[New Year Special Commentary Series] ⑤ Indo-Pacific Prospects for 2026 and Korea's Challenges

I. Introduction

The Indo-Pacific space, which has rapidly emerged in recent years, is a strategic space largely shaped by the United States. The international order in the Indo-Pacific in 2025 can be characterized by the chaos and uncertainty brought about by the inauguration of the second Trump administration. Questions are being raised about the durability and sustainability of the U.S. Indo-Pacific strategy due to the second Trump administration's disregard for alliances and its bilateral trade negotiation practices that undermine the multilateral trade order. Some argue that the Trump administration, focused on "America First" and selective engagement, will not pay much attention to network security represented by solidarity, connectivity, and collective security. The willingness to secure the trust and support of regional countries by providing public goods is also limited; the suspension of funding by the U.S. Agency for International Development (USAID) in early January 2025 and its abolition in July support this assessment. Furthermore, there are observations that the administration is passive regarding strategic designs to link security in Asia and Europe. At one point, the increasing frequency of the term "Asia-Pacific" instead of "Indo-Pacific" among U.S. policymakers led to arguments that the U.S. strategic commitment to the Indo-Pacific was weakening. However, at the ASEAN Expanded Defense Ministers Meeting (ADMM-Plus) in October 2025, U.S. Secretary of Defense Hagges explicitly used the term "Indo-Pacific," making it clear that the U.S. still perceives the Indo-Pacific as a core strategic space. Although a specific Indo-Pacific strategy document for the second Trump administration has not yet been released, this is a result of adjusted priorities within overarching strategic documents, not an indication that the strategic commitment to the Indo-Pacific itself has vanished.

Indeed, the U.S. Indo-Pacific strategy dates back to the first Trump administration. The first Trump administration, within a year of its launch in 2007, effectively revived the "Quad" (U.S.-Japan-Australia-India security cooperation) in 2017, which had been effectively suspended, declaring the full arrival of the Indo-Pacific era. Subsequently, the Biden administration comprehensively pursued its Indo-Pacific strategy, building a "lattice-type" security network that connects allies and security partners in layers. The Quad Foreign Ministers' Meeting, held on January 21, 2025, shortly after the inauguration of the second Trump administration, reaffirmed support for a "Free and Open Indo-Pacific (FOIP)" and agreed to strengthen maritime, economic, and technological cooperation among like-minded countries. The Quad Foreign Ministers' Meeting held on July 1, six months later, also reaffirmed this direction. Furthermore, the U.S.-Japan summit held on February 10, 2025, emphasized the importance of multi-layered mini-lateral cooperation mechanisms such as the Quad, as well as U.S.-Japan-South Korea, U.S.-Japan-Australia, and U.S.-Japan-Philippines. Although the Quad summit scheduled to be held in India at the end of 2025 was canceled due to deteriorating U.S.-India relations stemming from India's import of Russian crude oil and the U.S.'s imposition of reciprocal tariffs in response, the Quad continues to operate, focusing on non-traditional security areas such as advanced technology, cyber, critical minerals, maritime security, and logistics. Meanwhile, in the traditional security domain, the so-called "S-Quad" (U.S.-Japan-Australia-Philippines security cooperation), aimed at deterring China along the first island chain in the Western Pacific, is gradually taking institutional form.

The "Interim National Security Strategic Guidance," the draft "National Defense Strategy," and the "National Security Strategy (NSS)" released by the U.S. in 2025 all identify the Indo-Pacific as a core strategic region for the U.S. and set deterrence against China as one of the top priorities of U.S. foreign and security policy (Ha Young-sun 2026). For the U.S. to respond to the immediate threat from China without being "robbed" of excessive burdens by its allies, as President Trump put it, maintaining and strengthening a security network that can manage regional security in the Indo-Pacific at a low cost and high efficiency is not a choice that contradicts the Trump administration's views on alliances or its "America First" policy. The U.S.-led security network is not only effective in clarifying the division of roles among member states and coordinating joint responses to specific issues but also advantageous in relatively efficiently disseminating and monitoring the implementation of rules and norms as an "operating system." In summary, the U.S. is likely to pursue "coalitional hegemony" in the Indo-Pacific region through the U.S.-led security network (Loke and Emmers 2025). Consequently, the key variables for the Indo-Pacific region towards 2026 will be how the second Trump administration will maintain and manage the U.S.-led security network, and how China and regional countries will respond to it.

