PH-F-06: The West Philippine Sea Confrontation and the "Assertive Transparency" Doctrine (2023–2026)

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1. Key Takeaways

  • Between 2023 and 2026 the Philippines reversed the central operational logic of the Duterte-era West Philippine Sea posture — from "quiet diplomacy" to "assertive transparency" — making the publicising of Chinese coercion the principal Philippine instrument of the contest. Where Duterte (2016–2022) had treated maritime incidents as matters to be managed discreetly to preserve the China relationship, the Marcos Jr. administration treated them as evidence to be documented, attributed by hull number, and broadcast within hours. The strategy, associated with PCG Commodore Jay Tarriela's communications direction, embedded local and international journalists aboard resupply and patrol missions and released video of water-cannon, ramming, blocking, laser, and boarding incidents in near-real time. Transparency became simultaneously a deterrent (imposing reputational cost), an evidentiary instrument (supplying allies material for joint statements), and a domestic legitimation device (building the public consent within which the policy could be sustained).

  • The 2016 Permanent Court of Arbitration award (PCA Case No. 2013-19) functions as the legal spine of the entire confrontation, and the Marcos administration's reactivation of it is the single most consequential continuity decision of the period. The 12 July 2016 award found that China's nine-dash-line historic-rights claim has no legal basis, that no Spratly feature generates an exclusive economic zone, that Second Thomas Shoal and Mischief Reef lie within the Philippine EEZ, and that Scarborough Shoal generates only a territorial sea. Duterte set the award aside diplomatically without repudiating it; Marcos Jr. moved it from dormant talking point to operational doctrine — invoked in diplomatic protests, in PCG attributions, in multilateral statements, and ultimately codified into Philippine domestic law in November 2024. China's position throughout has been that it did not participate in the arbitration, does not recognise the award, and treats it as "null and void."

  • Second Thomas Shoal — Ayungin Shoal to Filipinos, Ren'ai Jiao to China — is the defining flashpoint of the period, organised around the resupply of the grounded BRP Sierra Madre. The decommissioned tank-landing ship, deliberately run aground on the shoal in 1999 and manned continuously by a small Philippine Marine detachment, is both a sovereignty marker and a vulnerability: its decaying hull must be resupplied by sea, and each Rotation and Reprovision (RORE) mission runs a gauntlet of China Coast Guard and maritime-militia interception. From 2023 the CCG escalated from blocking and water-cannon to, on 17 June 2024, a boarding in which CCG personnel wielding bladed implements punctured Philippine boats, seized weapons and equipment, and a Filipino sailor lost a thumb — the most violent encounter since the 2012 Scarborough standoff and the closest the alliance has come to a Mutual Defense Treaty test.

  • The 17 June 2024 incident produced a sharp escalation followed by a deliberate, jointly managed de-escalation — and that sequence is the central case study in Philippine and US escalation management. Manila and Washington, after consultation, publicly characterised the incident as falling short of an "armed attack" under the MDT — a calibrated judgement that condemned the conduct, reserved the treaty instrument, and avoided an automatic escalation spiral. Within weeks, intensive bilateral diplomacy with Beijing produced the 21 July 2024 "provisional arrangement" permitting resupply under disputed terms. The episode demonstrated both the value and the limit of the transparency doctrine: publicity mobilised an unprecedented chorus of allied condemnation, but it could not by itself stop the coercion, which abated only when a quiet diplomatic channel produced a tacit accommodation.

  • The July 2024 provisional arrangement is the most important — and most ambiguous — diplomatic instrument of the confrontation, deliberately left undefined by both sides. Manila insists the arrangement permits resupply "without prejudice" to sovereignty and entails neither prior notification to nor inspection by Chinese authorities; Beijing insists it requires Philippine prior notification and limits cargo to humanitarian supplies, excluding construction materials that could reinforce the hulk. Neither side published an agreed text. The constructive ambiguity has held the resupply tempo at a lower intensity since mid-2024 while leaving the underlying sovereignty question wholly unresolved. The arrangement is best read not as a settlement but as a managed pause whose durability depends on neither party forcing the other to clarify what was deliberately left vague.

  • Scarborough Shoal (Bajo de Masinloc / Panatag / Huangyan Dao) is the period's slow-burn flashpoint, where China consolidated control through floating barriers and, in November 2024, a formal straight-baseline declaration that escalated the contest into lawfare. Under de facto Chinese control since the 2012 standoff, Scarborough saw recurrent buffer-zone installations across the lagoon mouth — which the PCG twice publicly cut — and harassment of Filipino fishermen. Four days after the Philippines codified its maritime zones in domestic law, China announced "baselines of the territorial sea adjacent to Huangyan Dao," asserting straight baselines around a feature the 2016 award had found generates only a territorial sea. The exchange established that the contest now runs through duelling domestic legal instruments as much as through ships at sea.

