The Scarborough Shoal, called Bajo de Masinloc in the Philippines and Huangyan Island in China, has once again become the center of an escalating maritime dispute. The Philippines answered China’s September 10, 2025 declaration of a “national nature reserve” with a strong, unequivocal diplomatic protest, insisting the plan is an “illegitimate and unlawful” infringement on its sovereignty and a “pretext toward eventual occupation.” The United States quickly echoed this stance, with Secretary of State Marco Rubio affirming that Washington stands with Manila and warning that China’s move is “yet another coercive attempt to advance sweeping territorial and maritime claims.” This unified response highlights how China’s latest action fits a familiar pattern of defiance, from rejecting the 2016 Permanent Court of Arbitration ruling to deploying maritime militia and engaging in dangerous “gray zone” confrontations, including an August 2025 collision near the shoal. It also exposes environmental hypocrisy, as Chinese activities have already destroyed thousands of acres of coral reef across the South China Sea.
In this standoff, allied unity has become the defining counterweight to unilateral power projection. The Philippines and its partners stress that the conflict is not only about one reef but about safeguarding freedom of navigation, regional stability, and the integrity of international law in waters through which more than $3.36 trillion in global trade passes each year. With China showing no sign of retreat and Washington reaffirming that its 1951 Mutual Defense Treaty with Manila covers armed attacks in the South China Sea, the Scarborough Shoal dispute now stands as a high-stakes test of whether a rules-based maritime order can endure in the face of coercion.
The Philippines’ Formal Objection
The Philippine government mounted an immediate, forceful, and carefully documented response to China’s September 10, 2025 announcement of a so-called “Huangyan Island National Nature Reserve” at Scarborough Shoal. On September 12, just two days after Beijing’s proclamation, the Department of Foreign Affairs (DFA) lodged what it described as a “strong, unequivocal and formal” diplomatic protest. The speed and clarity of the démarche signaled Manila’s view that China’s environmental rationale is merely a legal fiction and that the move constitutes a direct assault on Philippine sovereignty and the rules-based maritime order.
The protest laid out a three-tier legal and political case. First, it reaffirmed that Scarborough Shoal, known locally as Bajo de Masinloc, lies only about 124 nautical miles from Luzon and well inside the Philippines’ 200-nautical-mile Exclusive Economic Zone (EEZ) and continental shelf. Under the United Nations Convention on the Law of the Sea (UNCLOS), which both countries have ratified, only the coastal state may establish marine protected areas, fisheries management zones, or nature reserves within its EEZ. The DFA therefore branded any Chinese declaration of a protected area there as “illegitimate and unlawful,” in violation of both international and Philippine domestic law, and warned that Manila retains exclusive sovereign rights to fisheries, energy resources, and environmental management in the area.
Second, the protest argued that China’s purported ecological objective is a façade for territorial expansion. National Security Adviser Eduardo Año condemned the plan as “patently illegal” and “a pretext toward eventual occupation,” invoking Beijing’s long-established pattern of using soft-sounding initiatives to secure hard strategic gains. He drew pointed comparisons to the 1995 Mischief Reef episode, when China initially claimed to be building a simple “fishermen’s shelter” but later transformed the reef into a fortified artificial island bristling with radar, missiles, and runways. By couching a sovereignty grab in the language of conservation and biodiversity, Manila stressed, Beijing is waging lawfare, leveraging legal-sounding acts to create faits accomplis at sea and shift the status quo without firing a shot.
Third, the Philippines categorically rejected the legitimacy of any Chinese claim to the shoal, anchoring its position in the 2016 Permanent Court of Arbitration (PCA) award in The Hague. That tribunal invalidated China’s sweeping nine-dash (now ten-dash) line and confirmed the Philippines’ sovereign rights to fisheries and seabed resources at Scarborough and elsewhere in its EEZ. The DFA’s note verbale demanded that Beijing “immediately withdraw its State Council issuance,cease any administrative or enforcement actions at the shoal, and comply with the legally binding PCA ruling, a ruling that China has repeatedly dismissed but that remains authoritative under international law.
By filing this detailed protest within forty-eight hours, Manila demonstrated a multi-layered strategy: assert and defend its rights under UNCLOS, expose Beijing’s use of environmental pretexts as a geopolitical tool, and mobilize global opinion to isolate China diplomatically. The prompt and meticulously argued objection highlights the Philippines’ determination to meet lawfare with law-based diplomacy, signaling to both Beijing and the wider international community that it will contest every attempt to erode its maritime sovereignty and will not allow environmental rhetoric to camouflage strategic encroachment.
The United States’ Unwavering Support
The United States reacted swiftly and decisively to China’s September 10, 2025 announcement of a so-called “Huangyan Island National Nature Reserve” at Scarborough Shoal, aligning itself firmly with Manila’s position. On September 12, 2025, U.S. Secretary of State Marco Rubio issued a forceful public statement that left no ambiguity about Washington’s stance. “The U.S. stands with our Philippine ally in rejecting China’s destabilizing plans to establish a ‘national nature reserve’ at Scarborough Reef,” Rubio declared. In framing the move as “destabilizing,” the U.S. signaled that it views the action not as a routine environmental initiative but as a deliberate challenge to the regional status quo and to the international law of the sea.
Rubio sharpened the point by describing Beijing’s action as “yet another coercive attempt to advance sweeping territorial and maritime claims in the South China Sea at the expense of its neighbors and regional stability.” His words highlighted a U.S. assessment that China’s environmental justification masks a broader strategy of salami-slicing, incremental, coercive steps aimed at changing facts on the ground without triggering open conflict. The statement placed the Scarborough Shoal move in the context of China’s longer pattern of building and militarizing artificial islands, and of using maritime militia and coast guard vessels to intimidate rival claimants.