II. Strategic Environment in the Indo-Pacific in 2026

1. Sustainability and Adjustment of the U.S.-Led Security Network

Debates are actively underway in international political science circles regarding whether the U.S. remains a hegemon, a member of the G2, or if the world order is transitioning to a G0 or G- state. However, even if the military gap between the U.S. and China is narrowing, few argue against the fact that the U.S. is still the world's sole 'hyper power.' While President Trump's claims of having halted numerous ongoing conflicts, including the Thailand-Cambodia war, are exaggerated self-praise, they can be interpreted as evidence of America's overwhelming hegemonic status. Although U.S. Secretary of Defense Hagges stated in his speech at the "Reagan National Defense Forum" on December 6, 2025, that the era of U.S. unipolarity is over, this statement strongly emphasizes the increased role of allies. The issue, however, is the 'change in the nature' of U.S. hegemony. If the U.S. was a 'benign hegemon' providing public goods to maintain the liberal international order after the end of the Cold War, under the second Trump administration, the U.S. exhibits the characteristics of a 'malign hegemon.'

The U.S. is undermining the foundations of the liberal multilateral trade order it helped build, imposing so-called 'reciprocal tariffs' on countries worldwide through bilateral negotiations. These policies carry substantial coercive power based on America's hegemonic status. For instance, Vietnam, which benefited from the U.S.'s pressure on China during the first Trump administration, was subjected to a 46% reciprocal tariff on April 2, 2025, on the grounds that it served as a conduit for Chinese product exports. Subsequently, after Vietnam took measures to reduce its trade surplus with the U.S. and prevent the circumvention of Chinese product exports, the U.S. reduced the tariff rate to 20% on July 2. In negotiations held on the sidelines of the ASEAN Summit in October, the U.S. expanded the scope of duty-free application to some ASEAN countries while maintaining reciprocal tariffs of 19% for Cambodia, Thailand, and Malaysia, and 20% for Vietnam. In India's case, a 50% tariff was imposed, citing India's import of Russian crude oil.

Along with trade pressure, the second Trump administration is intensifying demands for increased defense spending from its allies. Since the beginning of its term, it has pressured NATO allies, Japan, South Korea, and Australia to increase defense spending to 5% of their GDP, of which 3.5% is direct military expenditure and 1.5% is indirect security expenditure according to NATO standards. At the U.S.-Australia Defense Ministers' Meeting held on the sidelines of the Shangri-La Dialogue on May 30, 2025, U.S. Secretary of Defense Hagges urged Australian Minister of Defense Richard Marles to rapidly increase defense spending to 3.5% of GDP, to which Australian Prime Minister Albanese publicly retorted, "We will decide our defense policy." South Korea promised to increase core military spending to approximately 3.5% of GDP at the ROK-U.S. summit held on October 30, 2025. The second Trump administration's NSS, released in December 2025, declared that the era when the U.S. "supported the world like Atlas is over" and explicitly demanded increased defense burden-sharing from allies. However, President Trump criticizes traditional allies as "free riders" while making relatively favorable remarks about leaders of authoritarian states like Russia and North Korea. This behavior undermines the credibility of the diplomacy of democracy and values that the U.S. has long emphasized.

Furthermore, the second Trump administration is strengthening its state capitalist tendencies and overtly pursuing the interests of major U.S. corporations. The approval of Starlink, a U.S. advanced technology company, for business operations in Vietnam, which had been pending during the U.S.-Vietnam tariff negotiations in early 2025, symbolically illustrates this. Additionally, in July 2025, the U.S. released "America's AI Action Plan," clearly articulating its hegemonic ambition to establish global standards and ecosystems by exporting U.S. AI products and platforms to allies and security partners. While the Huawei incident in the past was an exclusion strategy focused on blocking the use of Chinese technology, the recent U.S. approach has evolved into a more proactive technological hegemony strategy demanding the use of its own companies' technologies and products.

Amidst these changes, it is true that questions are being raised about the sustainability of the security network that the U.S. has built in the Indo-Pacific region. During the Cold War, the U.S. operated a "hub and spoke" alliance system centered on alliances with South Korea, Japan, Australia, New Zealand, and Thailand. In the post-Cold War era, it built a multi-layered and complex security network by interconnecting alliances and including security partners such as India, Singapore, and Indonesia. However, the U.S.-led security network does not guarantee U.S. centrality. During the Cold War, the U.S.'s central position was naturally maintained due to the asymmetrical power relationship between the U.S. and its allies within the "hub and spoke" alliance system. However, in the process of transitioning to the Obama administration's "principled security network" and the Biden administration's "lattice security network," the number of participating countries in the network expanded, and the level of threat perception towards China and shared values became increasingly dispersed and heterogeneous. In addition, the U.S. is reducing the scope of economic and military public goods it has provided to maintain the existing order and fulfill its security commitments. The protectionist policies of the first Trump administration, the CHIPS Act and the Inflation Reduction Act (IRA) of the subsequent Biden administration, and the reciprocal tariff policies of the second Trump administration are representative examples of this trend. The second Trump administration is fundamentally undermining the foundations of the 'International Liberal Order'—such as the rule of law, free trade, and democracy—which formed the basis of the U.S.-led security network.