  • Sabina Shoal (Escoda / Xianbin Jiao) was the period's second major standoff, and its outcome exposed the operational ceiling of the transparency strategy. From April 2024 the PCG forward-deployed the flagship BRP Teresa Magbanua to Sabina to deter suspected Chinese reclamation, sustaining a months-long presence under blockade, water-cannon, and a 19 August 2024 collision. The vessel withdrew in mid-September 2024 citing supply and crew constraints — a withdrawal Manila called routine and Beijing called a victory. Sabina demonstrated that publicity and legal right cannot substitute for logistical endurance: sustained presence operations require a depth the PCG, despite Japan-built acquisitions, does not yet possess at scale.

  • The contest is conducted overwhelmingly through "gray-zone" instruments — the China Coast Guard and the People's Armed Forces Maritime Militia (PAFMM) rather than the PLA Navy — by deliberate Chinese design to stay below the threshold of armed conflict and complicate legal characterisation. The CCG, reorganised under the Central Military Commission since 2018 and armed with water cannon, ramming hulls, and (from June 2024) domestic "law-enforcement" regulations authorising detention of foreigners in claimed waters, performs coercion in the idiom of policing. The militia — nominally civilian fishing vessels integrated into PLA command — masses by the dozens to hundreds at features such as Whitsun and Iroquois. This architecture lets Beijing assert control while denying that any military force is involved, the core analytical puzzle the Philippine documentation campaign was built to penetrate.

  • The Marcos administration institutionalised the doctrine through the National Maritime Council (2024), succeeding the National Task Force for the West Philippine Sea, centralising a whole-of-government response. [TBD-VERIFY: the National Maritime Council was established by Executive Order in March 2024 — confirm EO number/date.] The NMC drew together the DFA, the Department of National Defense, the AFP, the PCG, the National Security Council, and the maritime-domain-awareness apparatus, replacing the looser NTF-WPS coordination. Institutionalisation signalled that assertive transparency was not a personality-driven communications tactic but a settled instrument of state, with a standing bureaucratic home, a unified messaging line, and a mechanism to coordinate the legal, diplomatic, operational, and informational dimensions of the contest.

  • The November 2024 Maritime Zones Act and Archipelagic Sea Lanes Act translated the 2016 award into binding Philippine domestic statute, and China's immediate rejection confirmed that the legal contest is now bilateral, active, and ongoing. Republic Act 12064 codified the Philippine territorial sea, contiguous zone, EEZ, and continental shelf in conformity with UNCLOS and the award, with criminal penalties for violations; RA 12065 designated archipelagic sea lanes under UNCLOS Article 53. Beijing declared both "null and void" and answered with the Scarborough baseline declaration. The lawfare exchange matters because it makes the Philippine claim permanent legal patrimony — harder for any future administration to quietly abandon — while demonstrating that legislation alone changes nothing on the water.

  • Internationalisation is the strategy's force-multiplier: each incident is converted into a coordinated chorus of allied statements, MDT reaffirmations, and multilateral maritime activities that impose diplomatic cost on Beijing. The transparency feed supplied the United States, Japan, Australia, the EU, France, the UK, Canada, India, and Korea with evidentiary material for prompt condemnation; the 17 June 2024 incident drew a G7 foreign ministers' paragraph. Yet internationalisation has limits the Philippines openly acknowledges: ASEAN remains divided, with no claimant willing to mirror Manila's confrontational transparency; the United States declined to treat any single incident as triggering the MDT; and the multilateral chorus, however loud, has not altered Chinese behaviour at the level of physical control of features.

  • The central unresolved tension of the period is between deterrence-through-publicity and the risk that publicity itself raises the probability of an MDT-triggering incident — a tension the three competing accounts read in opposite directions. Manila holds that transparency is a principled, lawful defence of sovereign rights that deters by exposing coercion; Beijing holds it is US-instigated provocation that manufactures incidents and raises escalation risk; a small-state-hedging reading holds that transparency is an audience-costs strategy that binds Manila to firmness while outsourcing deterrence to allies it cannot fully control. By the May 2026 corpus cut the confrontation had reached a contingent, unstable equilibrium: resupply continues, the award stands, the laws are on the books, the militia remains — and the next violent incident, whenever it comes, will test whether the doctrine has built deterrence or merely raised the stakes.

