Abstract
This study examines Thailand’s move to advance the Ayeyawady–Chao Phraya–Mekong Economic Cooperation Strategy (ACMECS) within the existing institutional arrangements of the Mekong region, which collectively constitute an unfinished regional architecture, and takes this move as its case study. Utilising a case-study approach, which emphasises a close reading of the specific case, the research design broadly applies political realism—focusing on autonomy, independence, and relative gains—as an analytical lens for screening, interpretation, and contextualisation. The findings indicate that Thailand’s strategic calculations stem from internal determinants, such as the policy transfer back to the Ministry of Foreign Affairs after the 2014 coup, and external determinants, particularly the rapid involvement of China since 2014 through the establishment of the Lancang–Mekong Cooperation (LMC). China’s efforts to launch LMC sectoral bodies seek to reduce the political relevance of existing institutional arrangements; consequently, constructing ACMECS centrality may be viewed as a counterbalance to Chinese efforts to establish a Sinocentric order. Although strategically expedient, promoting ACMECS centrality could have unintended negative implications and requires sustained political will and support from both the Mekong nations and external powers.
1 Introduction
Today’s Mekong landscape teems with institutional arrangements—almost all top-down, intergovernmental multilaterals or minilaterals—whose origins can be traced both to the late Cold War era and to the rise of regional groupings following the Paris Peace Agreements signed in October 1991, which ended the Third Indochina War. Notwithstanding the dense web of regional institutions aimed at promoting peace, stability, and order, the Mekong region has again become a flashpoint in world politics, characterised by intensifying competition among major powers. Unlike armed conflicts in the past, present-day competition occurs through multilateralism and minilateralism (Singh and Teo, 2020).
Multilateralism generally refers to “the practice of coordinating national policies in groups of three or more states, through ad hoc arrangements or by means of institutions” (Keohane, 1990, p. 731). Regional multilateralism, in particular, describes “[the] formation of an institutionally-robust organisation in a region in which at least three states agree on a specific, rule-based agenda in order to mutually advance in given areas of cooperation” (Michael, 2013, p. 13). In contrast, minilateralism denotes “cooperative relations that usually involve [a select few countries], and are relatively exclusive, flexible, and functional in nature” (Singh and Teo, 2020, p. 2). Compared to regional multilaterals, minilaterals tend to include fewer members, are institutionally more informal, and are oriented towards functionally narrower goals (Singh and Teo, 2020). Further, minilaterals are described by some as “interest-based coalitions” (Tan, 2016, p. 5).
Five continental Southeast Asian countries—Cambodia, Laos, Myanmar, Thailand, and Vietnam (CLMTV)—constitute the Mekong region. Although these countries are members of the Association of Southeast Asian Nations (ASEAN), ASEAN’s multilateralism has not been sufficiently addressed, nor is it particularly relevant to Mekong issues, especially those concerning the Mekong River, a transnational water basin (Ho and Pitakdumrongkit, 2019). This may explain the proliferation of regional Mekong multilaterals and minilaterals across various issue areas, which typically diverge from the ASEAN-centric regional architecture, such as the ASEAN Regional Forum (ARF).
The Ayeyawady–Chao Phraya–Mekong Economic Cooperation Strategy (ACMECS), originally known as the Economic Cooperation Strategy, is a minilateral-turned-regional multilateral strategy launched by Thailand in April 2003. It was originally established as a minilateral venue allowing the Thaksin Shinawatra-led government to demonstrate its role as a donor, providing foreign aid to Cambodia, Laos, Myanmar, and Vietnam (CLMV), which were relatively less-developed economies. The ACMECS waxed and waned with the political cycle, determined predominantly, although not exclusively, by changes in leadership in Bangkok (Chachavalpongpun, 2010). Since the early 2010s, the ACMECS has become a pivotal foreign policy tool for Thai policymakers in navigating the Mekong’s multilateral and minilateral groupings.
Over the past decade, Thailand has actively developed the ACMECS amidst the spaghetti bowl phenomenon of regional multilateralism and minilateralism in the Mekong region. The orientation of Thailand’s Mekong policy has shifted towards using the ACMECS as a central mechanism in multilateral negotiations with neighbouring countries and external powers. The promotion of “ACMECS centrality”—defined as a state in which the ACMECS acts as a driving force within a web of multilateral institutions, thereby shaping, if not structuring, how nations engage on regional affairs while designing the context and organisation of a regional order—has recently been discussed in Bangkok’s policy circles (Poonthrigobol, 2020).
This article explores the context in which Thai policymakers began to discuss the promotion of ACMECS centrality. It then examines the determinants of Thailand’s strategic calculations and identifies its relevant interests in this regard. Finally, this article addresses the policy implications arising from efforts to establish the centrality of the ACMECS.