Nevertheless, the U.S.-led security network in the Indo-Pacific region has maintained a relatively high degree of durability since the inauguration of the second Trump administration. This is because the U.S. is not only relying on 'Degree Centrality' and 'Closeness Centrality' in maintaining its centrality in the network but also enhancing 'Betweenness Centrality' and 'Eigenvector Centrality' simultaneously (Park 2023). First, in terms of 'Degree Centrality,' the U.S. has actively incorporated not only existing allies but also countries with which it previously had adversarial relations or those with non-aligned tendencies into the network. The normalization of relations and aircraft carrier port calls with Vietnam, the signing of a comprehensive security partnership with Indonesia, and the defense agreement with Papua New Guinea clearly demonstrate the U.S.'s strategic approach. By expanding the scope of the security network, the U.S. is simultaneously strengthening its accessibility across the South China Sea and the South Pacific and its capacity to deter China. Second, in terms of 'Closeness Centrality,' it is shortening the 'distance' between sub-regions and agendas by overlapping functional cooperation bodies. Functional cooperation within the Quad (Plus), such as maritime domain awareness, subsea cables, pandemic response, and logistics integration, enhances the network's density while strengthening the U.S.'s agenda-setting capability. In addition, the discussion initiated in Japan and the Philippines in 2025 to link the East China Sea and the South China Sea into a single 'theater' is also linked to the trend of strengthening the cohesion of functional cooperation beyond traditional security domains.

The U.S. is increasing 'Betweenness Centrality' and 'Eigenvector Centrality' to enhance the role of its allies and reduce its own burden. Third, in terms of 'Betweenness Centrality,' the U.S. is utilizing a 'sub-regional hub' strategy to effectively manage the vast and heterogeneous Indo-Pacific space. For example, the Quad, revived during the first Trump administration, plays a role in connecting Japan, Australia, and India as key hubs in Northeast Asia, the South Pacific, and the Indian Ocean, respectively. Fourth, in terms of 'Eigenvector Centrality,' the U.S. is amplifying its indirect influence by actively supporting and fostering sub-regional hub countries such as Japan, Australia, and India. As part of this strategy, the U.S. is promoting Japan's expanded regional and extra-regional security role, the normalization of ROK-Japan relations, Australia's strengthened leadership in the South Pacific, and the linkage between NATO and the four Indo-Pacific countries (South Korea, Japan, Australia, New Zealand - IP4).

In terms of strengthening centrality, what is noteworthy for the U.S. in operating the Indo-Pacific security network in 2026 is the aforementioned 'S-Quad.' As relations between the U.S. and India have cooled throughout 2025 due to India's purchase of Russian oil, the U.S. is operating the Quad as 'Quad Plus' focused on non-traditional security, while more fully activating the 'S-Quad,' which excludes India but includes the Philippines. The S-Quad is a mini-lateral security cooperation body that has expanded cooperation into traditional security areas beyond non-traditional security to counter China in the South China Sea and the Taiwan Strait. Since 2024, various combinations of bilateral, trilateral, and quadrilateral military exercises and joint maritime patrols among the four countries have been continuously expanding. The trilateral summit of the U.S., Japan, and the Philippines held in April 2024 and the Japan-Philippines reciprocal access agreement signed in July of the same year institutionally support this trend. Although the U.S. issued an executive order in January 2025 freezing USAID funds, it set some exceptions, with funding for the modernization of the Philippine military being a prime example. Furthermore, military and security cooperation is rapidly expanding, centered on the Philippines, not only with Japan and Australia but also with major NATO countries such as the UK, Canada, and France. This suggests that the U.S. has secured a strategic hub country in Southeast Asia, in addition to Japan in Northeast Asia, Australia in the South Pacific, and India in the Indian Ocean. The U.S. did not withdraw the intermediate-range missiles temporarily deployed for joint exercises with the Philippines in 2024 and, in fact, deployed additional missiles in 2025. The expanded security role of the Philippines as a Southeast Asian hub and the 'S-Quad Plus' have the effect of simultaneously increasing the U.S.'s 'Betweenness Centrality' and 'Eigenvector Centrality.'

