon administration’s pursuit of an enhanced role regarding the Taiwan issue remains a subject of ongoing debate. Critics argue that such an approach raises questions about whether it truly aligns with South Korea’s strategic interests.⁵⁷ However, the Yoon administration has actively sought to shape the evolving international security order by taking a strong stance on key security issues, through which it aimed to position Seoul as a proactive player in addressing shared security concerns within the Indo-Pacific system.

In the economic-security domain, the Yoon administration, much like its predecessor, pursued a comprehensive strategy to diversify South Korea’s economic partnerships while emphasizing flexibility and resilience amid escalating US-China tensions. A key initiative was the enactment of the K-Chip Act, designed to bolster the semiconductor industry by providing incentives for local investment and enhancing South Korea’s competitiveness in shifting global supply chains.⁵⁸ This focus on flexibility reflected concerns that US economic policies increasingly prioritized national interests over those of its allies. To address these risks, Yoon sought to revitalize trilateral economic cooperation with China and Japan, focusing on advancing the RCEP and strengthening supply chain cooperation to ensure economic stability.⁵⁹ At the same time, South Korea pursued independent initiatives with other partners, such as the South Korea-Australia Economic Security Dialogue, to expand its economic network beyond regional dynamics.⁶⁰ A significant achievement was the signing of the “Downing Street Agreement” with the United Kingdom, which elevated bilateral relations to a “global strategic partnership” and set a new benchmark for security and economic cooperation.⁶¹

In summary, while its security alliance with the United States remains a cornerstone of its diplomacy, South Korea has adopted differing approaches to address the issues created by intensifying US-China strategic competition and to redefine its role in the shifting international order. Despite these variations, both administrations have prioritized strengthening regional stability and fostering economic resilience, thereby solidifying South Korea’s position as a responsible and proactive actor within the Indo-Pacific system.

Concluding Thoughts: Rethinking US Leadership in the Indo-Pacific System

The US-led Indo-Pacific system faces ongoing challenges and burdens that highlight the complexities of maintaining the leadership of the US in both the security and economic domains. A key difficulty lies in the US struggle to establish an inclusive and cooperative regional framework that aligns with the diverse priorities of its partners. This has called into question the US ability to fully meet the expectations of its allies and partners. From the perspective of international relations theories, particularly constructivism and role theory, a leader’s role is constituted not only by its own aspirations but also through mutual social recognition by others.⁶² To stabilize its leadership, a nation should interact with partners and allies in a way that addresses their expectations. However, struggles to fulfill these expectations have contributed to an environment of uncertainty and complexity within the Indo-Pacific system.

A key challenge for the US lies in its ability to effectively establish a new security architecture that is both robust and widely acceptable within the Indo-Pacific region. Yet, achieving this remains complicated, particularly in ASEAN, which serves as the geopolitical and geo-economic center of the Indo-Pacific and serves as the foundation of regional multilateralism in East Asia.⁶³ While the US has prioritized alliances and minilateral groupings, such as the Quad and AUKUS, this approach has at times conflicted with ASEAN centrality and its principle of neutrality—key components of the region’s collective identity.⁶⁴ The challenge is exacerbated by the need to navigate existing institutions such as the East Asia Summit (EAS) and the ASEAN Regional Forum (ARF), which remain integral to the regional security architecture. These multilateral mechanisms highlight ASEAN’s enduring relevance and raise critical questions about how the US plans to integrate them into its broader Indo-Pacific strategy.⁶⁵ Successfully addressing regional concerns over China’s expanding influence while working within these established frameworks will be crucial for the US to establish a security order that is both robust and acceptable to regional stakeholders.

Amid these challenges, Japan’s role as a key partner for the US in maintaining the Indo-Pacific system highlights both opportunities and challenges in achieving a cohesive regional strategy. The growing expectation for Japan to take on a more central leadership role underscores its importance within the system, but it also reveals the complexities of navigating regional politics.⁶⁶ For example, Ishiba’s proposal for an “Asian NATO”⁶⁷ is likely to encounter considerable obstacles in unifying Indo-Pacific nations under a shared security framework, given the region’s varying threat perceptions and strategic priorities. Beyond this, Japan’s historical baggage complicates its credibility as a regional leader. Trust deficits stemming from unresolved historical grievances continue to shape its relations with neighboring countries, particularly South Korea, where bilateral tensions over historical and territorial disputes persist. This friction is compounded by diverging security priorities: while Japan remains mainly focused on countering China’s influence, South Korea places more emphasis on addressing the North Korean issues.⁶⁸

These challenges are not confined to Japan and South Korea but are mirrored across the Indo-Pacific. Many Southeast Asian nations, for instance, maintain parallel economic and security ties with China, making it difficult for them to fully align with US-led initiatives or adopt a more confrontational stance toward Beijing. ⁶⁹ This divergence further illustrates the complexity of constructing a unified regional order, where diverse national priorities and sensitivities must be reconciled to maintain inclusivity and stability within the evolving Indo-Pacific system.

