Divergence and Tacit Understanding in the China–Philippines Provisional Arrangement at Second Thomas Shoal

Second Thomas Shoal has become one of the most sensitive flashpoints in the South China Sea dispute between China and the Philippines. Since 1999, when the Philippines deliberately grounded the warship BRP Sierra Madre on the shoal, the feature has steadily evolved into a key front line in the broader maritime contest between the two sides. After the sharp confrontation on June 17, 2024, the situation came close to spinning out of control. In July 2024, however, Beijing and Manila reached a provisional arrangement through diplomatic channels regarding resupply operations at the shoal, which the Philippine side described as a "Provisional Understanding." From the conclusion of that arrangement through March 4, 2026, the Philippines carried out 13 rotation and resupply missions-roughly once every six weeks. Philippine officials say these missions have since proceeded without dangerous encounters between the two sides. By that measure, the arrangement has worked: the situation at Second Thomas Shoal has shifted from intense confrontation to a condition of relative manageability.

This provisional arrangement is more than a tactical deconfliction mechanism. It also reflects a limited but meaningful tacit understanding between China and the Philippines on crisis management in the South China Sea.

The core divide: fundamental opposition between sovereignty narratives and legal interpretation

The fundamental disagreement between China and the Philippines over Second Thomas Shoal centers on their competing claims of sovereignty and legality.

China has consistently maintained its sovereignty over the Spratly Islands, including Second Thomas Shoal. From Beijing's perspective, the Philippines' grounding of a warship there constitutes an infringement on Chinese sovereignty and violates the 2002 Declaration on the Conduct of Parties in the South China Sea (DOC), especially the commitment to "refraining from action of inhabiting on the presently uninhabited islands, reefs, shoals, cays, and other features". China's long-term objective remains clear: the removal of the grounded vessel BRP Sierra Madre and the restoration of the shoal to a condition without personnel or facilities.

The Philippines, by contrast, insists on its claim to parts of the Spratly Islands under what it calls the Kalayaan Island Group. It views the BRP Sierra Madre as a symbolic outpost that preserves its presence at Second Thomas Shoal. Through continued resupply and maintenance, Manila seeks to ensure the ship's long-term viability as a forward position.

Although the United States, as the Philippines' important ally, is not a direct party to the dispute over Second Thomas Shoal, it has made its policy preferences unmistakable. Washington has repeatedly stated that the U.S.-Philippines Mutual Defense Treaty applies to the South China Sea and has characterized Chinese actions around the shoal as coercive. In practical terms, the United States supports maintaining the status quo in which the BRP Sierra Madre remains grounded, and the Philippines can sustain rotation and resupply missions. Preventing China from forcing the removal of the Philippine vessel is therefore part of Washington's near-term objective.

For China, the issue is fundamentally about sovereignty. For the Philippines, it is fundamentally about preserving a de facto occupation on the ground-or, more precisely, on the shoal. That gap is so wide that genuine consensus remains out of reach.

Limited understanding: crisis management to avoid escalation

Yet the very existence of the provisional resupply arrangement suggests that the parties do share a limited tacit understanding on preventing escalation. In effect, the arrangement has produced a fragile modus vivendi centered on one principle: freezing the status quo.

First, both sides recognize the potentially grave consequences of escalation at Second Thomas Shoal. The June 2024 confrontation demonstrated how quickly close-range encounters between maritime forces can generate miscalculation, physical injury, or even a broader crisis. It also underscored the risk that the United States, under its alliance commitments to the Philippines, could become more directly involved, turning a localized maritime standoff into a larger regional security emergency.

Second, the provisional arrangement established a minimal operational framework. China's official position has been that, while it is assumed that the Philippines will ultimately remove the grounded vessel, Beijing may permit the delivery of basic living supplies in the meantime. For Beijing, this arrangement amounts to a short-term acceptance of the BRP Sierra Madre's continued presence, while preserving what it sees as effective monitoring and control.

The Philippines, for its part, has framed the tacit understanding primarily as a mechanism to ensure the basic needs of the troops stationed aboard the vessel and to avoid confrontation. Since July 2024, it has completed multiple rotation and resupply missions without a repeat of earlier dangerous clashes. For Manila, the arrangement secures the survival and rotation of the troops on board, allowing it to maintain its symbolic foothold at Second Thomas Shoal.

From Washington's perspective, as long as the Philippines can continue resupply operations and China and the Philippines avoid direct confrontation, there is no immediate trigger for U.S. intervention. As a result, even while publicly backing Manila, the United States has tacitly accepted this limited management mechanism between the two parties.

This is why, despite their public insistence on incompatible legal and political positions, the parties have in practice arrived at a limited tacit understanding-one that might be described as separate interpretations, shared implementation.

A fragile equilibrium: risks embedded in the arrangement

Still, this tacit understanding is inherently unstable.

To begin with, Beijing and Manila do not interpret the arrangement in the same way. China stresses that Philippine resupply operations must be reported in advance and subjected to on-site inspection. The Philippines has not acknowledged any obligation to comply with such conditions.

Second, there is ongoing disagreement over which supplies are permissible. China says only basic living necessities are allowed and firmly opposes the transport of large quantities of construction materials. But the BRP Sierra Madre has suffered decades of structural deterioration due to corrosion and seawater exposure, making reinforcement an urgent concern for the Philippines. In practice, Manila has a continuing need to bring in structural reinforcement materials to extend the vessel's life.

Third, the two sides have fundamentally different views of the arrangement's end state. China sees it as a transitional measure whose ultimate purpose is to remove the grounded vessel. The Philippines sees it as a practical mechanism for preserving the vessel's presence and, eventually, establishing a permanent garrison.

If either side pushes beyond these still-ambiguous boundaries-for example, if the Philippines transports construction materials to reinforce the vessel and expand its military presence, or if China intensifies maritime controls through more forceful measures-the situation could quickly become tense again.

Conclusion

The provisional resupply arrangement at Second Thomas Shoal illustrates a recurring reality in the South China Sea: when sovereignty disputes cannot be resolved, the parties often resort to temporary mechanisms to manage risk. In that sense, the arrangement reflects both the depth of Sino-Philippine disagreement and their shared desire to prevent escalation.

For the foreseeable future, as long as all sides continue to prioritize crisis avoidance, this uneasy tacit understanding amid unresolved differences may endure. But its durability depends entirely on whether the parties continue to observe the current behavioral boundaries. If those boundaries are broken, Second Thomas Shoal could once again become one of the most dangerous flashpoints in the South China Sea.