2 Materials and methods
This study relied upon both primary and secondary sources. The former predominantly comprised archival materials released by the Ministry of Foreign Affairs in Bangkok under the Official Information Act of B. E. 2,540 (1997) on several occasions, at the request of the second author. The Ministry’s press releases, speech transcripts, and reports were carefully reviewed, while writings authored by mid-level and senior officials were extensively vetted and read. Online materials, including official websites, were also surveyed. The latter mainly consisted of news articles published in media outlets such as the Bangkok Post, as well as scholarly publications and policy briefs.
A case-study approach was used to outline the overall research design. George and Bennett (2005) defined a case as “an instance of a class of events” (p. 17), whereas a class of events is “a phenomenon of scientific interest, such as revolutions, types of government regimes.that the investigator chooses to study” (George and Bennett, 2005, pp. 17–18). Grounded in this conception, the case-study approach is defined as “the detailed examination of an aspect of a historical episode to develop or test historical explanations that may be generalisable to other events” (George and Bennett, 2005, p. 5).
Importantly, the case-study approach is not monolithic. Specifically, a theory-guided case study method was employed. This method aims to interpret a single historical episode, but goes beyond inductive archival research and traditional historical studies. Case interpretations are structured and guided by a set of hypothetical assumptions that underlie the theory. Therefore, we focused on certain theoretically specified dimensions of the historical case, while some dimensions were deliberately omitted (Levy, 2008).
Nonetheless, we do not suggest that international relations theory should be entirely separate from diplomatic history. Rather, as “all historical accounts are inevitably theoretical” (Fulbrook, 2003, p. 12), the analytical synergy of the two disciplines could be beneficial (Fulbrook, 2003; Trachtenberg, 2006). In the present study, Thailand’s role in advancing ACMECS centrality was examined and interpreted through the broad lens of political realism, a doctrinal thought historically adopted by policymakers in Bangkok, as exemplified by the seminal work of former Thai top diplomat Arun Phanuphong (1971).
Although political realism was adopted as our analytical lens, it should be regarded as possessing a philosophical nature, or as comprising a set of hypothetical assumptions about world politics, rather than as a strict scientific theory. The common assumptions of political realism (Fox, 1985; Gilpin, 1984; Walt, 2002), irrespective of its various strands (e.g., neoclassical realism), can be listed as follows:
Political realism seeks to explain politics as it is, rather than as it ought to be.
Political realism is pessimistic about human conditions and progress, emphasising the continuity of history based on the inherently competitive nature of political life, which is motivated by honour, greed, and fear.
Political realism premises that international politics is anarchical in nature, as no authority exists above states to govern world affairs in the same manner as domestic politics.
Political realism postulates that international politics, as other forms of politics, deals with the scarcity of limited resources.
Political realism emphasises that states are the principal actors in international politics, each seeking to ensure their survival by pursuing power, security, or both.
Political realism posits that the gains of states are always relative; that is, the focus is on who gains more rather than on the absolute gains themselves.
Political realism argues that cooperation is inherently epiphenomenal.
Given the hypothetical assumptions of political realism stated above, it is sufficient to infer that autonomy, independence, and relative tangible and intangible gains are the nuts and bolts of foreign policy statecraft of all nations.
Employing political realism as an analytical lens, primary and secondary materials were read and interpreted in light of the common realist assumptions. These assumptions, that is, served to frame what should be focused upon and what could be omitted during the screening and interpretation of the materials. Political realism thus framed and guided the way in which the narration was developed.
For instance, rather than accounting for the ACMECS as a positive indication of cooperation among regional states, realism shapes a negative context. This perspective suggests that all parties involved in the ACMECS process seek relative gains, which match their national interests, such as maintaining autonomy by remaining unified amid major power influences. In essence, political realism served as the lens determining the colour of what the authors observed in this study.
3 Results and discussion
3.1 The Mekong’s spaghetti bowl
Arguably, the Mekong region has the largest number of existing institutional arrangements, whose areas of cooperation, mandates, and membership overlap intricately. For instance, while the Mekong River Commission (MRC)—the sole, rule-based international organisation governing the management of the Mekong River—has existed and operated since 1995, the Lancang Mekong Water Resources Cooperation Centre (LMC Water Centre) has been more recently established as a sectoral institution under the Lancang-Mekong Cooperation (LMC) umbrella to undertake similar, although not identical, tasks (Poonthrigobol, 2020). Consequently, the Mekong region now resembles a spaghetti bowl of multilateralism and minilateralism.
The spaghetti bowl of regional groupings has transformed into an intricate tapestry of overlapping chessboards, where strategic contests between major, middle, and small powers unfold at multiple levels. The term strategic refers to “the interactions of international politics, diplomacy, economics, and military power” (Baviera, 2016, p. 58). All these interactions, particularly following President Xi Jinping’s successful consolidation of comprehensive power within the Chinese Communist Party, have shaped the Mekong’s regional architecture. However, the construction of this architecture remains an ongoing process, and no state has succeeded in completing it.