2. China's Sphere of Influence Expansion: Intensification of U.S.-China Institutional and Normative Competition

The international relations order in the Indo-Pacific is not determined solely by 'power.' According to Kai He and Huiyun Feng, international order is influenced not only by military power but also by institutions and norms (He and Feng 2023). In terms of institutions, there are broadly three pillars in the Indo-Pacific region: first, the traditional international order centered on the United Nations (UN); second, ASEAN-led institutions; and third, the Indo-Pacific security network led by the U.S. However, all three face structural constraints. The UN order's normative authority and effectiveness are weakening as the U.S. itself takes actions that undermine it. ASEAN-centered institutions are based on the core principles of 'ASEAN Centrality' and consensus building, which inherently limit decision-making speed and efficiency. The U.S.-led security network has a structure where alliances and mini-lateral security cooperation overlap in a lattice form, but it does not yet possess comprehensive institutional mechanisms. Amidst the flaws of existing institutions, China is gradually expanding its sphere of influence institutionally through 'China-style multilateralism' consultative bodies such as the Shanghai Cooperation Organisation (SCO), Russia-India-China (RIC) cooperation, the BRICS (Brazil, Russia, India, China, South Africa) forum, and the Conference on Interaction and Confidence Building Measures in Asia (CICA). In other words, it is employing a strategy to build alternative multilateral institutions by presenting the 'Global Governance Initiative (GGI)' to exploit the gaps created by the weakening of UN, ASEAN, and U.S.-led institutions (Lee Dong-ryul 2026).

In the case of BRICS, Thailand and Malaysia became BRICS partner countries at the end of 2024, and Indonesia joined as a full member in January 2025. The subsequent addition of Vietnam as a partner country in June 2025 and the attendance of the Presidents of Brazil and South Africa at the ASEAN Summit in October suggest a growing interest and potential engagement with BRICS among ASEAN countries. Furthermore, the first trilateral summit between ASEAN, the Gulf Cooperation Council (GCC), and China was held in May 2025. While Islamic countries within ASEAN, such as Malaysia and Indonesia, place importance on cooperation with Middle Eastern countries, China utilized this framework to seek a joint response to U.S. protectionism. Moreover, the possibility of the SCO, led by China and Russia, expanding to Southeast Asia in the long term is also being raised. Although there are currently no SCO member states in Southeast Asia, considering the potential benefits of strengthened economic ties, access to energy and markets, and expansion into Central Asia, this possibility cannot be entirely ruled out.

In contrast to the U.S.'s strengthening protectionist policies, China has expanded regional multilateral trade cooperation. At the ASEAN-led summit in October 2025, China and ASEAN agreed on an expanded revision of the "China-ASEAN FTA 3.0." The RCEP Summit was also held for the first time since the signing of the "Regional Comprehensive Economic Partnership (RCEP)" in 2020. This can be interpreted as an attempt by China to strengthen its institutional centrality in the regional economic order, as the U.S. withdraws from the multilateral trade order. China's Premier Li Qiang's remarks at the ASEAN-China meeting on the sidelines of the ASEAN Summit in October 2025, indirectly targeting the U.S. by criticizing protectionism and unilateralism, symbolically illustrate this. Thus, the protectionist policies of the second Trump administration paradoxically provide a strategic environment for China to promote various (mini-)lateral cooperation and pursue regional power expansion.

In terms of norms, i.e., values and identity, China's trend of expanding its sphere of influence is also evident. Under the second Trump administration, the U.S. can no longer be perceived as a 'benign hegemon' defending the liberal order; rather, it exhibits the characteristics of a 'malign hegemon.' Limitations are arising in maintaining the 'we' identity that the U.S. has shared with its allies and security partners. However, the U.S. attempts to partially compensate for the loss of 'we' identity by highlighting the threat of 'thou,' emphasizing the authoritarian rule, human rights issues, and norm-violating behavior of China (Park 2025). On the other hand, as mentioned by Foreign Minister Wang Yi in his speech at a symposium hosted by the China Institute of International Studies under the Ministry of Foreign Affairs on December 17, 2024, China is emphasizing its legitimacy in the multilateral arena by promoting 'development' as the core banner of multilateral cooperation, strengthening cooperation with the 'Global South,' and pursuing the goal of emerging as the center of the world stage by seizing the opportunity presented by the U.S.'s pursuit of 'America First' policies.

One of the structural weaknesses of the U.S. Indo-Pacific strategy is the lack of a systematic geoeconomic response to China's 'Belt and Road Initiative.' The U.S. has responded to the Belt and Road Initiative through individual infrastructure investments and bilateral/trilateral/Quad cooperation with Japan, Australia, and India, but with limited success compared to China's overwhelming capital scale. China's intention to spread its sphere of influence through institutions and norms became even clearer in early 2025 when the U.S. issued an executive order freezing USAID funds. As numerous development cooperation projects in the Indo-Pacific region, supported by the U.S., faced the risk of suspension, China strategically utilized this opportunity to weaken U.S. influence in regional multilateral spheres and expand its own space. Indeed, President Xi Jinping's visits to Vietnam, Malaysia, and Cambodia in succession in April 2025 actively leveraged the diplomatic landscape of a "reduction in U.S. influence." In his 2026 New Year's address, President Xi Jinping stated, "Joining hands with all countries to promote world peace and development and build a community of shared future for mankind."

