Southeast Asia and Japan’s New Leadership

On October 1, 2024, Ishiba Shigeru was inaugurated as Japan’s 102th prime minister. He is an experienced politician in the Liberal Democratic Party (LDP) with in-depth knowledge of Japan’s defense, having served as direct general of the Defense Agency twice under the Koizumi Junichiro administration, as minister of defense under the Fukuda Yasuo administration, and as minister of agriculture, forestry and fisheries under the Aso Taro administration. However, having been unaffiliated with the mainstream factions in the LDP for nearly a decade, Ishiba was considered an unlikely candidate for prime minister. Indeed, his bids for the LDP presidency were defeated in 2012 and 2018 by Abe Shinzo and later by Suga Yoshihide and Kishida Fumio.

This leadership transition was unusual in three ways. First, the sudden announcement of Kishida’s resignation created an unprecedented level of intra-LDP political competition. Since the LDP president—a ruling party—would automatically become prime minister given the party’s majority in the Diet, the competition became intense, with nine candidates entering the race, including Takaichi Sanae, Hayashi Yoshimasa, Koizumi Shinjiro, Mogi Toshimitsu, and Kono Taro.¹ Second, the election process was highly uncertain because Kishida had previously dissolved factions due to slush fund scandals, making it difficult to openly organize voting blocs. Despite this, Kishida’s support rate hovered around 20 percent, leading an LDP presidential election without strong factional alignments.² Third, the next administration was expected to be short-lived, as a snap Lower-House election was anticipated. Amid this high domestic political uncertainty, Ishiba won the LDP presidency, thereby securing the premiership.³

With this domestic political turbulence, one of the key issues drawing significant attention is how foreign countries will react to the future of Japan’s foreign policy. Since the second Abe administration in 2012, Japan has pursued a proactive diplomacy, introducing initiatives such as the “Free and Open Indo-Pacific” (FOIP) vision. Successive administrations led by Suga and Kishida adopted FOIP as a core diplomatic agenda rather than abandoning the FOIP narrative. Ishiba followed suit, incorporating the concept into his first policy speech on October 4, 2024, stating that Japan would uphold its FOIP vision and the rules-based international order.⁴ However, given the evolutionary nature of the concept, it remains unclear what FOIP means to Ishiba and whether continuity or change will prevail in foreign policy under the Ishiba administration.

Among the key stakeholders in Japan’s FOIP are its foremost ally, the United States, and other like-minded partners. However, it is the Southeast Asian states that may cast decisive votes on the success of Japan’s FOIP. Although Southeast Asia is highly diverse in political systems, strategic orientations, and levels of economic development, the region is located at the heart of the Indo-Pacific region, spanning from East Africa to the American West and encompassing both the Pacific and Indian oceans. Southeast Asia holds vital sea-lines of communication between these oceans and from north to south through the South China Sea. In addition, the region’s Association of Southeast Asian Nations (ASEAN) has served as the core of East Asian multilateralism in East Asia and the Asia-Pacific since the end of the Cold War.  

In this context, by examining Southeast Asia’s general and initial reactions to Ishiba’s new leadership and the future of Japan’s foreign policy, I argue that Japan can maintain a positive relationship with ASEAN and its member states despite their negative responses to Ishiba’s proposal for an “Asian NATO.” However, in the long term, given the weakened domestic political foundation for the LDP to sustain a consistent foreign policy, along with the rapidly evolving international environment—including the intensification of US-China strategic competition, uncertainties surrounding US foreign policy under the Trump administration, and the emergence of new leadership in Southeast Asia—this positive relationship cannot be assured. In this sense, Japan needs to take the initiative to sustain this relationship not only by ensuring a robust follow-up with the implementation plan of the vision statement created at the 50th anniversary of ASEAN-Japan friendship cooperation in 2023 but also by reshaping a regional institutional architecture in the Indo-Pacific region under its FOIP concept.

