How should Southeast Asia resolve its unsettled maritime boundaries? This book represents one of the most recent analytically comprehensive studies which identifies Southeast Asia’s unresolved land and maritime boundaries, the underlying historical geopolitical tensions, and potential approaches to dispute settlement. It succinctly illustrates several contentious maritime areas claimed by multiple Southeast Asian states.

A general theme that emerges from the book is that disputes over maritime features and boundaries are extremely sensitive, and that Southeast Asia is “replete with territorial disputes” (p. 91). Some are traceable to colonial “shatterbelts”. Tiny features in the sea can be used as symbols of highly politically charged assertions of sovereignty (p. 169). Sovereign rights over natural resources, particularly fish, incense strong political views (p. 31), while hydrocarbons in the continental shelf of a less developed Southeast Asian state may be fiercely contested as a critical source of economic development (p. 238). Navigational safety and security could also be high stakes for states dependent on maritime trade routes, and trigger the involvement of larger political powers including India, Russia, the UK, and the US.

Delimitation becomes exponentially complicated where there exist land or maritime tri-points. Bangladesh instituted proceedings against both Myanmar and India at the same time. At least four of the ten states in the Association of Southeast Asian Nations [ASEAN] lay claim to some of the features in the Spratly Islands. Cambodia and Thailand have had historical border skirmishes. Parts of the Gulf of Thailand are contested by Cambodia, Thailand, and Vietnam (p. 126). The dispute between Singapore and Malaysia over Pedra Branca (p. 84) reopened in 2017 when Malaysia applied for a revision of the International Court of Justice [ICJ] judgment on the basis of undiscovered evidence. Unresolved boundaries linger since Indonesia’s exclusive economic zone and continental shelf could potentially extend to this overlapping area.

What becomes evident from this book is that, while some boundaries are complicated by peculiar geography, many are made more complex and intractable because they are not simply bilateral, but involve a third state. Multiparty adjudication of boundaries requires an enormous amount of political will (p. 154). All the relevant parties would have to give their consent to international adjudication by a single court or tribunal. On the other hand, bilateral adjudication may fail to properly settle the dispute where third parties’ interests are concerned. Hence ASEAN’s effectiveness as a regional organization to resolve certain boundary disputes in Southeast Asia is demonstrated in the organization’s handling of the disputes in relation to the Preah Vihear Temple case and the South China Sea arbitration.

This book recognizes that overlapping entitlements are indeed “existential” disputes, and examines how ASEAN can serve as a forum for multilateral conflict resolution, including multitrack diplomacy (p. 204) and joint development (p. 244). In so doing, it sets the scene for a serious inquiry into the development of a dispute settlement mechanism that will be suitable for Southeast Asia. In addition to the 2002 Declaration on the Conduct of Parties in the South China Sea led by ASEAN, multiparty conciliation either under the 2010 Protocol to the ASEAN Charter on Dispute Settlement Mechanisms for intra-ASEAN boundaries, or the United Nations Convention on the Law of the Sea [UNCLOS] Annex V for disputes involving non-ASEAN third-party states, could be useful for two reasons: its non-binding result and its flexibility in allowing multistate participation.

Multiparty conciliation offers a “regional process” that could revive failed joint development efforts (p. 244). Timor Leste expeditiously reached agreement with Australia on boundary delimitation and resource-sharing within just seven months of conciliation. The flexibility of procedures could bring into play interests of other non-state stakeholders such as regional organizations, environmental organizations, and oil companies (p. 261). Conciliation of environmental protection disputes in areas of unresolved territorial or maritime boundaries could build trust between disputing Southeast Asian states, which could form the foundations of a “constitutional order” (p. 239) for increased co-operation in provisional arrangements such as joint development or consensus to enter into negotiations. As the Chairman of the Timor Leste / Australia conciliation commission advised: “Conciliation is a marathon, not a sprint.”Footnote ¹