2. The Legal Baseline — The 2016 Award and Manila's Revived Invocation

2.1 What the Award Decided

The confrontation of 2023–2026 cannot be read apart from the legal instrument that frames every Philippine claim within it. On 12 July 2016 the arbitral tribunal constituted under Annex VII of the United Nations Convention on the Law of the Sea (UNCLOS), administered by the Permanent Court of Arbitration in The Republic of the Philippines v. The People's Republic of China (PCA Case No. 2013-19), issued its Award on the merits. The tribunal had earlier, on 29 October 2015, found it had jurisdiction over most of the Philippine submissions. The merits award made findings of unusual specificity. It held that China's claim to "historic rights" within the so-called nine-dash line had no legal basis insofar as it exceeded entitlements granted under UNCLOS, because whatever historic rights China may once have had were extinguished upon its accession to the Convention. It held that none of the high-tide features in the Spratly Islands — including the largest, Itu Aba (Taiping), occupied by Taiwan — qualifies as a fully entitled "island" under UNCLOS Article 121(3) capable of generating an exclusive economic zone or continental shelf, classifying them instead as "rocks." It held that Second Thomas Shoal (Ayungin) and Mischief Reef are low-tide elevations lying within the Philippine EEZ and continental shelf, over which China can assert no sovereign claim. It held that Scarborough Shoal is a high-tide feature generating a territorial sea but not an EEZ, and that China had unlawfully prevented Filipino fishermen from their traditional fishing there. And it found that China had aggravated the dispute during the proceedings through its island-building.

These findings are the reason the geography of the 2023–2026 contest is what it is. Every flashpoint examined in this document — Ayungin, Scarborough, Sabina — is a feature the tribunal addressed by name or by category. The award did not, and could not, rule on territorial sovereignty over land features (a question outside UNCLOS jurisdiction), nor did it provide any enforcement mechanism. It is "final and binding" on the parties under UNCLOS Article 296 and Annex VII Article 11, but the Convention furnishes no court bailiff. This gap between bindingness and enforceability is the structural fact within which Manila's revival strategy operates.

2.2 China's Non-Participation and Non-Recognition

China's position, fairly stated, is not a casual dismissal but a developed legal-political stance. Beijing declined to participate in the arbitration from the outset, issuing in December 2014 a Position Paper arguing that the tribunal lacked jurisdiction because the dispute was, in essence, about territorial sovereignty and maritime delimitation — the latter being a subject China had excluded from compulsory arbitration through a 2006 declaration permitted under UNCLOS Article 298. On the day of the award China's Ministry of Foreign Affairs declared it "null and void" with "no binding force," and President Xi Jinping stated that China's territorial sovereignty and maritime rights in the South China Sea would "not be affected" by the award "under any circumstances." China's consistent line since has been that the award is the product of a procedurally illegitimate process, that the question is one of sovereignty over Chinese territory, and that the dispute should be resolved bilaterally between the directly concerned states. This position must be documented as China's institutional logic — not because it prevails as a matter of UNCLOS interpretation (the tribunal addressed and rejected the jurisdictional objections), but because the contest of 2023–2026 is in large part a contest between two states acting on incompatible readings of the award's authority.

2.3 From Dormant Asset to Operational Doctrine

The decisive variable across the three post-2016 administrations was not the award's content, which did not change, but the use to which it was put. Benigno Aquino III had filed the case in 2013 and received the award in the final fortnight of his term. Rodrigo Duterte, inaugurated thirteen days before the award, chose to "set it aside" in pursuit of Chinese investment — famously telling the Chinese that he would "set aside" the ruling temporarily — while never formally repudiating it; his Department of Foreign Affairs continued to file note verbales invoking it. Ferdinand Marcos Jr. inverted the Duterte choice. From his first State of the Nation Address in July 2022 onward, his administration invoked the award as the foundation of Philippine maritime claims and built the 2023–2026 strategy around treating it as operative law rather than a discretionary bargaining chip. Antonio T. Carpio, the former Supreme Court justice who had become the award's most relentless public advocate, supplied the jurisprudential frame in columns and lectures; Jay L. Batongbacal of the UP Institute for Maritime Affairs and Law of the Sea applied it to specific incidents. The revival's culmination was legislative: the November 2024 Maritime Zones Act (Section 9) wrote the award's geographic findings into Philippine statute, converting a diplomatic asset into domestic patrimony that future administrations cannot quietly discard.