Regional architecture refers to “…a combination of frameworks of cooperation and dialogue, institutional arrangements, and agreements and interactive processes among states in a region that help manage relations in that region” (Pinthong, 2015, p. 16). In other words, such architecture plays a pivotal role in shaping regional (institutional) order, which is typically based on common interests, norms, or rules and, in turn, influences the forms of dialogue and practices among regional states. Additionally, the centre’s institutional location within the regional architecture determines and demonstrates which voice is loudest in holding sway over multilateral and minilateral Mekong dynamics.
Currently, institutional arrangements in the Mekong region can be broadly classified into three main types based on their mandates, modalities, and memberships: (a) intergovernmental organisations, (b) “Mekong-only” multilaterals and minilaterals, and (c) “5 + 1” multilaterals and minilaterals. Intergovernmental organisations include the MRC and the Mekong Institute (MI). Mekong-only multilaterals include, inter alia, the Thailand-led ACMECS and the Vietnam-led CLMV Cooperation. Mekong-only minilaterals include the short-lived Emerald Triangle Cooperation, whose members comprise Cambodia, Laos, and Thailand.
The Mekong’s institutional arrangements, based on the 5 + 1 design, are either multilateral or minilateral. The five Mekong nations are members, plus one external power—often referred to as a development partner or dialogue partner—or an intergovernmental organisation (hereinafter, Mekong Plus One). The majority of these arrangements are minilateral and include (a) Mekong–Ganga Cooperation (MGC); (b) Mekong–Japan Cooperation (MJC); (c) Mekong–US Partnership (MUSP), formerly known as the Lower Mekong Initiative (LMI); and (d) Mekong–Republic of Korea Cooperation (MKC). Additionally, Russia has recently consulted with Mekong governments to launch the Mekong–Russia Cooperation (MRUC) in forthcoming years (Bunyavejchewin and Tungkeunkunt, 2023).
In contrast to the Mekong’s minilateral arrangements with other development partners, the 5 + 1 arrangement with China, referred to as the LMC by the Chinese and the Mekong–Lancang Cooperation (MLC) by the Mekong, is multilateral in nature because of its institutional design. It is a comprehensive umbrella encompassing various sectoral bodies, some of which are modelled as intergovernmental organisations. Notable examples include the LMC Water Centre and the Lancang–Mekong Integrated Law Enforcement and Security Cooperation Centre (LMLECC). Given its dense web of multilateral and minilateral mechanisms and cooperative projects, some diplomats refer to the LMC as a mini–Belt and Road Initiative (BRI) architecture (Tungkeunkunt and Bunyavejchewin, 2022).
The mini–BRI is institutionally linked to Sinocentric regional multilateral and minilateral arrangements, with the LMC at its centre. Almost all initiatives under the LMC umbrella have been associated with and sponsored by the Chinese-led Asian Infrastructure Investment Bank (AIIB)—a multilateral development bank that rivals the Japanese-led Asian Development Bank (ADB; Hameiri and Jones, 2018)—as well as related BRI institutions (Tungkeunkunt and Bunyavejchewin, 2022). China has sought to complete the construction of the LMC-centric architecture and move decision-making authority regarding the region’s key issues, such as Mekong River management, from other institutions (e.g., MRC) under the LMC umbrella (Tungkeunkunt and Bunyavejchewin, 2022). China’s ultimate aspiration is clear: to establish a regional order under its leadership in which the roles of other external powers, notably the United States and Japan, are marginalised (Busbarat et al., 2021).
The Sinocentric mini–BRI represents a new comprehensive mechanism that Beijing has sought to construct as a substitute for the incomplete architecture established by CLMTV nations. In addition to the centrality of the LMC and its sectoral bodies, the remaining multilateral and minilateral arrangements in the Mekong region are CLMTV-centric, albeit to varying extents. For example, within the Mekong Plus One minilaterals, the capitals of continental Southeast Asia had relatively stronger voices in their formation and processes. In the case of South Korea’s MKC, Bangkok and other capitals successfully negotiated with Seoul to drop its plan to include political security as a minilateral area of cooperation during its formation (Suporn and Bunyavejchewin, 2024). However, they failed to achieve this in the case of LMC (Tungkeunkunt and Bunyavejchewin, 2022).
The above illustrates the spaghetti bowl of multilateral and minilateral arrangements in the Mekong region. It highlights the parallel efforts undertaken by CLMTV countries, particularly Thailand and Vietnam, alongside China, to shape the regional architecture, both seeking to assume a central role. Nonetheless, China’s presence in the region’s institutional landscape has expanded rapidly in recent years, rendering the centrality of the LMC more pronounced. The successful establishment of LMC centrality has been an unfavourable scenario for the CLMTV countries, potentially affecting their national interests. Consequently, pressure has mounted on Bangkok as a middle power to prevent this scenario from materialising.