Beyond political messaging, Washington anchored its response in international law. The U.S. State Department explicitly invoked the 2016 Permanent Court of Arbitration ruling, which invalidated China’s “nine-dash line” claim and concluded that Beijing had unlawfully interfered with traditional Filipino fishing activities at Scarborough Shoal. By emphasizing that the arbitral decision is “final and legally binding,” the U.S. reinforced Manila’s legal standing and delegitimized China’s new claim of environmental jurisdiction. This legal framing is crucial because it signals that the United States does not see the issue as a matter of bilateral dispute but as a violation of a global rules-based maritime order.
Equally significant was the security dimension of the American response. U.S. officials reiterated that the 1951 Mutual Defense Treaty (MDT), the cornerstone of the U.S.–Philippine alliance, applies to armed attacks on Philippine armed forces, public vessels, or aircraft in the South China Sea, including at Scarborough Shoal. This explicit linkage sends a clear deterrent message: any Chinese use of force to enforce its “nature reserve” would not only meet diplomatic opposition but could trigger collective defense obligations.
By combining strong political language, firm legal backing, and an unmistakable security guarantee, Washington’s reaction went far beyond routine expressions of concern. It demonstrated a full-spectrum commitment to Manila, diplomatic, legal, and military. The speed and clarity of this support also highlight the strategic importance the United States attaches to Scarborough Shoal as a test case for freedom of navigation and the integrity of international maritime law. In doing so, Washington transformed what Beijing might have hoped would be a local administrative action into a global flashpoint and a defining moment for the U.S.–Philippine alliance.
Northern Luzon Marines Ready to DEFEND Philippines Watch Their Power
Context of China’s Coercive Actions and Legal Defiance
China’s declaration of a “national nature reserve” at Scarborough Shoal is not an isolated act, but the latest move in a long-running pattern of legal defiance and coercive tactics in the South China Sea. A key backdrop to the current crisis is the 2016 Permanent Court of Arbitration (PCA) ruling in The Hague, which delivered a sweeping victory for the Philippines. The tribunal rejected China’s expansive “nine-dash line” and its assertions of “historic rights” to resources across nearly the entire South China Sea. It found that Beijing had violated Manila’s sovereign rights by blocking Filipino fishermen and interfering with petroleum exploration within the Philippine Exclusive Economic Zone (EEZ). Yet China, which refused to participate in the proceedings, dismissed the decision outright as a “sham,” and has continued to defy it for nearly a decade, undermining the authority of international maritime law.
This defiance has been reinforced by a persistent “gray zone” strategy, coercive operations that stop short of open warfare but steadily erode the Philippines’ position. Chinese coast guard and maritime militia vessels routinely block Filipino fishing boats, shadow patrols, and create a near-constant atmosphere of intimidation around Scarborough Shoal and other contested areas. Tensions escalated further in August 2025, when a Chinese naval ship and a Chinese coast guard vessel collided while jointly attempting to intercept a Philippine coast guard boat near the shoal. Such incidents illustrate how China blurs the line between law enforcement and military action, making it difficult for opponents to respond without risking escalation.
Adding to the controversy is China’s environmental hypocrisy. While presenting the Scarborough Shoal “nature reserve” as an act of ecological stewardship, Beijing’s own activities have caused massive ecological damage across the South China Sea. A 2023 report by the Centre for Strategic and International Studies (CSIS) documented that China’s large-scale land reclamation and island-building projects had buried over 4,600 acres of coral reef, while the harvesting of giant clams by Chinese fishermen had damaged another 16,353 acres. These practices have devastated marine biodiversity and fisheries that sustain thousands of Southeast Asian livelihoods.
Taken together, these factors reveal the deeper context of China’s latest claim. By rejecting a binding international ruling, employing dangerous gray zone tactics, and cloaking environmentally destructive behavior in the language of conservation, Beijing continues to test the limits of global law and patience. The Scarborough Shoal “nature reserve” is thus not a benign environmental measure, but a continuation of a calculated campaign to expand control and reshape the maritime order in its favor.
China to Turn Scarborough Shoal Into ‘Nature Reserve’? Philippines on Edge
Conclusion: Upholding a Rules-Based Order
The Scarborough Shoal standoff highlights a fundamental test of the modern maritime order: whether powerful states can rewrite international law through coercion, or whether collective action can preserve established norms. By standing shoulder to shoulder, the Philippines and the United States, joined by partners like Australia, Canada, and Japan are demonstrating allied unity in defense of international law. Their coordinated diplomatic protests, security assurances, and naval presence send a clear message that unilateral claims have no place in shared waters.
This confrontation is about far more than a single reef. At stake are freedom of navigation, the stability of the Indo-Pacific, and the credibility of the global legal framework. The South China Sea is one of the world’s busiest trade arteries, with over $3.36 trillion in commerce flowing through it each year. Ensuring that these sea lanes remain open and governed by law is vital to global economic health and regional security alike.
Looking ahead, the dispute is likely to remain a persistent flashpoint. China shows no sign of backing away from its sweeping claims, while the United States and its allies are equally firm in defending a rules-based order. Continued diplomatic coordination, legal reinforcement, and carefully calibrated security cooperation will be critical to prevent escalation and to uphold the principle that might not make right in international waters.