3. The Doctrine — "Assertive Transparency" and the National Maritime Council

3.1 The Logic of Publicity

"Assertive transparency" — also rendered "transparency initiative" in official usage — is the organising doctrine of the period and the principal Philippine innovation in the contest. Its premise is that the gray-zone tactics China employs (Section 8) depend for their effectiveness on ambiguity: coercion conducted by white-hulled coast-guard and civilian-flagged militia vessels, below the threshold of armed attack, in waters whose status is contested, is hard to attribute, hard to characterise, and easy to deny. The Philippine response was to strip away the ambiguity by documentation. Each incident would be recorded on video, photographed, geo-located, and attributed to specific vessels by hull number, then released publicly — to Philippine and international media — within hours rather than weeks. The doctrine reversed the Duterte-era preference for "quiet diplomacy," whose theory had been that public confrontation hardened Chinese positions and forfeited the cooperative dividends of accommodation.

The strategic theory of assertive transparency rests on four mechanisms. First, deterrence by reputational cost: publicity imposes a price on coercion by exposing it to international audiences, on the wager that Beijing values its image as a responsible power enough to moderate conduct that is broadcast. Second, evidentiary supply: real-time documentation furnishes the United States, Japan, Australia, the EU, and others with material to issue prompt, specific condemnations, converting each incident into a coordinated diplomatic event. Third, domestic legitimation: visible Chinese aggression builds the public consent — measured by Pulse Asia and Social Weather Stations surveys showing consistently high majorities favouring the assertion of West Philippine Sea rights — on which the political sustainability of the policy depends. Fourth, lawfulness signalling: by documenting that Philippine vessels were conducting routine, lawful activity within the Philippine EEZ when attacked, the strategy reinforces the legal narrative anchored in the 2016 award.

The doctrine also carries an implicit theory of asymmetry. The Philippines cannot match the China Coast Guard in tonnage, the maritime militia in numbers, or the People's Liberation Army Navy in firepower; what it can do is compete in the one domain where a small state can match a great power — the contest for the international narrative and the moral framing of conduct. Assertive transparency is, in this sense, an explicit substitution of informational capacity for material capacity. It converts the very feature that makes gray-zone coercion attractive to Beijing — its plausible deniability, its sub-threshold ambiguity — into a liability, by making each act legible, attributable, and quotable. The doctrine's intellectual lineage runs through the Philippine legal-academic community — Carpio's insistence that the award be treated as living law, Batongbacal's incident-by-incident jurisprudential commentary — and through the recognition, after the 2012 Scarborough loss, that informal understandings and quiet channels had failed precisely because they left no public record against which China could be held. Transparency was, at bottom, a decision never again to lose a feature in silence.

3.2 The Communications Apparatus

The doctrine's public face was the Philippine Coast Guard, and within it Commodore Jay Tarriela, designated PCG spokesperson for the West Philippine Sea. Tarriela's verified account on X (formerly Twitter) became the de facto real-time channel through which incident footage and attributions reached the world; major international wires — Reuters, the Associated Press, Agence France-Presse, Bloomberg — built newsroom workflows around it. The PCG embedded journalists, both Filipino and foreign, aboard resupply and patrol missions, so that incidents were witnessed and filmed by independent press rather than reported only through government channels. The deliberate choice to lead with the white-hulled Coast Guard rather than the Navy was itself doctrinally significant: it cast the Philippine presence as civilian law-enforcement and sovereignty assertion rather than military projection, keeping the Philippine posture below the same armed-conflict threshold China exploited, and denying Beijing the narrative that Manila was militarising the dispute.

3.3 The National Maritime Council

The institutional consolidation of the doctrine came in 2024 with the creation of the National Maritime Council (NMC), succeeding the looser National Task Force for the West Philippine Sea (NTF-WPS). [TBD-VERIFY: the NMC was created by Executive Order in March 2024 — reportedly EO No. 57, s. 2024, signed 25 March 2024; confirm number and date.] The NMC drew together the principal agencies of the maritime contest — the Department of Foreign Affairs, the Department of National Defense, the Armed Forces of the Philippines, the Philippine Coast Guard, the National Security Council, and the maritime-domain-awareness apparatus — under a unified coordinating structure. Its establishment marked the transition of assertive transparency from a communications tactic associated with particular officials into a settled instrument of state with a standing bureaucratic home. The NMC's remit spanned the four dimensions of the strategy: the legal (coordinating diplomatic protests and the legislative agenda), the operational (resupply and patrol planning), the diplomatic (allied coordination), and the informational (a unified messaging line). The creation of a council rather than a task force signalled permanence — a deliberate counter to the critique that the strategy was personality-driven and would not survive a change of spokesperson or president.