This article is organized into four sections. The first section examines Ishiba’s foreign policy outlook in the context of Japan’s domestic political turbulence and Southeast Asia’s initial response. It also explores the resilient characteristics of Japan-Southeast Asian relations, derived from the 1977 Fukuda Doctrine, analyzing how Japan and Southeast Asia have maintained this relationship since. The second section reviews survey data from The State of Southeast Asia, produced by the ISEAS Yusof Ishak Institute from 2019 to 2024, to discern trends in general perceptions of Japan in Southeast Asia. The third section focuses on contemporary Japan-Southeast Asian relations—their diplomatic efforts to further strengthen their comprehensive relationship. The last section discusses the prospects of the Japan-Southeast Asia relationship under the Ishiba administration.   

Japan’s Foreign Policy under New Leadership: Ishiba Shigeru

Southeast Asia’s responses to Japan’s new prime minister have been relatively muted for three main reasons. First, Ishiba’s foreign policy stance toward Southeast Asia remains unclear. Although he has expertise in defense policy, his focus has primarily been on managing the US-Japan alliance, particularly the US forces stationed in Okinawa. Ishiba’s motivation to revise the Status of Force Agreement (SOFA) with the United States stems from his personal experience with the 2004 US military helicopter crash at the Okinawa International University, near the Marine Corps Air Station in Futenma.⁵ As director-general of the Defense Agency, Ishiba recognized the high risk of accidents at the Futenma base, which was surrounded by the city, but faced criticism for being unable to address this risk fully, as the existing SOFA did not permit Japanese authorities—including police, local government, and university staff—to access the crash site.⁶ This issue continues to dominate his defense agenda.

Admittedly, Ishiba’s another major foreign policy agenda, the establishment of an “Asian NATO,” has sparked controversy in Southeast Asia and beyond.⁷ His strategic thinking generally reflects a traditional balance-of-power approach, focusing on perceived threats from North Korea, China, and Russia. Ishiba has demonstrated, as seen in his discussion in the Diet sessions in the 2000s, an in-depth understanding of constitutional and political constraints on the use of the Japanese Self-Defense Force, the distribution of military capabilities in Northeast Asia, and the strategic utility of the US-Japan alliance.⁸ However, his idea of an “Asian NATO” remains underdeveloped. Ishiba strongly believes that Russia’s aggression toward Ukraine was due to Ukraine not being a NATO member, reinforcing his conviction that a concrete collective self-defense mechanism is necessary to deter China effectively. He envisions the institutionalization of the Quad as part of this mechanism. Yet, significant questions remain about how Japan can navigate its constitutional limits on the use of force and which state would join such a defense framework, which could be potentially divisive and lead to a “Cold War 2.0.”

Several media outlets and specialists from ASEAN member states quickly reacted to Ishiba’s Asian NATO proposal. Some in Singapore suggested that Southeast Asia is unlikely to support the idea, while the Jakarta Post in Indonesia strongly criticized it, expressing reluctance toward a more militarized Japan through the establishment of an Asian NATO.⁹ Ishiba’s primary focus on balance of power politics suggests he may not have fully considered such reactions. Further, it remains uncertain whether he understands the complex regional dynamics and the broader security architecture in East Asia—much of which is shaped by defense diplomacy within ASEAN-led institutions, such as the ASEAN Regional Forum and the ASEAN Defense Ministers’ Meeting (ADMM)-Plus. Given ASEAN emphasis on “inclusivity” and “cooperation” under its institutional principle of ASEAN centrality, which grants it chairpersonship and agenda setting power in East Asia’s multilateral framework, a new collective defense system could significantly undermine this ASEAN centrality.

