How to avoid ambiguity becoming a ‘solution’ for the South China Sea

The 18th International Conference on the South China Sea closed in Hanoi after two days of discussion starting October 7, with the Code of Conduct (COC) present throughout, even in tea-break conversations. In the presence of diplomats from most foreign embassies in Hanoi, and with participation of Chinese scholars in most panels, the Track 1.5 dialogue saw the COC mentioned in the careful phrasing of officials and scholars to avoid unnecessary tension.

After decades of inconclusive talks, participants did not expect to hear any bold, breakthrough suggestions for how to finalise the COC anytime soon. A Cambodian participant sharply stated that China does not want the COC. Indeed, there is a common view that South China Sea diplomacy is loud in rhetoric but weak in practice.

The COC has become an indispensable symbol that embodies a commitment to peaceful management, even as the geopolitical agenda moves on to other matters. Although a COC is considered “elusive”, the region increasingly refers to the COC as if it already exists as a stabilising order—a curious case of talks about an order becoming a quasi-order itself.

Until recently, COC negotiations were said to be entering a decisive phase, and that there was real momentum behind that claim. Yet the core disagreements that have shaped the process for years remain unresolved. The real test of the COC is not whether leaders talk about it, but whether they are willing to reduce ambiguity and constrain behaviour, without pretending the document can resolve disputes over sovereignty.

The COC deserves the effort. Its value never lay in the resolution of competing maritime boundary claims, which it plainly cannot do. Its true value lies in three more modest functions. The first is to build confidence among claimants. The second is to prevent crises from escalating. The third is to enable pragmatic cooperation at sea.

A workable COC can establish predictable rules for encounters among coast guards, fishing fleets, and survey vessels. It can create channels for communication when incidents occur and make the expected norm one of restraint. For fishermen, coast guard crews, and naval officers, these are the factors that determine whether a collision becomes an incident or a crisis. The COC needs to provide conflict management even as the settlement of sovereignty disputes remains elusive.

However, several unresolved questions interpose between diplomatic label and usable regime. The first is geographic scope: Where, precisely, would the code apply, and does it cover contested features and waters around them? China does not want to include the disputes over the Paracel Islands in the COC. But Vietnam’s sovereignty claims over the Paracel Islands—in what it terms the East Sea--are legitimised by the United Nations Convention on the Law of the Sea (UNCLOS). Furthermore, China’s armed  takeover of the Islands from Vietnam in 1974 was clearly illegal under international law. The second is legal force: Is the COC legally binding, or merely a political declaration that can be set aside when convenient? The third is self-restraint: What activities, from construction and militarisation of land features to harassment of vessels, would parties commit to avoiding, and how clearly are they defined? The fourth is oversight: Who monitors compliance and how implementation is reviewed. The fifth is dispute settlement: What happens when parties disagree about whether the code has been violated? A text that leaves these questions open can be signed with ceremony but will change truly little.

Why, after more than two decades of effort, do these questions remain open? Answering them became even more challenging after China rejected the South China Sea Arbitral Award 2016. Part of the reason is that ambiguity serves interests. For China, vagueness preserves freedom of action, limits external scrutiny, and keeps the negotiation anchored in a bilateral, regionally managed framing rather than one shaped by outside legal or political pressure. For ASEAN, ambiguity is also tolerated, and imposed from outside. A consensus-based grouping with divergent claimants and divergent relationships with Beijing, it finds that unresolved language preserves room for manoeuvre and avoids open confrontation, both internally and with China. Delayed conclusion of the COC, in this sense, is not simply failure. It is a rational equilibrium, one in which no party pays the immediate political cost of precision. The danger is that this equilibrium can persist indefinitely, with the COC cited as evidence of progress while conditions at sea evolve in ways the text never touches.

What, then, would count as success? It should be defined modestly but concretely. An “effective and substantive” COC would coincide with fewer incidents at sea, not merely fewer speeches about them. It would set clearer rules of conduct, so that behaviours can be assessed against an agreed standard rather than contested interpretation. It would support better maritime cooperation, from search and rescue to environmental protection and fisheries management, giving claimants practical stakes in the arrangement. It would include mechanisms that survive tension and crises, such as communication channels, review processes, and procedures for handling disputes, which continue to function when relations are strained, which is precisely when they are needed.

None of this requires heroic assumptions. Parties are expected to accept that a code with defined scope, meaningful commitments and some form of oversight will constrain them as well as their counterparts. That is a real political cost, and it explains the slow pace. But the alternative is a code whereby talks are celebrated as an achievement while behaviour is left untouched, which would be worse than no code at all, because it would lend false reassurance to a contested sea.

The Hanoi conference showed that the COC retains its place in the regional conversation in different forms and through different channels. The task now is to ensure it earns that place in practice.

Nguyen Hong Hai is an Assistant Professor in the College of Arts and Sciences at VinUniversity, specialising in politics and international relations.