Amidst China's continued charm offensive, attention was focused on whether President Trump would attend the ASEAN-led summit held in October 2025. Given that President Trump had consistently skipped ASEAN-related summits except for the first year of his first term, the prevailing view was that he would follow a similar pattern in his second term. However, for President Trump, who claims to have halted eight wars worldwide, the ceasefire agreement ceremony between Cambodia and Thailand was a suitable stage to showcase his diplomatic achievements. President Trump, who visited Malaysia in late October 2025 to attend the ceasefire agreement ceremony, participated in the U.S.-ASEAN Summit (ASEAN+1) but did not attend the East Asia Summit (EAS), where major regional countries discuss the overall regional order. President Trump's selective participation demonstrates that the U.S.'s engagement with ASEAN remains a utilitarian approach focused on short-term gains and transactions, rather than a multilateral approach that shapes both norms and institutions. China is differentiating itself as a 'guardian of multilateralism' while expanding its institutional and normative influence.

3. U.S.-China Competition and Southeast Asia, the South Pacific, and the Indian Ocean: Expansion of Regional Middle Power Networks

As the geopolitical and geoeconomic competition between the U.S. and China intensifies in the Indo-Pacific region, Southeast Asia is one of the areas where the competition for influence between the U.S. and China is most fiercely contested. Although ASEAN officially professes neutrality between the U.S. and China, the tilt of member states towards either the U.S. or China is becoming increasingly apparent. As observed earlier, the Philippines is strengthening security cooperation with the U.S. through the "S-Quad," while Cambodia, which opened the Ream Naval Base in April 2025, shows a friendly stance towards China. The U.S. is strengthening maritime security cooperation to attract major Southeast Asian countries like Indonesia into its U.S.-led security network, and Japan is also aligning with the U.S. in providing Intelligence, Surveillance, and Reconnaissance (ISR) equipment through "Official Development Assistance for Security Capacity Building (OSA)." At the "ASEAN Expanded Defense Ministers Meeting (ADMM-Plus)" held in November 2025, the U.S. proposed the establishment of a joint maritime surveillance system based on unmanned aerial vehicles.

On the geoeconomic front, China is attracting regional countries to its side through large-scale infrastructure investments and development aid under the Belt and Road Initiative. In response to China, the U.S. signed critical minerals and rare earth agreements with four Southeast Asian countries—Malaysia, Thailand, Cambodia, and Vietnam—in October 2025. Notably, the trade agreements with Malaysia and Cambodia included clauses stating that "the agreement can be terminated if a competing agreement is signed that threatens the core interests or security of the United States," which can be seen as an example of the U.S.'s asymmetric and conditional geoeconomic strategy aimed at China.

However, amidst the intensifying U.S.-China strategic competition, the structural constraints of internal division and heterogeneous interests are becoming increasingly apparent, hindering ASEAN's effective response as a unified collective actor. In 2025, while discussions within ASEAN regarding the approval of the Myanmar military junta remained deadlocked, armed conflict occurred between Thailand and Cambodia. On May 26, clashes occurred in the border dispute area between the two countries, resulting in the death of a Cambodian soldier, and military tensions escalated into full-scale war from July 24. Despite an agreement on a ceasefire on July 29, the conflict persisted, eventually leading to the signing of the "Kuala Lumpur Peace Agreement" in October through the mediation of the U.S. and the ASEAN Chair, Malaysia. Nevertheless, clashes recurred on November 12, and after a large-scale confrontation on December 7, a new ceasefire was only agreed upon on December 27. The issue of approving the Myanmar military junta and the Thailand-Cambodia border dispute are representative examples demonstrating the weakening internal cohesion of ASEAN, amplifying questions about the effectiveness of the "ASEAN Centrality" and "ASEAN Consensus" principles that ASEAN has emphasized. Consequently, many Southeast Asian countries tend to prefer mini-lateral cooperation among a small group of countries with aligned interests, rather than adhering to the "ASEAN Way" for issues where comprehensive agreement at the ASEAN level is difficult. This is an attempt to complement the "ASEAN Way" with flexible cooperation methods for matters requiring swift and practical responses, rather than negating ASEAN Centrality and Consensus.

Meanwhile, in the South Pacific, Australia saw the Labor Party win a landslide victory in the general election on May 3, 2025, extending its term. Traditionally, Labor governments have been relatively more proactive in improving relations with China than Liberal governments, leading to assessments that conditions were created for normalizing relations between Australia and China, which had deteriorated due to trade disputes. However, as China's assertiveness in the South China Sea and the South Pacific continues, threat perceptions of China in Australia have not subsided. In February 2025, Chinese naval live-fire exercises in the Tasman Sea forced civilian aircraft to reroute, and in October, a Chinese fighter jet fired flares near an Australian maritime patrol aircraft in the South China Sea. Although trade relations between Australia and China appear to have superficially normalized on the occasion of summits in 2024 and 2025, concerns remain in Australia that China could resume economic coercion if it secures alternative mineral supply sources. Accordingly, Australia set diversifying mineral supply chains as a key policy agenda in 2025 and signed the "Critical Minerals Initiative" under the Quad framework and the "Critical Minerals Supply Chain Framework" between the U.S. and Australia. In terms of security, Australia continues to serve as the southern axis of the U.S.-led security network through large-scale joint exercises like "Talisman Sabre," while actively participating in S-Quad cooperation centered on the Philippines and strengthening maritime security capabilities in Southeast Asia.