Facing hesitancy and severe criticism from domestic and international audiences, including the United States and India, Ishiba omitted the “Asian NATO” concept from his inaugural policy speech and during his initial diplomatic visits to ASEAN member states in October 2024. However, he instructed Onodera Itsunori, a minister of defense under the Abe administration and the current chairperson of the LDP Policy Research Council, to establish a body within the LDP to discuss international security, including the potential formation of an Asian NATO.¹⁰ Consequently, the idea is still under consideration, with its formal proposal contingent on internal LDP deliberation. That said, if this initiative is advanced without careful handling and consultations with other states, particularly ASEAN members, it is highly likely to face rejection.  

Second, Japan is still grappling with significant political uncertainty. The coalition between the LDP and Komeito has lost its majority in the Lower House for the first time since 2012. Specifically, the LDP now holds 191 seats while Komeito holds 24, totaling 215 out of 465 seats.¹¹ Both parties suffered substantial losses, the LDP losing 56 and Komeito 8. Therefore, the immediate challenge for them was to secure majority support for Ishiba as prime minister during the extraordinary Diet session on November 11. Admittedly, Ishiba stayed as prime minister due to the opposition’s lack of unity to propose an alternative. Also, the conservative factions within the LDP, largely led by Aso Taro and Takaichi Sanae, have seen a decline in political influence, reducing their ability to challenge enough to take down Ishiba.

Two ongoing challenges remain: the LDP’s struggle to form a majority for policy decisions; and the Upper-House election scheduled for July 2025, when the LDP needs to demonstrate a commitment to reforming its administrative processes to prevent corruption and regain public trust. Consequently, Japan’s political environment is likely to be less stable than during previous LDP administrations, adding uncertainty to its foreign policy direction.

Third, Japan’s policy toward Southeast Asia has remained relatively consistent, fostering stable economic and political engagement since 1977, when Prime Minister Fukuda Takeo launched the “Fukuda Doctrine” in Manila.¹² In this speech, Japan promised to” (1) refrain from becoming a military power; (2) cultivate the relationship of “heart-to-heart” understanding; and (3) become “an equal partner” with Southeast Asian states. Prior to 1977, despite Japan’s growing economic engagement in the region, political and economic tensions between Japan and Southeast Asian states were common. For example, Japan’s synthetic rubber industry posed a threat to Southeast Asia’s natural rubber industry by outcompeting, and Japan’s economic activities were often seen as self-serving, which hindered trust-building with Southeast Asian states. Anti-Japanese sentiment was evident during Prime Minister Tanaka Kakuei’s visit to Indonesia and Thailand in 1974, demonstrated by intense protests that ultimately forced Tanaka to shorten his trip.¹³ In this context, the Fukuda Doctrine became a foundational step toward fostering a constructive relationship between Japan and Southeast Asia.

Indeed, Japan-Southeast Asia relations have been stabilized since then. While political and security issues were often put on the backburner, socio-economic cooperation, particularly through economic assistance, rapidly expanded. Japan has consistently provided Official Development Assistance (ODA) to Southeast Asia since 1969, totaling JPY18.4 trillion by 2019. In the post-Cold War era, Japan has diplomatically supported ASEAN’s initiatives to establish multilateral frameworks, such as the ASEAN Regional Forum (ARF), ASEAN+3, and the East Asia Summit (EAS). Since the 2010s, Japan has also implemented various capacity-building programs for ASEAN member states, helping to strengthen their law enforcement and defense capabilities under the “Vientiane Vision” and “Vientiane Vision II.”¹⁴ Furthermore, Japan has supported postwar reconstruction in the Indo-China states, such as Cambodia and Vietnam, since the 1990s through initiatives such as cooperation on the Cambodia-Laos-Vietnam Development Triangle and Japan-Mekong Cooperation.¹⁵ These efforts have been consistently sustained by Japanese bureaucracies, even during the period of frequent prime minister changes from 2006 to 2012.

Given these three factors, Southeast Asian states are adopting a “wait-and-see” posture toward Japan’s new leadership. Obviously, if any abrupt changes in Japanese foreign policy were to harm ASEAN’s regional interests, such as undermining ASEAN centrality and disrupting ASEAN unity, ASEAN member states would likely express their disapproval. However, in the absence of such shifts, Southeast Asia is expected to continue quietly monitoring Japan’s foreign policy direction.