3.2 Thailand and the birth of ACMECS
Thai foreign policy has been guided by three dimensions of concern: (a) territorial integrity and security; (b) economic prosperity; and (c) status, defined in terms of reputation, image, and credibility (Bunyavejchewin et al., 2022). The relative importance of each concern in a foreign-policy formulation depends on the specific context at a given point. For instance, during the Indochina Wars, concerns for territorial integrity and security assumed greater significance in the formulation of Thailand’s foreign relations with continental Southeast Asian nations. Meanwhile, concerns about status assumed considerable significance in Thailand’s efforts to establish the ACMECS in 2003 (Chambers and Bunyavejchewin, 2021).
The ACMECS, whose members are CLMTV countries, was conceived and established by the Thaksin administration in the early 2000s following the post-1997 Asian financial crisis. The Thai economy, along with other East Asian economies, experienced sustained recovery, and the economic situation largely returned to normal. In this context of economic recovery, Thaksin’s Thai Rak Thai (TRT) party achieved a landslide victory in the 2001 general election, attributable to its populist campaigns and pledge to restore Thailand’s prominence, both domestically and internationally.
The Thaksin government sought to assert Thailand’s leadership in regional multilateralism and minilateralism on several levels. The establishment of the ACMECS provided a platform through which Thailand could demonstrate its regional leadership in the Mekong region, repositioning itself as a new donor country and dispelling its image as a recipient nation (Chachavalpongpun, 2010). Similarly, Thailand’s Mekong policy under the Thaksin government sought to distinguish it from its neighbours, namely the CLMV countries. Diplomatically, Bangkok carefully avoided any actions that might foster the discourse of CLMTV in foreign affairs, as Thailand regarded itself as a foreign aid donor, whereas the other countries (i.e., CLMV) were perceived as a club of recipients. This was manifested in the reluctance of policy elites in Bangkok to link the ACMECS with CLMV Cooperation and attend the CLMV Summit in the mid-2000s (Ministry of Foreign Affairs, 2005). Therefore, status factors come into play.
Thailand did not initially invite Vietnam to join the ACMECS. Arguably, this was because Bangkok perceived Hanoi as a rival in the Mekong region. Given that there could only be one hegemon in an institutional arrangement, by excluding Vietnam, Thailand could enjoy its sole hegemonic status without competition (Ministry of Foreign Affairs, 2005). Even so, Thailand approved Vietnam’s request to join the ACMECS as a full member 1 year later. This decision was probably intended to mitigate criticisms and suspicions from neighbouring countries that Thailand sought to realise the Golden Peninsula (Suwannaphum) vision by establishing a region with Thailand at its centre (Chachavalpongpun, 2010).
Since the 2006 coup d’état in Thailand, the ACMECS has been beset by domestic political instability characterised by frequent changes in political leadership in Bangkok. Thailand’s role in ACMECS activities diminished when anti-Thaksin factions assumed power, such as during the tenure of former Prime Minister General Surayud Chulanont (Chachavalpongpun, 2009). This led other members and external stakeholders (e.g., development partners) to face uncertainties regarding the future of the regional multilateral, which, in turn, resulted in the ACMECS losing its political momentum.
Debatably, the ACMECS has evolved beyond the scope of a minilateral. This development is attributable to its institutional design, which has emulated that of ASEAN, leading some to refer to ACMECS as a mini-ASEAN (Sucharithanarugse, 2006). As a result, despite fluctuations in activities, the ACMECS process—particularly regular meetings at multiple levels, including summits—has become institutionalised. This enables the arrangement to fairly withstand strategic downturns, albeit sometimes barely, resulting from both Thailand’s domestic politics and the rising geopolitics of the Mekong region.
The ACMECS has experienced periodic turbulence owing to regime changes and recurrent political instability in Bangkok. The Mekong multilateral initiative, originally introduced by Thaksin, was restored and revitalised by the military-backed anti-Thaksin regime led by General Prayut Chan-o-cha, who overthrew the Yingluck Shinawatra Government in May 2014. Both internal and external determinants contributed to this unexpected development.
3.3 Internal and external determinants
Internal and external determinants compelled the military-installed Prayut government to utilise the ACMECS, a legacy of Thaksin, as a major element of its institutional statecraft in navigating both multilateralism and minilateralism in the Mekong region. Domestically, 1 year after the 2014 coup, following a series of national embarrassments (Bunyavejchewin et al., 2022), military leaders eventually recognised that diplomacy and international affairs required highly experienced technocrats to manoeuvre effectively. The foreign-policy formulation was subsequently returned to the Ministry of Foreign Affairs under Don Pramudwinai, a veteran diplomat who had spent his entire career within the Ministry. This transition was critical, as the making and manoeuvring of Thai foreign policy has become highly institutionalised, residing almost entirely within the Foreign Ministry over the past five decades (Chachavalpongpun, 2010). Officials within the Ministry translated Thaksin’s vague idea of the ACMECS into practice.