3.4 The Domestic Politics of the Doctrine

Assertive transparency was never uncontested at home. It was, in part, an implicit rebuke of the Duterte-era posture, and the Duterte camp answered in kind. Former President Rodrigo Duterte — until his March 2025 arrest and transfer to the International Criminal Court on the drug-war matter — characterised the West Philippine Sea contest as a "rich man's quarrel" the Philippines could neither win nor afford to provoke, and defended his own accommodation as the prudent course for a weak state next to a great power. Vice-President Sara Duterte-Carpio echoed elements of this critique in muted form before the 2024 coalition rupture and more pointedly afterward. The pro-China-balancer position — articulated also by the Bayan Muna parliamentary remnant and by academic commentators including Walden Bello and Roland Simbulan — held that publicising incidents inflamed rather than deterred, and that the strategy served allied (chiefly US) interests more than Philippine ones. The contest over the doctrine is treated in full in the three-account reading (Section 11) and intersects the domestic-political frame of PH-D-05.

4. Second Thomas Shoal (Ayungin) — The Resupply War and the 17 June 2024 Incident

4.1 The Grounded Sentinel

Second Thomas Shoal — Ayungin Shoal in Philippine usage, Ren'ai Jiao in Chinese — is a low-tide elevation roughly 105 nautical miles west of Palawan, well within the Philippine 200-nautical-mile EEZ and expressly addressed by the 2016 award as a feature over which China holds no lawful claim. Its strategic centrality derives from a single object: the BRP Sierra Madre, a World War II-era tank-landing ship (formerly USS LST-821 / USS Harnett County) that the Philippine Navy deliberately ran aground on the shoal on 9 May 1999, during the Estrada administration, as a calculated sovereignty marker after China's mid-1990s occupation of nearby Mischief Reef. A small detachment of Philippine Marines — typically eight to ten personnel — has manned the rusting hulk continuously ever since. The vessel is at once an assertion of presence and a standing vulnerability: it cannot sustain itself, and its corroding structure must be resupplied and its garrison rotated by sea. Each such mission — designated a Rotation and Reprovision (RORE) operation — is the periodic trigger around which the Ayungin crisis cycle turns.

4.2 The Resupply Architecture and Chinese Interdiction

The RORE missions typically depart Palawan and are run by the Philippine Coast Guard and contracted or Navy-crewed small craft delivering food, water, fuel, medicine, and rotating personnel. Resupply had proceeded for years without major incident, but from approximately November 2021 the China Coast Guard began systematically interdicting the missions — first with blocking manoeuvres and shadowing, then with water cannon. China's objective was to constrain resupply to "humanitarian" provisions only and to block any cargo — particularly steel, cement, and other construction materials — that could shore up the Sierra Madre's decaying hull and convert the grounded hulk into a more permanent installation. Beijing's underlying position is that the Sierra Madre was grounded illegally in Chinese-claimed waters and that the Philippines committed, in unspecified past discussions, to eventually remove it — a claim Manila rejects. The resupply contest thus became a war of attrition over the physical survival of the vessel itself.

4.3 The 2023 Cycle — Water Cannon, Lasers, and the Transparency Debut

The 2023 cycle established the pattern that would define the period. On 6 February 2023 a CCG vessel directed a "military-grade" green laser at the PCG ship BRP Malapascua during a resupply attempt, temporarily blinding crew members; the PCG's release of the footage was an early, defining instance of the transparency doctrine in action. On 5 August 2023 a CCG vessel deployed water cannon against Philippine resupply boats Unaizah May 1 and Unaizah May 2 roughly 13 nautical miles from Ayungin, forcing the mission to abort. Further water-cannon and blocking incidents followed across the latter half of 2023, including in October and December, with reported minor collisions and damage to Philippine craft. [TBD-VERIFY: precise dates, vessel names, and damage details of the October and December 2023 Ayungin incidents.] Each incident was documented and released, and each generated a corresponding chorus of allied statements — the rhythm of attribution-and-condemnation that the doctrine was designed to produce.