Throughout 2025, a key concern in Australia was whether the second Trump administration would inherit "AUKUS" (U.S.-UK-Australia security cooperation), launched during the Biden administration. As projections of a decrease in the U.S. Navy's submarine fleet emerged, raising possibilities of a retreat from AUKUS in the U.S., Australia and the UK expressed concern. However, at the U.S.-UK summit held on the sidelines of the G7 Summit in June and the U.S.-Australia summit in October, President Trump confirmed the continuation of AUKUS and the schedule for providing nuclear-powered submarines. Subsequently, the promotion of AUKUS was reaffirmed at the U.S.-Australia ministerial "2+2" meeting in December, largely resolving the uncertainty.

In the South Pacific, Australia has actively responded to China's expansion of influence to maintain its own security influence. As China expanded infrastructure investments and security cooperation through the Belt and Road Initiative, Australia signed security agreements with several Pacific island nations and supported the strengthening of their policing and military capabilities. In 2025, along with the U.S. and Japan, it completed a large-scale subsea cable connecting Kiribati, Nauru, and Micronesia, also engaging in cyber security responses. Although certain limitations were revealed in responding to China's expanding influence in Vanuatu and Nauru due to China's persistent offensive, Australia achieved the outcome of securing a third ally in the South Pacific after the U.S. and New Zealand by signing a defense treaty with Papua New Guinea in September 2025.

In the Indian Ocean, the restoration of trilateral security cooperation between India, Australia, and France is being pursued. The so-called "Canberra-Delhi-Paris" security cooperation was launched in 2020 under the initiative of France but rapidly weakened when Australia canceled its submarine contract with France following the signing of the AUKUS agreement. Subsequently, with the recovery of Australia-France relations following the change of government to the Australian Labor Party in 2022 and the settlement of the compensation dispute, the foundation for restarting trilateral cooperation was laid. In 2025, India and Australia participated in France's "La Pérouse" exercise in January, India participated for the first time in the "Talisman Sabre" exercise hosted by Australia and the U.S. in July, and Australia and India signed a security agreement in October, marking substantial progress in resuming cooperation. On October 23 of the same month, the foreign ministers of the three countries met in New York on the sidelines of the 77th UN General Assembly to discuss maritime security issues. This series of movements indicates the re-emergence of the strategic importance of the Indian Ocean, connecting French Reunion Island, Australia's Cocos Islands, and India's Andaman and Nicobar Islands, and furthermore suggests the possibility of linkage with the U.S. and the UK via Diego Garcia.

Australia and India are significantly increasing bilateral and mini-lateral cooperation with regional and extra-regional countries in the Indo-Pacific region. For example, Australia placed an order for 11 next-generation destroyers worth approximately 9 trillion Korean won with Japan in August 2025, and Australia and India signed a security agreement in October of the same year. On the mini-lateral level, the third Indo-Pacific Dialogue involving Australia, South Korea, and Japan was held in Tokyo, Japan, on October 15, 2025. This aligns with the trend of U.S. allies and security partners emphasizing strategic alliances centered on regional countries, as the U.S.-China hegemonic competition intensifies and the second Trump administration prioritizes "America First." Major European countries are also participating in this trend; for instance, the NATO-IP4 linkage is emerging as a cooperation platform connecting Europe and the Indo-Pacific, regardless of direct U.S. involvement. On the sidelines of the G20 Summit held in South Africa in November 2025, Australia, India, and Canada launched a trilateral partnership to strengthen cooperation in new technologies.

From the perspective of Australia and India, cooperation with key hub countries in the Indo-Pacific region, such as Japan, South Korea, the Philippines, Vietnam, and Indonesia, can be expected to complement and strengthen the U.S.-led security network while gradually expanding mini-lateral cooperation led by regional countries. Furthermore, if key nodes of the U.S.-led network, such as Australia, India, Japan, South Korea, and the Philippines, consolidate their positions within the network through solidarity and expand their autonomy, it will prevent the network from excessively functioning as a tool for U.S.-China confrontation.

III. Strategic Considerations for South Korea

The unfolding dynamics of U.S.-China competition directly influence the formation of order in the Indo-Pacific region concerning military power, institutions, and norms, and have significant implications for South Korea's overall foreign strategy. South Korea is faced with the need for complex strategic judgments among choices such as strengthening its position within the U.S.-led security network, exercising strategic prudence considering China, and expanding security cooperation with regional middle powers and Europe.