Since 2013, China has repositioned itself as a fully-fledged, “normal” major power, unilaterally claiming rights and privileges equivalent to those of the United States (Zeng, 2016). These include the right to establish a sphere of influence over certain regions, particularly continental Southeast Asia, which it considers its own backyard (Busbarat et al., 2021). Furthermore, Beijing has called for reforms to the international financial governance structure to accommodate the interests of emerging economies. Chinese efforts are best exemplified by the creation of the AIIB, a financial source for the multi-layered Sinocentric BRI architecture, provisionally prepared for the anticipated China-led order at multiple levels.
Regionally, as elsewhere, China has acted “fast-and-furious” in demanding and pressuring the CLMTV nations to support the launch of the LMC—a mini-BRI in the Mekong region—and insisted that its goals proceed at a breakneck speed (Ministry of Foreign Affairs, 2015a). The Chinese demand was reiterated in the statement of Premier Li Keqiang: “China will respond positively and explore the establishment of a Lancang-Mekong River dialogue and cooperation mechanism. We plan to hold a foreign ministers’ meeting next year [2015]” (Ministry of Foreign Affairs, 2015b). This was despite the fact that the LMC had only officially formed in April 2014 (Ministry of Foreign Affairs, 2015c).
The LMC was established upon a standard structural blueprint, characterised by a “hub-and-spoke” design in which the main regional multilateral organisation is at the core, while its schemes and sectoral bodies are at the spokes, for Chinese-led regional multilateralism (Jakóbowski, 2018). Typically, all of these are institutionally linked with BRI institutions, such as the AIIB. This was similar, although not identical, to other Sinocentric regional multilaterals elsewhere, such as the China-CELAC Forum in Latin America and the Forum on China-Africa Cooperation in Africa (Jakóbowski, 2018).
During the formation of the LMC, the Chinese exerted pressure on the Mekong governments on numerous occasions, aiming to expedite the LMC process and secure consensus from the Mekong governments regarding China’s preferred institutional design. These instances included the incorporation of political and security issues as a key pillar of LMC cooperation. Thailand and Vietnam were subject to considerable political pressure from China to comply with Chinese demands. For instance, both countries strongly objected to China’s intention to incorporate political and security issues, as this would overlap with the ASEAN-centric ARF. Nevertheless, they were unsuccessful as the Chinese did not compromise on this point. In light of these developments, Bangkok and Hanoi agreed that both capitals, along with other Mekong governments, should consult each other before negotiating with Beijing (Ministry of Foreign Affairs, 2015d). Such consultations could be conducted through ACMECS meetings in which no external powers, including China, were members (Chambers and Bunyavejchewin, 2019; Poonthrigobol, 2020).
More importantly, China’s central agenda has been explicit from the outset: to transfer decision-making authority regarding key issues, particularly water resource management, from pre-existing arrangements to the LMC, thereby rendering the Mekong’s regional architecture Sinocentric. For example, the LMC Water Centre, located in Beijing, was designed to limit and diminish the role of the MRC in regimes related to Mekong River governance (Chambers and Bunyavejchewin, 2019; Poonthrigobol, 2020). Moreover, China transposed Chinese-led cooperative projects from pre-existing arrangements, most notably from the Greater Mekong Subregion Economic Cooperation Programme (GMS), to the LMC (Busbarat et al., 2021). Furthermore, China established the LMC Special Fund to sponsor projects under the umbrella of LMC. This has precluded non-Chinese development banks such as the ADB from participating in these projects, and rendered pre-existing multilateral mechanisms less relevant in development cooperation.
At a broader level, China has reportedly attempted to undermine ASEAN centrality by unilaterally establishing mechanisms without securing a consensus from ASEAN members. Rather than seeking ASEAN consensus, the Chinese government invited individual ASEAN countries to attend meetings on self-established mechanisms, subsequently citing such attendance as evidence of ASEAN’s approval for launching these mechanisms. These included the ASEAN–China Ministerial Dialogue on Law Enforcement and Security Cooperation, which is linked to BRI institutions (Ministry of Foreign Affairs, n.d.).
China has established the LMC and its sectoral bodies within the Mekong region, linking them with a wider BRI architecture, notably the AIIB. Simultaneously, the Chinese government has sought to render other arrangements from the MRC to the Mekong Plus One minilaterals that are increasingly irrelevant and marginalised. Meanwhile, in Southeast Asia, China has attempted to undermine the centrality of ASEAN by unilaterally introducing BRI-linked schemes within ASEAN. In essence, China has endeavoured to replace the existing network of regional Mekong multilaterals and minilaterals— an unfinished regional Mekong architecture, i.e., a condition wherein no multilateral institution is able to considerably, if not nearly entirely, dictate the context and organisation of a region’s order—with a mini-BRI architecture, represented by the centrality of the LMC.
