Dr. Aurel Sari on “Choppy Waters: Is China in Breach of the United Nations Charter?

I am very pleased to welcome back Lawfire^® contributor and LENS Conference participant, Dr. Aurel Sari.  Dr. Sari is a very highly-respected international law expert, and one of the world’s top authorities on the legal aspects of “grey zone” war. 

Today Aurel expertly analyzes for us the legal dimensions of the troubling–and dangerous–maritime incidents occurring between China and the Philippines.

Choppy Waters: Is China in Breach of the United Nations Charter?

Aurel Sari

­­­­These days, barely a week goes by without a maritime incident in the South China Sea. Just over a fortnight ago, a China Coast Guard vessel intentionally rammed a Philippine Coast Guard ship, punching a three-and-a-half foot hole into its hull.

Over the last two years, the number and intensity of clashes between the People’s Republic of China (PRC) and the Philippines has increased steadily. Beijing describes its actions as law enforcement measures, designed to uphold its territorial and maritime rights.

In reality, at least some of China’s maritime operations qualify as a use of force within the meaning of the United Nations Charter, as I have argued in a recent paper published in International Law Studies.

The South China Sea

Why does this matter? The South China Sea is one of the busiest maritime trade routes in the world. Since the end of the Second World War, it has been the subject of overlapping maritime and territorial disputes between coastal States. The PRC asserts the most expansive claims, seeking to exert control over approximately ninety per cent of the South China Sea.

In advancing its interests, the PRC has adopted an integrated ‘power and law’ approach. Beijing has greatly expanded its presence in disputed waters, regularly deploying military, coast guard and paramilitary assets to demonstrate its capabilities and assert Chinese claims.

Legal warfare

As part of its broader ‘legal warfare’ efforts, China has advanced arguments based on customary international law to claim historic rights over vast swathes of water and numerous maritime features. When these claims were rejected in 2016 in the South China Sea arbitration initiated by the Philippines, the PRC declared the arbitral award to be ‘null and void’.

These different lines of effort are not isolated, but form part of an integrated, multielement strategy where the PRC invokes legal entitlements to justify its naval operations and in turn employs its naval assets to aggressively assert and enforce those legal entitlements it lays claim to in the South China Sea.

Incidents at the Second Thomas Shoal

The Second Thomas Shoal, a reef forming part of the Spratly Islands, is one of the major flashpoints between China and the Philippines. The reef falls within the Exclusive Economic Zone (EEZ) of the Philippines, but the PRC asserts sovereignty over it as part of its broader sovereignty claim over the Spratly Islands.           

In 1999, the Philippines intentionally ran aground the BRP Sierra Madre, a transport vessel originally built for the United States Navy, to create an outpost sustaining a small military presence at the reef. China has repeatedly protested against the grounding.

From 2013 onwards, Beijing has adopted a more assertive approach which includes disrupting the regular resupply missions carried out by the Philippine Navy to sustain and rotate the marines on board the BRP Sierra Madre.           

Most incidents at the Second Thomas Shoal have not resulted in material damage. For example, in June 2023, China Coast Guard vessels followed, harassed and blocked two Philippine Coast Guard ships to discourage them from approaching the Shoal. Such aggressive manoeuvres take place on a fairly regular basis.

On other occasions, Philippine vessels and crews have sustained damage or injury. For example, in March 2024, China Coast Guard vessels employed their water cannons against the Unaizah May 4, a Philippine Navy-operated, civilian chartered resupply boat, shattering its windshield and injuring four Philippine Navy sailors on board.

In June 2024, Chinese ships deliberately rammed Philippine vessels, with Chinese uniformed personnel using knives and other pointed weapons to puncture the hull of the inflatable boats employed by the Philippine Navy.

For the first time, Chinese personnel boarded a Philippine vessel, threatened its crew, seized equipment, including small arms, and caused significant damage. Eight Philippine sailor were reported to have suffered injuries, including one who was seriously injured.

A use of force?

The PRC consistently justifies its actions as measures of maritime law enforcement designed to protect its sovereign rights. However, a closer look reveals that at least some of China’s operations qualify as a ‘use of force’ within the meaning of Article 2(4) of the United Nations Charter.           

First, the prohibition to use force applies ‘regardless of the weapons employed’ (Nuclear Weapons Advisory Opinion, para. 39). As the damage inflicted on the Unaizah May 4 in March 2024 has shown, ramming and the use of high-output water cannons involves physical violence capable of causing substantial material harm. As such, it can be equated to the use of conventional weapons.

Second, while the majority of confrontations at the Second Thomas Shoal have not caused material harm of any significance, some clashes have inflicted heavy damage on Philippine vessels and also caused serious injury to their personnel. Even though the level of material harm involved in these incidents was not of the utmost gravity, it is of sufficient intensity to qualify as a use of force, even when measured against a de minimis threshold.

Third, Beijing has relied heavily on China Coast Guard units to disrupt Philippine operations in and around the Second Thomas Shoal. In doing so, they have worked in concert with Chinese navy assets. There is no doubt that these units have acted in an official capacity and that their activities must be attributed to the PRC.