Given that the U.S. is still the world's sole 'hyper power' in military terms, the necessity for South Korea to play a certain role within the U.S.-led security network is clear. Due to its unique situation of facing the North Korean threat, South Korea has been assessed as having a relatively low level of engagement in security agendas outside the Korean Peninsula. However, with the U.S.'s deterrence policy against China becoming a core component of its Indo-Pacific strategy, it is inevitable that its ally, South Korea, will also be required to contribute to a certain extent on key Indo-Pacific security issues. This demand becomes even more evident in an environment where strategic competition between the U.S. and China intensifies along the first island chain in the Western Pacific. Amidst escalating confrontation between the two camps centered on Taiwan and the West Philippine Sea, the "S-Quad (+)" framework, where Japan, Australia, and some NATO countries join the maritime patrols and exercises conducted by the U.S. and the Philippines, is taking concrete shape. Conversely, China is continuously escalating its assertive gray zone strategy in the South China Sea. The Philippines, as the ASEAN chair in 2026, is expected to strengthen S-Quad cooperation while urging the prompt conclusion of the "Code of Conduct in the South China Sea" by leveraging its position as ASEAN chair, thereby increasing pressure on China. South Korea's challenge lies in determining the scope and extent of its participation in the maritime security cooperation led by the U.S. and Japan. Media reports in early 2025 indicating that the Philippines sounded out South Korea's potential participation in the S-Quad suggest that this issue is indeed entering policy discussions. When requests are made to participate in existing regional maritime security cooperation frameworks, such as patrols in the Strait of Malacca or the Sulu-Sulawesi Sea, South Korea needs to make comprehensive judgments about the strategic effects beyond mere participation. South Korea's maritime security engagement is entering a phase where the scope and method of participation, rather than participation itself, are the key issues.

South Korea's recent expansion of participation in Indo-Pacific military exercises is an example of its external demonstration of intent to contribute to regional security beyond the Korean Peninsula, aspiring to be a 'globally responsible state' and a 'G7+ country.' In particular, strengthening security cooperation with Australia aligns with this direction. Since 2021, South Korea has continuously participated in the 'Talisman Saber' exercise, hosted by Australia and the United States, and conducted live-fire drills of its K-9 self-propelled howitzers on Australian territory in 2023 and 2025. These exercises have enhanced mutual trust through defense industry cooperation while also improving the practical training conditions for the South Korean military. Given the increasing number and scale of bilateral and multilateral military exercises in which South Korea participates, Japan's 'Reciprocal Access Agreement (RAA)' with regional countries serves as an important reference case for South Korea. South Korea should also positively consider concluding RAAs with countries like Australia and the Philippines.

If the Quad pursues the expansion of the 'Maritime Domain Awareness (MDA)' regime in the Indo-Pacific region, South Korea's participation could become another test case. The launch of the 'Indo-Pacific Maritime Domain Awareness Partnership (IPMDA)' was agreed upon at the 3rd Quad Summit in 2022, with detailed implementation plans discussed at the September 2024 summit, and the relevant direction was reaffirmed at the July 2025 Foreign Ministers' Meeting. Based on its intelligence, surveillance, reconnaissance, and maritime security cooperation capabilities, South Korea must comprehensively consider the benefits of expanded information sharing and integration into cooperation networks through participation, against the costs of potential impacts on relations with China and additional burdens of responsibility. The criterion for judgment should go beyond the gains and losses of individual issues to ensure consistency with the strategic goal of strengthening South Korea's position within the US-led security network. 'Maritime Capacity Building' for regional countries also needs to be systematically expanded beyond individual contributions, with greater coordination and cooperation with Quad countries and major NATO members. Maritime capacity building is highly justifiable in its contribution to the non-traditional security needs of regional countries, and it can simultaneously serve as a means to enhance South Korea's presence in a region of intense US-China strategic competition.

In response to China's naval expansion, the importance of strategic cooperation regarding the 'Maintenance, Repair, and Operation (MRO)' of US vessels is gradually increasing. South Korea, possessing advanced shipbuilding capabilities, needs to pursue strategic synergy through cooperative methods such as joint consortia, rather than focusing solely on competition with Japan, Australia, and India. The Philippines and the United States are pursuing facility expansions to utilize Subic Bay as an MRO base for the US Navy, and there were reports in July 2025 that the US planned to construct a vessel maintenance and repair facility near the South China Sea. The reactivation of HD Hyundai's Subic Bay shipyard starting in Q4 2025 can be evaluated as a cooperative model combining US private capital, Korean technology, and Filipino labor. South Korea needs to approach cooperation in shipbuilding and MRO with regional countries not just from an economic benefit perspective, but from a strategic standpoint that strengthens the ROK-US alliance and enhances South Korea's position within the US-led security network. It is rational to minimize competition with Japan, Australia, and India and seek a cooperative structure based on division of roles. The signing of a Memorandum of Understanding for cooperation between HD Hyundai and India's Cochin Shipyard in July 2025, and the Australian government's approval of Hanwha Group's acquisition of a 19.9% stake in Austal Australia in December, support this possibility.