4.4 The 17 June 2024 Boarding

The most violent encounter of the period — and the closest the alliance came to a Mutual Defense Treaty test since 1951 — occurred on 17 June 2024. A Philippine Navy resupply mission to the Sierra Madre, operating rigid-hulled inflatable boats (RHIBs) launched from a larger vessel, was intercepted at close quarters by CCG personnel using their own inflatables. According to the AFP's subsequent account and the video evidence released by the PCG and AFP, CCG personnel boarded the Philippine RHIBs, wielded bladed implements described variously as knives, machetes, and axe-like tools, punctured the inflatable hulls, seized firearms and equipment (including navigation and communications gear), and took cargo intended for the garrison. One Philippine Navy sailor suffered the severance of a thumb during the melee; he was evacuated and underwent surgery. [TBD-VERIFY: the injured sailor has been reported by name (Seaman First Class Jeffrey Facundo) and the severed digit reported variously as the right thumb — confirm name and which thumb against AFP statements.] The Philippine side characterised the boarding as piracy and a deliberate, premeditated assault; the Chinese side characterised its action as lawful "control measures" against an "illegal intrusion" and a "trespassing" resupply mission carrying construction materials.

4.5 The Armed-Attack Question and Escalation Management

The incident's gravest implication was legal-strategic: did it constitute an "armed attack" within the meaning of the 1951 Mutual Defense Treaty, the trigger for US treaty obligations? The Bilateral Defense Guidelines of May 2023 (treated in PH-F-03) had affirmed that an armed attack on Philippine armed forces, public vessels, aircraft, or Coast Guard "anywhere in the South China Sea" would invoke the MDT. After consultation, the Philippine and US governments publicly characterised the 17 June incident as falling short of an armed attack — a calibrated determination that condemned the conduct in the strongest terms while reserving the treaty instrument for a future incident of greater severity (for instance, one involving the loss of Filipino life). The judgement drew criticism domestically — Senator Risa Hontiveros and several Stratbase ADRi commentators argued it was excessively cautious and risked signalling that violence short of killing carried no treaty consequence — while alliance managers defended it as prudent escalation control that preserved diplomatic space. President Marcos himself, in remarks following the incident, stated that the death of a Filipino citizen through "wilful" foreign action would come "very, very close to" an act of war — drawing the red line at lethality while declining to place the 17 June boarding across it. The incident thus became the period's central case study in deterrence-versus-restraint, examined again in the three-account reading (Section 11).

4.6 The July 2026 Ayungin Baton Assault [Recency-sweep update, 2026-08-29]

The provisional-arrangement pause treated in Section 5 did not hold indefinitely. On 20–21 July 2026, a fresh Ayungin resupply encounter produced the most serious documented injury to a Philippine service member at the shoal since the 17 June 2024 boarding. Philippine military and Coast Guard accounts, reported contemporaneously by Al Jazeera, the Philippine News Agency, and other outlets, stated that China Coast Guard personnel struck a Philippine Navy sailor on the head with a wooden baton during the encounter, and that a Philippine Navy rubber boat was damaged in the confrontation. President Ferdinand R. Marcos Jr. publicly condemned the China Coast Guard's conduct at Ayungin. [TBD-VERIFY: precise casualty severity, the sailor's identity and condition, and the exact sequence of the 20–21 July 2026 encounter — search-corroborated via Al Jazeera and Philippine News Agency reporting, dated 20–21 July 2026, but not independently fetch-verified against the primary AFP or PCG incident release in this update.] The Philippines subsequently raised the incident, together with the state of Chinese installations at Bajo de Masinloc (Section 6), directly with Chinese Foreign Minister Wang Yi through diplomatic channels — evidence-tier: search-retrieved, corroborated across the Philippine News Agency and Al Jazeera; not primary-source fetched in this update.

5. The July 2024 Provisional Arrangement and Its Contested Meaning

5.1 The Diplomatic Channel

The 17 June 2024 incident produced not escalation but, within weeks, a managed de-escalation — the period's most instructive demonstration that publicity mobilises pressure but quiet diplomacy resolves crises. Through the latter half of June and July, the two foreign ministries pursued intensive exchanges, channelled on the Philippine side through the DFA's Office of Asian and Pacific Affairs and on the Chinese side through Vice Foreign Minister Sun Weidong [TBD-VERIFY: confirm Sun Weidong as the lead Chinese interlocutor for the July 2024 arrangement]. The product, announced separately by Manila and Beijing on 21–22 July 2024, was described as a "provisional arrangement" governing resupply missions to the Sierra Madre. Notably, no joint text was published — a fact that is not incidental but central to the arrangement's function.

5.2 Two Incompatible Readings of One Arrangement

The arrangement is best understood as a deliberate exercise in constructive ambiguity, each side characterising it to its own advantage. The Philippine version, articulated by Foreign Secretary Enrique Manalo and Department of National Defense officials, held that the arrangement permitted resupply missions to proceed "without prejudice" to the parties' respective sovereignty positions; that the Philippines had not agreed to give Chinese authorities prior notification of resupply missions; and that it had not agreed to allow Chinese inspection of resupplied cargo. The Chinese version, articulated by the Foreign Ministry and the Embassy in Manila, held that the arrangement required Philippine prior notification of resupply missions to the Chinese side, that resupply was limited to humanitarian provisions (food, water, medicine), and that construction materials capable of reinforcing the hulk were excluded. The two readings cannot both be wholly true, and neither party produced a document to adjudicate between them. The ambiguity was the point: it allowed each government to claim it had conceded nothing while permitting resupply to resume.