Southeast Asia’s General Perception of Japan

The reason that Japan’s domestic political uncertainty did not draw any rapid reactions also stems from Southeast Asia’s long-standing perspectives on Japan. According to the surveys conducted by the ISEAS-Yusof Ishak Institute, three key perceptions have stabilized Japan’s position in Southeast Asia: Japan’s trustworthiness; its alternative strategic role; and its political and security posture.¹⁶

First, Japan has consistently since 2019 been regarded as the most trustworthy state among major regional actors, namely, China, the EU, India, and the United States. 50-70% of Southeast Asians have believed Japan would “do the right thing” for international peace and prosperity, while the United States fluctuated between 30-50% and China remained steady at 20-30%. Many Southeast Asian states still view Japan as an important economic power and a responsible stakeholder in supporting international law. Despite its relative economic decline since the 1990s, Japan remains the world’s fourth-largest economy, and its diplomatic stance and messaging toward Southeast Asia are considered well-managed in the region.

Obviously, there exist concerns in Southeast Asia that Japan might become distracted by domestic instability and Northeast Asia’s security environment, a view shared by around 30-40 percent of Southeast Asian since 2020. Therefore, Japan’s current domestic political turbulence could impact perceptions. However, this does not imply a shift in their immediate view of Japan’s fundamental diplomatic stance. These concerns center more on Japan’s potential and ability to achieve its regional and global objectives, rather than on its trustworthiness. Moreover, Southeast Asian perspectives on Japan are generally positive, with over 50% of respondents across the 10 ASEAN member states expressing favorable views, except for some occasional deviations, such as Laos in 2020, Cambodia in 2022 and 2023, and Myanmar in 2023. These attitudes contrast sharply with views toward the United States and China, where opinions are more varied: for instance, the Philippines and Vietnam are consistently wary of China, while Indonesia and Malaysia are often skeptical of the United States.  

Second, Japan remains the top choice as a third-party actor under the US-China strategic rivalry. To be sure, the EU has been ASEAN’s top preference since 2021—with around 40% of Southeast Asians consistently choosing the EU and approximately 30% selecting Japan. Given its economic and defense capabilities and its growing engagement in the Indo-Pacific region, including Southeast Asia, it is not surprising that the EU is viewed as a reliable partner for navigating the US-China rivalry. However, as an international institution based in Europe, the EU can face decision-making challenges and is geographically distant from Southeast Asia. In this regard, Japan also becomes an important partner because of its geographical proximity and active role in ASEAN-led institutions. In 2024, for instance, Brunei, Indonesia, and Singapore chose Japan over the EU. Moreover, compared to other regional states, such as Australia, India, South Korea, and the United Kingdom, Japan ranked significantly higher, with over 15% differences between Southeast Asian favoring Japan and others. This underscores Japan’s credibility and reliability.

Nevertheless, Southeast Asia’s strategic choice may be more economically oriented than defense driven. Given the US military presence through its bilateral security alliances and China’s growing military footprint in East Asia and beyond, no other states or institutions can match their influence militarily. On the other hand, the economic and development commitments made by the EU and Japan in Southeast Asia are relatively substantial. Thus, if economic and financial decoupling between the United States and China were to occur, Southeast Asia might look to the EU and Japan as viable alternatives. This is also because, although both are strong US allies and partners, their approaches differ from that of the United States. For instance, Japan has adopted a softer approach toward Myanmar and Cambodia, maintaining engagement despite their non-democratic status. These postures and engagements have influenced Southeast Asia’s perception toward Japan.