These external developments have substantially influenced how Thai policymakers in the Foreign Ministry perceive China’s LMC diplomacy and its strategic ambition to establish a Sinocentric architecture in the Mekong region. If successful, this would undermine the relevance of pre-existing multilaterals (e.g., MRC) and minilaterals while marginalising the roles of other external powers. Consequently, it has prompted policymakers in Bangkok to prioritise developing strategies to address this potential scenario. By linking and synergising the Thai-initiated multilateral with other regional Mekong arrangements (e.g., Mekong Plus One minilaterals) and partner countries, the ACMECS has been positioned as central. This has emerged as a key strategy to counterbalance China’s strategic expansion exerted through Chinese-led regional multilateralism (Poonthrigobol, 2020).
3.4 Achieving ACMECS centrality
The external environment, characterised by China’s rapid advancement of the LMC process since 2014, has had a profound effect on Thailand’s strategic calculations to revitalise the ACMECS. This effort aims to position the ACMECS, the homegrown multilateral organisation, as the focal point of Mekong multilateralism and minilateralism (Jariyadham, 2022). This Thai strategy aims to offset China’s expanding presence, manifested through the growing LMC-centric architecture, within the region’s institutional landscape. Over the past decade, ACMECS centrality has been gradually constructed, particularly after 2018, when Thailand was the ACMECS Chair (Poonthrigobol, 2020).
The emerging centrality of the ACMECS has been exemplified through activities newly introduced by the Thai initiative, such as the current ACMECS Master Plan (2019–2023). The Master Plan operationalised the ACMECS pillars of cooperation, known as the 3S, namely: (a) Seamless Connectivity, (b) Synchronised ACMECS Economies, and (c) Smart and Sustainable ACMECS (Poonthrigobol, 2020). Thailand also proposed the introduction of Joint Development Plans (JDPs) between the ACMECS and its Development Partners (DPs), thereby concretising and enhancing development cooperation between the two parties (Ministry of Foreign Affairs, 2022a). As of May 2025, the ACMECS DPs include Australia, China, India, Japan, South Korea, the United States, and New Zealand, whereas Israel and Switzerland are on the waiting list (Chongkittavorn, 2023). By signing JDPs with individual DPs, cooperation and collaboration can be encouraged more meaningfully and systematically. Apart from the ACMECS DPs, Thailand has sought to link the ACMECS with the Mekong Plus One minilateral frameworks. This effort was evident in the cases of Japan’s MJC and South Korea’s MKC, in which the Thai party reiterated the importance of the synergy between these minilaterals and the ACMECS (Ministry of Foreign Affairs, 2015e).
Thailand brought forward the establishment of the ACMECS Development Fund (ACMDF). It was designed to serve as a financial mechanism for funding cooperative projects under the ACMECS, particularly ACMECS Prioritised Projects. The initial amount of the ACMECS fund was set at USD 500 million, with Bangkok contributing USD 200 million as an initial commitment. Other members would contribute to the ACMDF in amounts proportional to their gross domestic product (GDP). All member countries are required to contribute to the ACMDF in order to enhance participation and unity (Poonthrigobol, 2020). The ACMECS DPs have been encouraged to voluntarily contribute funding. In 2022, Japan voluntarily contributed nearly 1.4 million US dollars to the ACMDF to sponsor the ACMECS Branding Project (Ministry of Foreign Affairs, 2022b).
In addition to the ACMDF, the Thai government has proposed the establishment of the ACMECS Secretariat to facilitate and coordinate dialogues and projects. The ACMECS Interim Secretariat was established in 2024, and it is located at the Ministry of Foreign Affairs in Bangkok. The Secretariat has been assigned the following functions: (a) policy, planning, and coordination; (b) conference services; (c) project management; and (d) communication strategies. The MI, located in Khon Kaen, Thailand, has supported the work of the Secretariat as a back office (Ministry of Foreign Affairs, 2024a). Kanwana Hemkamon, a Thai diplomat, was appointed as the Secretariat’s first director.
Since the mid-2010s, Thailand has arguably been successful in injecting political momentum into the ACMECS, demonstrating progress regarding important issues (Jariyadham, 2022). Recently, the ACMECS appears to have gained further political momentum, as the Thai government tabled and incorporated the Concept Note on Water Resources Management in the Mekong Sub-Region as an annexe to the current ACMECS Master Plan. This Concept Note provides guidelines for addressing water resource management and enhancing cooperation over this issue (Ministry of Foreign Affairs, 2024b). This represents a critical step for Thailand and other lower Mekong nations, as it enables consultations on the Mekong River to establish common ground before engaging in negotiations with China and other organisations, such as the LMC Water Centre, dominated by the Chinese. Moreover, it signalled to the Chinese-led LMC Water Centre the need to facilitate greater cooperation, particularly in sharing water-level data, which it reportedly did not provide to riparian countries in need.
