What ASEAN Mediation Can and Cannot Do

Today’s increasingly contested geopolitical environment is placing new strains on ASEAN’s longstanding diplomatic practices. As one of the world’s most established regional organisations, ASEAN has traditionally relied on quiet diplomacy, non-interference, consultation and consensus-building to manage differences among its diverse membership. These principles also shape its approach to conflict mediation, which favours dialogue and facilitation over direct intervention.

This approach can be effective when parties are willing to engage, but whether it produces concrete results depends on their willingness to cooperate and, in some cases, on ASEAN’s ability to influence their behaviour. Three cases illustrate different constraints and are worth examining: Indonesia’s use of shuttle diplomacy since the 1980s shows the gap between agreement and implementation; the ASEAN Special Envoy mechanism on Myanmar shows the limits of political will; and the ASEAN Chair’s role in the recent Cambodia-Thailand conflict shows the importance of leverage.

Indonesia’s shuttle diplomacy is one of the clearest manifestations of ASEAN’s preference for quiet engagement. In the late 1980s, then Foreign Minister Mochtar Kusumaatmadja travelled to Ho Chi Minh City to bring Cambodian factions and external parties together, culminating in the Jakarta Informal Meeting. This series of meetings contributed to the 1991 Paris Peace Agreements, which marked the end of the Cambodian-Vietnamese War. A similar approach was used again in 2012, when ASEAN foreign ministers failed to issue a joint communiqué over disagreements on the South China Sea dispute. In response, then-Foreign Minister Marty Natalegawa travelled to several ASEAN capitals within 36 hours to engage member states individually. His efforts contributed to the adoption of the ASEAN Six-Point Principles on the South China Sea, which reaffirmed respect for international law and the peaceful resolution of disputes.

However, shuttle diplomacy has been less successful when agreement had to be turned into action. In 2011, Indonesia helped mediate the Thailand–Cambodia border dispute by facilitating talks and seeking to establish an ASEAN role in managing the conflict. Although both sides agreed in principle to ASEAN observers, the mission stalled over its terms of reference, particularly Thailand’s conditions on the withdrawal of Cambodian troops.

These experiences show both the promise and limits of shuttle diplomacy. It can preserve ASEAN unity and create space for a common position when formal consensus-building falters. But diplomatic convergence does not necessarily translate into implementation. Where parties cannot agree on the terms required to put an arrangement into practice, even sustained engagement can reach an impasse.

ASEAN’s Special Envoy mechanism on Myanmar illustrates a different kind of limitation. Since the 2021 coup, six successive ASEAN Chairs – Brunei, Cambodia, Indonesia, Laos, Malaysia and the current Chair, the Philippines – have each appointed a Special Envoy of the ASEAN Chair on Myanmar to advance the Five-Point Consensus. Yet independent assessments have frequently characterised the mechanism as more symbolic than substantive. Its effectiveness has been constrained by the annual rotation of the Chairmanship, which disrupts continuity and established relationships, and by the absence of mechanisms to ensure that commitments are met.

The deeper problem, however, lies in the nature of the conflict itself. Unlike an interstate dispute, in which the parties may seek to contain tensions while preserving the existing political order, Myanmar is a civil war between different intra-state actors over political power. The military has limited incentives to negotiate an arrangement that could weaken its hold on power, while resistance groups have increasingly developed their own political and territorial positions. Under these conditions, a mediator can facilitate dialogue, convey messages, calibrate language and keep channels of communication open, but it cannot persuade the involved parties in the civil war to accept a negotiated settlement.

The recent Cambodia-Thailand conflict illustrates a related but distinct constraint: the absence of leverage. Despite several attempts by Malaysian Prime Minister Anwar Ibrahim in Malaysia’s capacity as ASEAN Chair last year to facilitate dialogue and de-escalation between Cambodia and Thailand, ASEAN’s efforts were limited by its lack of political or economic tools to influence either side into changing its position. Late last year, China’s Special Envoy for Asian Affairs, Deng Xijun, travelled between Cambodia and Thailand as part of Beijing’s own shuttle diplomacy to facilitate de-escalation following renewed armed confrontation. China’s involvement came after a US-brokered peace arrangement had struggled to produce a durable settlement. While ASEAN could provide a forum for dialogue and encourage restraint, it lacked the political and economic leverage needed to meaningfully influence the parties’ strategic calculations. Beijing, by contrast, possesses significant economic, political and strategic relationships with both Cambodia and Thailand, giving it greater capacity to encourage de-escalation and sustain diplomatic engagement.

Taken together, these cases show that ASEAN’s ability to convene and facilitate does not automatically translate into outcomes. This gap is becoming more consequential as Southeast Asians expect ASEAN to respond more quickly to crises in an increasingly contested strategic environment. The 2026 State of Southeast Asia Survey by the ISEAS–Yusof Ishak Institute found that 34.7 per cent of respondents saw ASEAN’s slow response as an impediment to the region’s ability to respond to rapidly evolving political developments. Meanwhile, 32.2 per cent were concerned that ASEAN could become an arena for major-power competition, with Southeast Asian countries becoming proxies for competing external powers.

These experiences suggest four areas where ASEAN could strengthen its conflict-mediation capacity without abandoning the principles that underpin its diplomacy. First, ASEAN needs greater institutional continuity in mediation. Special envoys should not have to rebuild relationships and knowledge from scratch with each change of Chairmanship. A stronger support structure within the ASEAN Secretariat could preserve records and lessons, allowing successive Chairs to build on, rather than restart, existing processes.

Second, ASEAN should strengthen its capacity for preventive diplomacy. Much of the organisation’s diplomatic attention is mobilised only after violence has escalated. ASEAN could develop clearer procedures for identifying emerging tensions and deploying quiet diplomacy, fact-finding missions or good offices before disputes become harder to contain.

Third, mediation needs stronger follow-through. The 2011 Thailand-Cambodia experience shows that political agreement about a mechanism does not guarantee its implementation, while Myanmar demonstrates the difficulty of relying on commitments without effective means of monitoring progress. Despite challenging, ASEAN should at least place greater emphasis on agreed terms of reference, timelines, reporting arrangements and regular reviews when establishing such mechanisms. These measures would not require ASEAN to impose settlements, but they would make diplomatic commitments harder to leave unimplemented.

Fourth, ASEAN should be more deliberate about working with external partners when it lacks leverage. As the Cambodia-Thailand case shows, major powers may possess political, economic or strategic relationships that ASEAN lacks. Rather than treating external involvement as inherently at odds with ASEAN centrality, the bloc should establish clearer principles for complementary engagement, in which external actors provide resources, technical expertise or diplomatic leverage while ASEAN retains its convening and coordinating role. The objective should be for external involvement to support a regional process rather than displace it.

The policy challenge, therefore, is not to turn ASEAN into a conventional mediator with influence it does not possess, but to make better use of its existing diplomatic tools by making them more systematic, continuous and capable of producing follow-through. ASEAN’s strength lies in its ability to bring governments together and provide a politically acceptable regional platform. These roles may sometimes be underestimated, but they will only grow in importance as the region’s conflicts grow in complexity in the future.

Editor’s Note:
ASEANFocus+ articles are timely and critical insight pieces published by the ASEAN Studies Centre. The ASEAN@60 Special Edition series marks the organisation’s 60th anniversary in 2027 and highlights the key issues that will shape ASEAN and Southeast Asia as the organisation enters its seventh decade.