Third, Japan’s political and security posture is non-threatening to Southeast Asia, which views the United States and China as the two most influential powers, both politically/strategically and economically, with China leading in both areas. Since 2019, 40-55% of Southeast Asian have considered China the most influential political and strategic power, and 60-80% view it as the leading economic power. On the other hand, the United States ranked second, with approximately 30% seeing it as the most influential political and strategic power and around 10% as the top economic power. Beyond the United States and China, ASEAN holds the third position in both economic and strategic importance, as it represents the region’s primary organizational structure. Japan ranks fourth in both strategic an economic term, above Australia, the EU, India, South Korea, and the United Kingdom.

While Japan’s economic significance in Southeast Asia is understandable, its strategic importance may be less obvious. Yet, the nature of Japan’s political and security engagements sheds light on this. Firstly, Japan has supported Southeast Asia’s defense diplomacy and capacity-building efforts. By consistently participating in ARF and ADMM-Plus, Japan has provided maritime law-enforcement assets and defense equipment, such as patrol ships and radar systems, through its ODA and the Official Security Assistant (OSA) programs.¹⁷ These contribute to strengthening Southeast Asian defense capabilities without fostering excessive dependence on Japan, thus ensuring national and regional autonomy. Secondly, Japan holds a commitment to not becoming a military power in East Asia as promised in the 1977 Fukuda Doctrine. Each time Japan adjusts its defense policies, such as the 2014 re-interpretation of Japan’s constitution to allow for collective self-defense, it reassures Southeast Asian states that such shifts would not lead Japan to be a regional military power. Japan’s continuous constraints on power projection capabilities also offer reassurance that Japan would be strategically important without posing a military threat to the region. These Southeast Asian states’ perceptions have not been developed overnight. Japan has been building this relationship since the 1970s, helping to foster a resilient and positive perspective toward Japan in Southeast Asia.

Managing Relationships: FOIP and the 50th Anniversary of Japan-ASEAN Relations

To maintain stable relationships, Japan has also adjusted its strategic posture toward ASEAN and Southeast Asian states, particularly since the 2010s. During the Cold War, as Japan experienced rapid economic growth, becoming the world’s second largest economy, it provided economic assistance to regional states, creating an interconnected economic network in Asia—the so-called “flying geese” model of economic development. Even after the economic downturn following the bursting of the bubble economy in the early 1990s, Japan was able to support new ASEAN members, namely, Cambodia, Laos, Myanmar, and Vietnam, in their economic development through the 1990s and 2000s. However, it became increasingly apparent that Japan could not sustain the same level of economic influence over Southeast Asia, because of not only the rise of China but also the growth of Southeast Asian economies.

In fact, Japan’s economic relationship with Southeast Asia has shifted significantly. Although Japan remained ASEAN’s top trading partner in the post-Cold War period, accounting for over 25% of ASEAN’s total trade between 1990 and 2000, its share began to decline from 2001. In 2007, China surpassed Japan as the top trading partner and has held that position since.¹⁸ Japan’s economic assistance through ODA remained substantial, but its ODA budget peaked in 1997 at JPY 1,168 billion and then gradually declined to JPY 542.2 billion by 2015, the lowest point.¹⁹ In the meantime, China increased its economic assistance, particularly through the Belt and Road Initiative (BRI) launched in 2013. A notable example of Japan’s diminished economic influence was China’s successful bid over Japan for the high-speed rail project between Jakarta and Bandung in 2015.²⁰ In short, Southeast Asia no longer relies solely on Japan for its economic development, with China offering a strong alternative source of assistance. In response, Japan has aimed to position itself as a truly “equal partner” to Southeast Asian states and ASEAN.