Thailand could not concretise ACMECS centrality alone. This required common ground shared by other Mekong capitals. Therefore, Bangkok had to approach the CLMV countries to achieve this goal. In contrast to the mid-2000s, Thailand could no longer deal with its neighbours in an asymmetric manner, particularly through donor-and-recipient practices. In the 2010s, Thailand possessed neither as much diplomatic capital, nor the leverage it had a decade earlier. Thus, Bangkok had to promote the discourse of CLMTV, which it had avoided approximately 10 years earlier; otherwise, it had no cards left in hand to play with China. Hence, Thailand needed to engage with other continental Southeast Asian states on an equal footing to gain support for building the centrality of the ACMECS.
From the perception of the Thai Ministry of Foreign Affairs, the centrality of ACMECS can also be upheld by its merits. First, the ACMECS is an indigenous Mekong cooperation that is both open and neutral. Second, it provides a strategic forum for regional development cooperation, demonstrating a strong commitment to reducing disparities and promoting sustainability in the Mekong economies, while avoiding political issues. Third, the ACMECS is a multilateral arrangement that can lead to the comprehensive integration of the ASEAN Community (Poonthrigobol, 2020). While it remains too early to state that ACMECS centrality, in its current form, is sufficient to be at the centre of Mekong’s regional architecture, ACMECS’ progression is clear.
3.5 ACMECS centrality as a device of strategic expedience
China’s LMC diplomacy, directly involving itself in the Mekong’s multilateralism and minilateralism through the construction of the Chinese-led LMC architecture, has strategically rendered pre-existing institutional arrangements less relevant, albeit to varying degrees. Thailand’s promotion of the ACMECS centrality can be regarded as a balancing strategy to decelerate the LMC process and its expansion. The ACMECS has also become a venue for seeking a common stance among the Mekong capitals, thereby strengthening their shared voices in negotiations with major powers, especially China. Furthermore, it serves as a forum in which all DPs engage in dialogue with ACMECS members on an equal footing. Meanwhile, it seeks to link the ACMECS schemes with the Mekong Plus One minilaterals. Collectively, these efforts have established, although not yet completed, the ACMECS as a central connecting point at which cooperation, collaboration, and coordination intersect.
Thailand’s Mekong policy, with ACMECS as a policy tool of institutional statecraft, has potentially achieved its principal objectives. These include, above all, decelerating the Chinese-led LMC process and expansion, while repositioning the Thai-initiated multilateral towards the centre of the region’s architecture to gain political momentum. This has also helped pre-LMC arrangements retain their relevance in the context of intense geopolitics. The recent broadening and deepening of cooperation to include issues related to the Mekong River represents a crucial step for Thailand and the lower Mekong nations, thereby adding value to the ACMECS, as it can serve as a platform for dialogue on these specific matters, similar to the MRC and LMC Water Centre.
The centrality of ACMECS has served as a tool of strategic expedience. At the very least, it can be considered a spoiler, temporarily slowing the Chinese-led LMC process by injecting political momentum into the Thai homegrown arrangement and bringing external powers (i.e., ACMECS DPs), particularly Japan and the United States, together to balance the rapidly growing influence of China on Mekong affairs (Bunyavejchewin and Buddharaksa, 2024). Such manoeuvres have also produced negative repercussions. By consolidating ACMECS centrality, other multilaterals operating under similar regimes have been adversely affected. For example, while the incorporation of Mekong River management into the ACMECS areas of cooperation is strategically advantageous for Thailand, adverse effects are felt by the MRC as ACMECS can offer a similar platform, thereby inevitably rendering the MRC politically less relevant.
Considering the adverse effects, Thailand and other like-minded Mekong countries must weigh the potential relative damages and disadvantages resulting from the elevation of ACMECS centrality, particularly considering the Mekong’s institutional landscape and their national interests. For instance, Thailand had long benefited from China’s “carrots,” but then received the “stick” in the form of deliberate shaming when it failed to comply with China’s demands in 2017. This was not merely due to the slow progress of the Sino-Thai high-speed rail projects (Busbarat, 2017); it was also attributable to Bangkok’s spoiler role in obstructing the LMC process (Bunyavejchewin and Buddharaksa, 2024). Advancing the centrality of the ACMECS may antagonise the Chinese government, resulting in more “sticks” from Beijing. Strategically, this underscores the necessity for more active roles by other external powers such as Japan to contain and deter China’s potential assertiveness and its orbits.
