The 2016 South China Sea Arbitration Award Did Not Fail

10 years after the South China Sea Arbitration Award, the most important question is no longer whether China complied with the ruling. It plainly did not. The more important question is whether the Award has nevertheless changed the strategic and legal landscape of the South China Sea (SCS). Increasingly, the answer is yes.

When the arbitral tribunal issued its landmark decision on 12 July 2016, many expected a decisive turning point, not only for the dispute, but also for the authority of international law in the SCS. The Award invalidated China’s expansive “historic rights” claims within its ‘nine-dash line’, clarified the status of disputed islands, rocks and low-tide elevations, and affirmed that claimants’ maritime entitlements in the SCS must derive from the 1982 United Nations Convention on the Law of the Sea (UNCLOS), not vague historical assertions.

Yet the decade since has exposed the limits of international adjudication when a powerful state refuses to accept an adverse ruling. China rejected the Award as “null and void” and expanded its coast guard, maritime militia and naval presence across contested waters. Dangerous confrontations involving Chinese vessels and Philippine military, coast guard and civilian vessels have become routine, particularly around Second Thomas Shoal and Scarborough Shoal. Water-cannon incidents, collisions and aggressive manoeuvres have become increasingly familiar features of maritime encounters between Chinese and Philippine vessels.

If assessed solely through the lens of compliance, the Award may appear disappointing. Like most international judgments, it lacked any compulsory enforcement mechanism and ultimately depended on state acceptance and political pressure. China rejected the ruling, retained physical control over certain occupied features and continued to expand its maritime presence in contested waters. ASEAN has neither formally recognised the Award nor incorporated it in the Code of Conduct (CoC) drafting process nor even formally recognised it. To some observers, this seemed to expose the limits of international law.

That conclusion, however, misapprehends how international judgments often work. Their significance rarely lies in immediate compliance. Rather, they shape legal narratives, constrain future claims, influence diplomacy and gradually alter the boundaries of legitimacy. In this respect, the 2016 Award has been profoundly consequential.

What it achieved was more foundational: it established a legal baseline against which future state behaviour and conduct will be judged.

The ruling fundamentally changed the legal and diplomatic terrain of the dispute. Before 2016, the SCS was often framed as a contest of overlapping historical claims. After the Award, the debate increasingly became one about the defence of the rules-based maritime order. The tribunal had decisively clarified that maritime rights in the SCS must be grounded in UNCLOS, not ambiguous historical entitlements.

This matters because international law shapes not only judicial outcomes but also the normative boundaries within which nation-states justify and defend their conduct. Even China, despite rejecting the Award, increasingly frames its maritime positions through legal concepts recognised under UNCLOS, invoking territorial seas, exclusive economic zones, continental shelves and sovereign rights rather than relying solely on broad assertions of historic entitlement. That Beijing continues to contest the Award while arguing largely within the UNCLOS framework underscores a broader point: legal legitimacy still matters. States do not expend significant effort constructing legal arguments unless legal legitimacy continues to carry political and diplomatic value.

The Award has quietly reshaped regional diplomacy. The Philippines, despite policy fluctuations under different administrations, has progressively embedded the ruling into its maritime law and diplomatic posture. Vietnam and Malaysia have advanced maritime claims and continental shelf submissions broadly consistent with the 2016 tribunal’s reasoning.

Beyond Southeast Asia, the Award has become a touchstone for a broader coalition defending freedom of navigation and UNCLOS’ integrity. Australia, Japan, the United States, the United Kingdom, France, Germany and Canada have expressed support for the ruling and for a rules-based maritime order. The Award now underpins much of the international diplomatic response to excessive maritime claims in the Indo-Pacific.

Yet the 10th anniversary of the ruling arrives at a dangerous moment.

The SCS today is more militarised, crowded and geopolitically entangled than it was in 2016. Strategic rivalry between China and the US has intensified sharply. China increasingly views the SCS not merely as the subject of a territorial dispute but as part of a wider strategic contest over regional hegemony and American containment. The US, meanwhile, increasingly regards stability in the SCS as central to maintaining a free and open Indo-Pacific and preserving a rules-based regional order. The danger lies in recurring confrontations between China and other claimant states and in the growing risk that local maritime incidents may become entangled in wider great-power rivalry.

ASEAN remains divided and institutionally constrained. Negotiations for a CoC continue, but after years of talks, doubts persist over whether any agreement will be genuinely binding or meaningful. The Philippines’ chairing ASEAN this year places Manila in a particularly delicate position: balancing regional diplomacy while resisting efforts, whether from China or through the dynamics of consensus-based regional diplomacy, to dilute the Award’s legal significance.

The central lesson of the past decade is sobering – international law alone cannot resolve geopolitical conflicts, but neither can power erase law.

The Award did not “resolve” the SCS disputes; no tribunal could. What it achieved was more foundational: it established a legal baseline against which future state behaviour and conduct will be judged. It narrowed the range of legally defensible claims. It preserved the authority of UNCLOS in one of the world’s most strategically vital maritime spaces. Most importantly, it ensured that the contest in the SCS would not be fought solely through coercion and military power, but also through law, legitimacy and international opinion.

That may prove to be the ruling’s enduring significance, especially if other Southeast Asian states could eventually weave the principles of the Arbitration Award into their maritime and foreign policies. Still under negotiation, the CoC’s legitimacy will also depend on how it approximates the Award’s underlying principles.

The true value of the Award lies not in its immediate enforcement, but in preventing excessive maritime claims and coercive practices from being accepted as lawful or normal through repetition and acquiescence. Even amid coercion, grey-zone tactics and intensifying strategic rivalry, ASEAN member states must continue to invoke UNCLOS and the rules-based order as the governing framework for all states’ maritime conduct.

10 years on, the South China Sea remains a contest between law and power. The 2016 Arbitration Award ensured that law remains firmly in the fight.

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