Additionally, the evolution of Japan’s FOIP concept reflects Japan’s incorporation of Southeast Asian perspectives. In 2016, Abe launched the “Free and Open Indo-Pacific Strategy” to expand Japan’s strategic horizons in the Indo-Pacific.²¹ Initially, however, the strategy was conceptually quite vague, and did not define ASEAN’s role instead emphasizing Japan’s ties with the United States, Australia, and India. Given this lack of clarity and the initial focus on US allies and partners, ASEAN member states’ reactions were largely muted except for a few. Among them, Cambodia was the first ASEAN member to support Japan’s FOIP strategy, and the Mekong-Japan Summit in 2017 came to a consensus on cooperation.²² Yet, this is because the members of the Mekong-Japan cooperation did not consider it a strategic concept, but rather, they regarded Japan’s FOIP strategy as a development initiative. At the same time, some ASEAN members were skeptical, concerned that the FOIP might serve as a counterbalance China. This sentiment grew more apparent when the United States adopted the FOIP narrative in late 2017 and early 2018, aligning it with the US National Security Strategy and National Defense Strategy, which emphasized countering China.  

The Japanese government then sought to distinguish its FOIP from the US version by emphasizing ASEAN’s importance.²³ In early 2018, the Japanese Ministry of Foreign Affairs released the FOIP geographical map indicating ASEAN as the central region. By mid-2018, Japan had dropped the term “strategy” in favor of “vision” or simply FOIP, responding to concerns from some ASEAN members that the word “strategy” implies a countermeasure against a specific state.²⁴ Japan subsequently stressed ASEAN centrality and unity in the region. After ASEAN introduced the ASEAN Outlook on the Indo-Pacific (AOIP) in 2019, Japan took the initiative to align its FOIP with AOIP, issuing a joint statement focusing on cooperation with AOIP.²⁵ This move demonstrated Japan’s attempts to reassure ASEAN member states that its FOIP vision is not intended to contain China but to promote regional cooperation through a rules-based international order. Politically, as ASEAN plays a central role in regional multilateralism, gaining ASEAN’s support has become essential for Japan in advancing its agenda.

Japan’s strategic posture toward ASEAN became more pronounced in 2023, marking the 50th anniversary of ASEAN-Japan friendship and cooperation. Throughout the year, Japan and ASEAN member states held both Track-1 and Track-2 meetings to shape the direction of the future collaboration, culminating in the “Joint Vision Statement on ASEAN-Japan Friendship and Cooperation: Trusted Partners” along with an implementation plan. Since the 2003 Tokyo summit, Japan and ASEAN have held a commemorative summit every decade, issuing a similar vision statement with three primary themes: economics, political security, and socio-cultural. In both 2003 and 2013, these themes were listed in this order.²⁶

However, in 2023, the order of themes changed to socio-cultural, economic, and political security cooperation. This does not imply a difference in the importance of each theme but rather highlights the focus on human exchanges between Japan and ASEAN member states for future collaboration. As the power gap between Japan and ASEAN continues to narrow, it is imperative for both sides to adjust people’s perceptions—no longer viewing the relationship as solely donor and recipient—by promoting human exchanges across various societal level. To this end, Japan created the “Partnership to Co-create a Future with the Next Generation: WA Project 2.0,” aiming to facilitate the exchange of more than 10 million people by 2023.²⁷

This shift is also reflected in Japan’s economic policy toward ASEAN. Economic cooperation between Japan and ASEAN has broadened to include areas such as economic development, trade, finance, and environmental cooperation. Among these, connectivity has emerged as a key theme, with Japan prioritizing dialogue to understand the needs and demands of its partners, thus emphasizing a “co-creation” approach. In fact, ahead of the ASEAN-Japan joint vision issued in December 2023, Japan launched the “Co-creation for common agenda initiative” in September to revamp its development strategy. This initiative emphasized the concept of “co-creation,” whereby Japan and partners “set a joint strategy (priority areas, goals to be achieved in each area, and scenarios for the realization of cooperation), and on the basis of this strategy, through dialogue and collaboration with the partner countries, develop measures of support suited to each country and work together to realize these measures.”²⁸  This is particularly applicable to Japan’s development policy toward the ASEAN member states.