5.3 What Held and What Did Not

Operationally the arrangement worked, within limits. From late July 2024 the resupply tempo settled into a roughly monthly rhythm with markedly reduced confrontation — the boarding pattern of 17 June was not repeated, and water-cannon use at Ayungin became less frequent. The Philippines, moreover, delivered construction materials to the Sierra Madre in late 2024 — confirmed in AFP resupply manifests — drawing Chinese protest but no physical obstruction, which Manila treated as evidence that its reading (no Chinese veto over cargo) prevailed in practice. Yet the arrangement was narrowly geographic: it covered Ayungin alone, and friction simply migrated to other features, most visibly Sabina Shoal (Section 7), where a CCG water-cannon incident occurred even as the Ayungin tempo calmed. By the May 2026 corpus cut the arrangement had held for nearly two years without resolving anything: the Sierra Madre remained manned, resupply continued, and the sovereignty contest underlying it was exactly where it had been. The arrangement is therefore best read not as a settlement but as a stabilised pause — durable so long as neither side forces the other to define what was left vague, and one bad incident away from collapse.

6. Scarborough Shoal (Bajo de Masinloc) — Standing Standoff and the 2024 Baseline Declaration

6.1 The 2012 Legacy

Scarborough Shoal — Bajo de Masinloc or Panatag Shoal to Filipinos, Huangyan Dao to China — is a triangular reef and lagoon roughly 120 nautical miles west of Zambales in Luzon, well within the Philippine EEZ, though the 2016 award classified it as a high-tide feature generating a territorial sea. It is the original wound of the modern contest. The April–June 2012 standoff — precipitated when the Philippine Navy attempted to arrest Chinese fishermen and was confronted by Chinese maritime-surveillance vessels — ended with a US-brokered understanding that both sides would withdraw. The Philippines withdrew; China did not, and has maintained continuous coast-guard presence and effective control ever since. The 2012 standoff was the proximate trigger for Manila's 2013 decision to file the arbitration, and it remains the cautionary memory against which every subsequent Philippine decision is measured: the lesson the Marcos camp drew was that quiet accommodation and reliance on informal understandings had cost the Philippines a feature, whereas the Duterte camp drew the lesson that confrontation with a superior power ends in loss regardless.

6.2 The Floating Barriers

Across 2023–2024 China tightened its grip on the Scarborough lagoon through the recurrent installation of floating barriers across its mouth, physically excluding Filipino fishing vessels from the traditional fishing grounds the 2016 award had specifically protected. In a publicised operation in September 2023, the PCG cut a barrier and removed it, releasing footage of a diver severing the line — a quintessential transparency-doctrine event that converted an act of enforcement into an international news story and a domestic morale moment. Barriers reappeared and were again contested in 2024. The barrier contest illustrated the doctrine's logic and its ceiling simultaneously: the Philippines could win the narrative of a single cut barrier, but it could not establish durable Filipino access to a lagoon under continuous Chinese coast-guard control. Harassment of Filipino fishing vessels — water cannon, ramming, and blocking — continued around the shoal throughout the period, documented in PCG and Bureau of Fisheries releases, including a reported April 2024 ramming of a Philippine fisheries-bureau vessel. [TBD-VERIFY: the 30 April 2024 ramming of BRP Datu Sanday and the vessel's bureau affiliation.]

6.3 The November 2024 Baseline Declaration

The Scarborough contest escalated from the physical to the legal in November 2024. Four days after President Marcos signed the Maritime Zones Act and Archipelagic Sea Lanes Act on 8 November (Section 9), China announced on 10 November 2024 the publication of "baselines of the territorial sea adjacent to Huangyan Dao" — a straight-baseline declaration drawn around Scarborough Shoal. The declaration was a direct legal counter-move: by enclosing the feature within straight baselines, China asserted a broader claimed maritime entitlement than the territorial sea the 2016 award had found Scarborough generates, and signalled that it would answer Philippine domestic legislation with domestic legal instruments of its own. The Philippine DFA filed a formal protest, characterising the declaration as inconsistent with UNCLOS and the award and "null and void on its face." The exchange converted Scarborough into the clearest example of the period's lawfare dimension: two states asserting incompatible maritime entitlements over the same feature through duelling domestic legal acts, each rejecting the other's, each appealing to third parties for support.