Meanwhile, South Korea ultimately needs to aim for the role of an 'order-shaper' that actively influences the formation of the regional order, rather than remaining a passive 'order-taker' of the Indo-Pacific order being shaped by the US and China. The identity of an 'order-shaper' is a core vision for South Korea to organically link and pursue its Korean Peninsula, regional, and global strategies. The previous Yoon Suk-yeol administration designated South Korea as a 'Global Pivotal State (GPS)' and presented nine priority tasks for this role. Although the specific regional strategy of the current Lee Jae-myung administration has not yet been publicly announced, South Korea must further clarify its role as an 'order-shaper' in the future. Concurrently, it should continuously identify and pursue cooperative agendas necessary to fulfill such a role, prioritizing maritime security-related agendas to ensure both visibility and strategic effectiveness in the region.

For regional countries to play a meaningful role in maintaining regional order, possessing national strength beyond that of a middle power is insufficient; they must also secure a leadership position in their sub-region and serve as key connectors within networks linking these sub-regions. In the Indo-Pacific region, countries that can meet these conditions can be narrowed down to South Korea and Japan (Northeast Asia), Indonesia, Vietnam, and the Philippines (Southeast Asia), Australia (South Pacific), and India (Indian Ocean). While a single middle power has clear limitations in leading the establishment and maintenance of regional security order, these countries can secure a certain level of strategic leverage against the US and China by forming mini-lateral alliances.

South Korea needs to systematically strengthen bilateral and mini-lateral cooperation with key middle powers in the Indo-Pacific. With the restoration of ROK-Japan security cooperation in 2023, South Korea and Japan, along with Australia, are now in a position to seek mini-lateral cooperation not only in Northeast Asia but also in Southeast Asia and the South Pacific. Cooperative combinations such as ROK-Japan-Australia-ASEAN or ROK-Japan-Australia-Pacific Island Countries are also realistic options. South Korea and Australia's experience in joint development cooperation in Southeast Asia provides a foundation for expanding cooperation into the South Pacific. Based on the regular ROK-Australia ASEAN Policy Dialogue, institutionalizing regional linkage diplomacy could be considered by proposing a 'ROK-Australia South Pacific Solidarity Initiative' analogous to the 'ROK-ASEAN Solidarity Initiative.' The reduction of Official Development Assistance (ODA) budgets by a potential second Trump administration presents an opportunity for South Korea to expand its soft power through strategic and attractive ODA diplomacy. Given the heightened expectations following the previous administration's announcement of ODA expansion in Southeast Asia and the South Pacific, the current administration risks losing this opportunity if it chooses to maintain the status quo or reduce ODA.

Finally, South Korea should play the role of a 'bridge country' by promoting indigenous mini-lateral security cooperation led by regional countries or actively participating in existing cooperation mechanisms, while also creating conditions for China's participation. Furthermore, a strategic approach is needed to selectively participate in cooperation under China's 'China-style multilateralism,' within the scope that aligns with enhancing its position within the US-led security network. ■

References

Lee, Dong-ryul. 2026. “China's Diplomacy in 2026: Expectations for a Multipolar World Order and Active Pursuit of Expanded Global Roles.” *New Year's Special Commentary Series*. https://eai.or.kr/press/press_01_view.php?no=13470(Accessed: January 11, 2026).

Ha, Young-sun. 2026. “2026 ROK-US Relations Outlook: Adjustment of Core Interests and a Transition Period for Civilizational Leadership.” *2026 New Year Special Commentary*. East Asia Institute. https://eai.or.kr/(Accessed: January 11, 2026).

He, Kai & Feng, H. 2023. “International order transition and US-China strategic competition in the indo pacific.” Pacific Review, 36(2). 234-260.

Loke, B. & Emmers, R. 2025. “Coalition-building and the politics of hegemonic ordering in the Indo-Pacific.” Australian Journal of International Affairs, 79(4), 543–551.

Park, J. J. 2023. “The US-led security network in the Indo-Pacific in international order transition: a South Korean perspective.” Pacific Review, 36(2). 329–350.

Park, J. J. 2025. “American coalition building of the US-led security network in the Indo-Pacific: US influence-building measures.” Australian Journal of International Affairs, 79(4). 570–585. ■

■ Park, Jae-jeok_Professor, Graduate School of International Studies and Underwood International College, Yonsei University.

■ Responsible Editor: Lee, Sang-jun_EAI Research Fellow
Inquiries: 02 2277 1683 (ext. 211) | leesj@eai.or.kr