With these adjustments and “co-creation” as the keyword for the future of relations, Japan and ASEAN have developed an extensive implementation plan encompassing over 130 items. Now that the cooperative agendas are in place, the key for both Japan and ASEAN is to ensure they are effectively pursued. Consequently, in the short term, Japan’s domestic political uncertainty is unlikely to significantly impact its overall posture toward ASEAN, and this established framework is one of the factors that helps stabilize their relationship.

Looking ahead: Managing Internal and External Uncertainty

Ishiba faces the challenges of sustaining Southeast Asia’s positive perceptions toward Japan amid both domestic and external pressures. Despite the resilient nature of Japan-ASEAN relations, the recent loss of the LDP majority in the Lower-House complicates the decision-making process, hindering Ishiba’s ability to maintain consistent long-term foreign policies, as a stable domestic political foundation is crucial for such policies. Although Japan’s ASEAN policy has remained stable, Ishiba now needs to negotiate with opposition parties to secure the necessary budget to fulfill commitments promised in the 2023 ASEAN-Japan vision statement.

Externally, Japan would need to balance strengthening the US-Japan alliance with maintaining relations with ASEAN. On the one hand, the Trump administration may push for greater burden-sharing within alliances, including with Japan. While Japan has already promised to substantially enhance its defense capabilities by acquiring “counter-strike capabilities,” such as US tomahawk missiles, and aimed to increase its defense budget from 1% to 2% of GDP under the Kishida administration, Trump’s team could potentially make even larger demands.²⁹ If so, Ishida would face a hard choice: he could seek both public and political support to further increase the budget or engage in challenging negotiations with the United States.

The first option requires securing additional financial resources, but Ishiba has already pledged not to raise taxes for the defense budget, a stance that may be popular with an Upper-House election coming up in July 2025. The option of a tougher negotiating stance, risks straining US-Japan relations, potentially leading the Trump administration to bypass Japan in favor of engaging with not only other allies but also China, Russia, and North Korea. Either path would likely consume substantial political capital for Ishiba in addressing these challenges and not have sufficient resources to continuously strengthening relations with Southeast Asian states.  

Furthermore, Southeast Asia is undergoing domestic and foreign policy shifts in two important ways. First, leadership changes have taken place, with Singapore, Indonesia, Thailand, and Vietnam having new leaders in 2024, while Cambodia, Malaysia, and the Philippines went through leadership renewals starting from 2022. Although signs suggest general continuity in foreign policies, some shifts are likely. For example, following the Gaza conflict, Malaysia and Indonesia have begun to distance themselves from the United States and are increasingly engaging with non-Western coalitions. Their formal application to join BRICS, along with Thailand, demonstrate this diplomatic trend.

Second, ASEAN members are intensifying their pursuit of hedging strategies. While ASEAN has been the core of East Asian multilateralism, enabling its members to hedge against the risk of excessive reliance on great powers, the members are now exploring alternative strategic frameworks by engaging with diverse regional institutions and establishing minilateral frameworks. In addition to the emergence of non-ASEAN trilateral, minilateral, and multilateral frameworks, such as the Quad, AUKUS, and the IPEF, ASEAN faces growing challenges in retaining its centrality in regional multilateralism. If the association loses its diplomatic centripetal force in Southeast Asia and beyond, the institutional architecture of the Asia-Pacific could undergo critical changes. In this context, Japan needs to articulate a clear vision for the future of regional architecture in the Indo-Pacific, particularly defining ASEAN’s role—a critical factor yet to be fully addressed in Japan’s FOIP concept.³⁰

Southeast Asia’s “wait-and-see” posture toward Japan under the Ishiba administration does not guarantee diplomatic continuity. Southeast Asian states are closely observing Japan’s new foreign policy direction within the shifting regional and global strategic landscape. To sustain a positive relationship between Japan and Southeast Asia, the Ishiba administration needs to develop a comprehensive strategy that addresses the Indo-Pacific dynamics, including Southeast Asia, despite the significant challenges ahead.