Fourth, China has interfered with vessels owned or operated by the Philippines that benefit from sovereign immunity. The principle of sovereign immunity exempts these vessels not only from judicial process, but also from enforcement action, including boarding and arrest. Accordingly, there is no legal basis for subjecting vessels enjoying sovereign immunity to law enforcement action when on the high seas.

Fifth, Chinese operations at the Second Thomas Shoal are part of China’s ongoing dispute with the Philippines over territorial and maritime rights in the South China Sea. As such, Chinese operations are not concerned with traditional maritime law enforcement tasks, such as boarding, inspecting or arresting other vessels, but appear to be aimed at interdiction and deterrence.         

The preceding point is reinforced by China’s warning that it will continue ‘to adopt resolute measures to safeguard its territorial sovereignty and maritime rights and interests’ and that the Philippines ‘should be prepared to bear all potential consequences’ were it to continue on the path of ‘infringement and provocation’.

The tribunal in the Guyana v. Suriname arbitration found similar words to constitute a threat to use force within the meaning of the Charter (Award, paras 439 and 445).

All of these factors point in the same direction: at least some of the actions undertaken by Chinese vessels at the Second Thomas Shoal do not qualify as measures of maritime law enforcement, but amount to the use of force within the meaning of Article 2(4) of the United Nations Charter.

Strategic implications

Calling out aggressive Chinese manoeuvres as breaches of Article 2(4) of the United Nations Charter might offer several benefits to the Philippines.

First, it would challenge China’s false legal narrative of law enforcement and reveal its actions for what they are. The main thrust of China’s legal strategy in the South China Sea is to construct a parallel legal reality based on alternative facts and the misapplication of the law to them.

In this world of legal fantasy, the PRC enjoys indisputable territorial sovereignty over the Second Thomas Shoal and carries out law enforcement measures to resolutely protect its sovereign rights against repeated provocations by the Philippines.

All of this is calibrated not only to clothe Chinese operations in a mantle of legality, but to enable China to carry out low-level coercive actions in the hope of circumventing the thresholds imposed by the United Nations Charter.

Second, it would entail specific legal consequences. In so far as the use of force by China amounts to an internationally wrongful act, it must cease and not be repeated. The Philippines would be entitled, amongst other things, to demand reparation and to take commensurate countermeasures against China.

The Philippines could also consider bringing the matter to the attention of the Security Council or of the General Assembly pursuant to Article 35 of the United Nations Charter as a dispute or situation ‘the continuance of which is likely to endanger the maintenance of international peace and security’.

Third, the fact that China used force within the meaning of the Charter raises the question whether this engages the Philippines’ right of self-defence. Not every use of force in contravention of Article 2(4) gives rise to the right to respond in a forcible manner. The right to employ counterforce is available only in response to the most grave uses of force, namely those that rise to the level of an ‘armed attack’.

The U.S. view on use of force

However, the gap between low-intensity uses of force which do not reach that threshold and more serious ones which do is not exceedingly wide. In this context, it should be recalled that ‘the United States has for a long time taken the position that the inherent right of self-defence potentially applies against any illegal use of force.’

In other words, the United States denies that there is any gravity threshold to be crossed before a use of force qualifies as an armed attack and engages the right of individual and collective self-defence.

Although this is an isolated position, it colours the United States’ understanding of its mutual defence agreement with the Philippines, potentially bringing its mutual defence guarantee into play far earlier than would otherwise be the case. Invoking Article 2(4) of the Charter thus has escalatory potential and this in turn may have a deterrent effect on China.

However, it cannot be taken for granted that China would in fact be deterred. Should the Philippines and third States invoke the language of Article 2(4) of the Charter, China will almost certainly consider this to be a direct challenge to its strategic interests in the South China Sea and treat it as such.

Concluding thoughts

Beijing has repeatedly underlined the strategic significance it attaches to the South China Sea and signalled its willingness to assert its interests in the region: it has invested too much into its narrative and capabilities to not respond to an intensification of the dispute in the South China Sea in an aggressive manner by raising the stakes even higher.

Uttering the magic words of Article 2(4) of the Charter is not going compel China, without more, to change course, but most likely prompt it to fight back.

All of this suggests that the Philippines and third States should invoke Article 2(4) of the Charter only if they are prepared to back up their words with other measures capable of deterring China from escalating. Absent the capacity and political will to take such measures, relying on the language of the Charter will not secure desired outcomes and potentially may be counterproductive.

About the Author

Dr. Aurel Sari is a Professor of Public International Law at the University of Exeter and a Fellow of Supreme Headquarters Allied Powers Europe. Dr Sari studied law and politics at the University of Durham (BA, First Class), the London School of Economics (LLM, Distinction) and University College London (PhD). His scholarship focuses primarily on international conflict and security law and the law relating to military operations.

Dr Sari is one of the principal experts on the legal aspects of hybrid warfare. He has published widely in leading academic journals on the law of armed conflict, status of forces agreements, peace support operations, international human rights law and the legal framework of European security and defence policy. His recent publications include Hybrid Threats and Grey Zone Conflict: The Challenge to Liberal Democracies, co-edited with Professor Mitt Regan and published by Oxford University Press.

The views expressed by guest authors do not necessarily reflect my views or those of the Center on Law, Ethics and National Security, or Duke University (see also here).

Remember what we like to say on Lawfire^®: gather the facts, examine the law, evaluate the arguments – and then decide for yourself!