Constructing the ACMECS centrality is an act of strategic expediency. Although it has appeared effective in counterbalancing China’s efforts to mobilise the Chinese-led LMC and position it at the centre of the Mekong’s regional architecture, thereby rendering it Sinocentric, the establishment of ACMECS centrality requires the political will of both regional states and external major powers in the long run. Unfortunately, this support cannot be guaranteed. For example, under Donald Trump, the United States adopted an unpredictable stance regarding whether Washington wished to maintain its hegemony and contain China. Besides, the Mekong’s middle powers, Thailand and Vietnam, continue to perceive each other as rivals. A stronger ACMECS centrality would weaken the Vietnam-led CLMV Cooperation. Accordingly, ACMECS centrality may not be the preferred choice for Hanoi.
Regardless, for Bangkok, ACMECS centrality currently appears to be strategically expedient in maintaining the pertinence of the incomplete Mekong architecture and its regional order.
4 Conclusion
The centrality of the ACMECS was constructed by Thailand, together with like-minded countries, amidst the spaghetti bowl phenomenon of multilateral and minilateral in the Mekong region. This so-called spaghetti bowl may be regarded as the region’s unfinished regional architecture, centred on CLMTV countries, albeit to varying degrees. The current architecture, comprising primarily water-governing bodies, Mekong-only institutional arrangements, and Mekong Plus One minilaterals—has, to some extent, been CLMTV-centric, such that the voices of the Mekong capitals cannot be disregarded.
Nevertheless, since China, represented by the central Chinese government, began to engage directly in regional Mekong groupings through the establishment and rapid expansion of the LMC, Thailand has viewed this development with suspicion, interpreting it as a Chinese domineering effort to build a Sinocentric regional architecture—a mini-BRI in the Mekong. This includes the creation of the Chinese-led LMC Water Centre, a multilateral designed to perform functions similar to those of the MRC, a legally binding organisation managing the Mekong River. Within this context and the external environment, Thailand was prompted to pursue the policy option of shaping ACMECS centrality.
Internal determinants also affected bringing the ACMECS into play in Thailand’s institutional status. The decision in 2015, when coup leaders returned the foreign policy formulation and decision-making authority to the Foreign Ministry, was a turning point that allowed Thailand’s diplomacy and international affairs to return to the conventional course. To navigate Chinese-led regional multilateralism, pivotal around the LMC, policymakers in Bangkok decided to restore and revitalise the ACMECS, even though it was initiated by Thaksin Shinawatra, a symbol of the political faction opposing the Prayut government. Namely, after 2015, Thai foreign policy directions were steered by the Foreign Ministry, whose strategic calculations were pragmatic enough to utilise all potentially leveraged policy tools. This established the context for ACMECS centrality.
Thailand’s role in the context of ACMECS centrality has been to position the ACMECS as the centre of the Mekong’s unfinished regional architecture to the greatest extent practicable, and to preserve the architecture’s pertinence while maintaining regional order in the face of the rapidly expanding LMC centrality promoted by China. Even if ACMECS centrality is strategically expedient in institutionally balancing the Chinese expansion, it may have the unintended effect of rendering existing institutional arrangements less relevant. Constructing ACMECS centrality also demands the political will and support of CLMV nations and external powers, such as the United States and Japan. The failure to secure such support may result in a loss of political momentum. Nevertheless, Thailand’s role in promoting ACMECS centrality as a key component of the Mekong’s regional architecture appears to be effective, at least at present.
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Author contributions
TS: Writing – original draft, Methodology, Investigation, Conceptualization, Writing – review & editing. PB: Conceptualization, Investigation, Funding acquisition, Resources, Methodology, Writing – original draft, Writing – review & editing. KT: Writing – original draft, Supervision, Writing – review & editing.
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The author(s) declared that financial support was received for this work and/or its publication. This work was supported by the Korea Foundation (2025 Support for Policy-Oriented Research Program).
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Summary
Keywords
ACMECS, ACMECS centrality, China, Lancang–Mekong cooperation, Thailand
Citation
Suporn T, Bunyavejchewin P and Tungkeunkunt K (2025) Thailand’s role in the context of ACMECS centrality: (re)constructing the Mekong’s regional architecture. Front. Polit. Sci. 7:1698498. doi: 10.3389/fpos.2025.1698498
Received
03 September 2025
Revised
02 December 2025
Accepted
03 December 2025
Published
18 December 2025
Volume
7 - 2025
Edited by
Sanyarat Meesuwan, Mahasarakham University, Thailand
Reviewed by
Ying-kit Chan, Leiden University, Netherlands
Chaowarit Chaowsangrat, Rajamangala University of Technology Rattanakosin, Thailand
Updates
Copyright
© 2025 Suporn, Bunyavejchewin and Tungkeunkunt.
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*Correspondence: Poowin Bunyavejchewin, pw6@staff.tu.ac.th
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