In the economic-security domain, US leadership in the Indo-Pacific faces ongoing challenges as its protectionist policies continue to create friction with allies and partners. Both the Trump and Biden administrations have demonstrated an inward-looking approach to economic policy, prioritizing domestic industry over deeper international trade integration.⁷⁰ This tendency became particularly evident with the US withdrawal from the Trans-Pacific Partnership (TPP) and subsequent pursuit of policies such as the Inflation Reduction Act (IRA) and the CHIPS Act.⁷¹ While these policies aimed at promoting US interests in key sectors like semiconductors and electric vehicles, they have also triggered significant economic repercussions for allied economies, particularly in Asia.

While the US approach to economic security have strained its economic leadership in the Indo-Pacific, China has seized the opportunity to pursue a more inclusive strategy for regional economic integration. Initiatives such as the RCEP and China’s expressed interest in joining the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) highlight this divergence. These efforts stand in contrast to the US reluctance to engage in multilateral trade agreements that promote tariff reductions and facilitate market access.⁷² For example, the Biden administration’s IPEF lacks the traditional elements of free trade agreements, such as tariff reductions and market access provisions.⁷³ Instead, IPEF focuses on setting economic rules and standards, which limits its appeal and influence as a vehicle for comprehensive economic integration. This divergence may provide China with opportunities to expand its influence, as seen during the COVID-19 pandemic, when the “America First” approach created a leadership vacuum. Leveraging this moment, China sought to reposition itself as an “essential power” in the region, resetting international relations to its advantage.⁷⁴

Additionally, both the Trump and Biden administrations have positioned India as a core partner while seeking to revitalize the Quad.⁷⁵ However, this strategy reveals clear limitations since India keeps distancing itself from US-led security alliances.⁷⁶ Moreover, the US approach, which focused on a select group of countries, lacks a concrete strategy for integrating other critical actors, such as Southeast Asia, South Asia, and Oceania, including the Pacific Island nations. This imbalance underscores a broader challenge: the difficulty of establishing a comprehensive and inclusive regional framework that aligns with the diverse priorities of Indo-Pacific stakeholders.

These challenges could be further exacerbated by the return of a second Trump administration. A renewed emphasis on unilateral policies—such as increased tariffs, renegotiation of free trade agreements, and diminished security commitments—would likely weaken the regional structure the US has worked to build. Such an inward-focused approach risks alienating key partners and reducing US influence in shaping the Indo-Pacific system. Should the US fail to fulfill its leadership role effectively, regional countries may increasingly pursue self-oriented and assertive behavior to safeguard their strategic interests. This fragmentation would result in greater instability, further undermining the coherence of the Indo-Pacific system.

The challenges discussed in this article underscore the critical need for the US to recalibrate its leadership strategy within the Indo-Pacific system. While traditional alliances with countries like Japan, South Korea, and Australia remain important pillars of US engagement, a narrow focus on these partnerships has left significant gaps in addressing the broader needs of the region. At the same time, the adoption of economic security policies, which often prioritize domestic interests, has undermined efforts to establish an inclusive and cooperative regional framework. To address these challenges, the US needs to adopt a more inclusive strategy that extends beyond its traditional allies and addresses the diverse priorities of Indo-Pacific nations. This involves integrating regional institutions such as ASEAN in a more meaningful way, promoting shared prosperity, and fostering deeper multilateral engagement to address the existing gaps and build a more sustainable framework. Moreover, counterbalancing China’s growing influence and contributing to rebuilding a stable international order require the US to demonstrate consistent and reliable leadership, aligning its actions with the expectations of regional stakeholders. Without a renewed and consistent approach, the challenges of building a resilient and inclusive Indo-Pacific system are likely to persist, leaving the region in a state of uncertainty and instability.