6.4 The July 2026 Water-Cannon Escalation [Recency-sweep update, 2026-08-29]

Days after the Ayungin baton incident (Section 4.6), the confrontation migrated to Scarborough. On 24 July 2026, China Coast Guard vessels used water cannon against Philippine government vessels near Bajo de Masinloc, extending what Philippine reporting characterised as a week of sustained tense encounters across the two features. The sequence — an injury-causing incident at Ayungin followed within days by a separate coercive episode at Scarborough — is consistent with the pattern this document identifies of Chinese pressure migrating across flashpoints rather than concentrating at one (Section 5.3, on the Sabina migration following the mid-2024 Ayungin de-escalation). [TBD-VERIFY: precise vessel identities, hull numbers, and duration of the 24 July 2026 water-cannon deployment — search-corroborated via Philstar reporting dated 24 July 2026, not independently fetch-verified in this update.]

7. Sabina Shoal (Escoda) and the Wider Gray-Zone Theatre

7.1 The BRP Teresa Magbanua Standoff (April–September 2024)

Sabina Shoal — Escoda Shoal to Filipinos, Xianbin Jiao to China — is a low-tide elevation roughly 75 nautical miles west of Palawan and, like Ayungin, within the Philippine EEZ. It became the period's second major standoff in 2024 after Philippine maritime scientists detected what appeared to be early-stage Chinese reclamation activity — patterns of crushed coral and dredge spoil suggesting preparation for island-building of the kind China had conducted at Mischief, Subi, and Fiery Cross in 2014–2017. To deter any reclamation and to assert presence, the PCG forward-deployed its flagship, the 97-metre Japan-built multi-role response vessel BRP Teresa Magbanua, to Sabina from April 2024, sustaining a months-long anchored presence framed as a maritime-domain-awareness and sovereignty mission.

The CCG answered with a sustained pressure campaign — encirclement, blocking, water cannon, and a 19 August 2024 collision between the Teresa Magbanua and a CCG vessel in which both sustained damage. [TBD-VERIFY: the 19 August 2024 collision and the CCG hull number (reported as 5205).] The Teresa Magbanua held at Sabina until mid-September 2024, when it withdrew, the PCG citing crew-rotation, fuel, and supply constraints. Manila characterised the withdrawal as routine; Chinese state media characterised it as a victory in expelling the Philippine vessel. The Sabina standoff is the period's clearest demonstration of the transparency doctrine's operational ceiling: the Philippines did not concede the legal point (Sabina remained, in its view, a low-tide elevation within its EEZ over which China has no claim), but it did concede the operational position, because sustained presence requires a logistical endurance the PCG does not yet possess at scale. Publicity and legal right, the standoff showed, cannot substitute for fuel, food, and hull rotation.

7.2 Whitsun, Iroquois, and the Massing of the Militia

Beyond the named standoffs, the wider theatre is defined by the recurrent massing of Chinese vessels at unoccupied features. Whitsun Reef and Iroquois Reef are the emblematic sites: the March 2021 gathering of more than 220 suspected Chinese maritime-militia vessels at Whitsun established the pattern, and through 2023–2026 the PCG and AFP continued to document militia and CCG presence at Whitsun, Iroquois, Sabina, and adjacent features, often numbering from dozens to hundreds of vessels. These massings are coercion by saturation — asserting de facto presence and control without any single act that could be characterised as an armed attack. The Philippine documentation campaign, drawing on Automatic Identification System (AIS) tracking, satellite imagery, and aerial photography, produced what AMTI and independent analysts regard as the most comprehensive open-source record of this behaviour, precisely because the transparency doctrine made publication of such evidence a standing policy.

7.3 Pag-asa (Thitu) and the Patrol Architecture

Pag-asa Island (Thitu; Zhongye Dao) is the largest Philippine-held feature in the Spratlys, administered as part of the Kalayaan Island Group municipality of Palawan, with a small civilian population and an AFP detachment. It is significant to the period both as a Philippine logistics node and as a recurrent site of Chinese flotilla pressure, with large CCG and militia gatherings observed within a few nautical miles of the island. The AFP Western Command (WESCOM) at Antonio Bautista Air Base in Puerto Princesa coordinates the standing patrol architecture across the KIG. The Philippine framing of these patrols — under operational designations emphasising continuity and presence — positions the AFP and PCG as actively asserting jurisdiction rather than passively responding, reinforcing the narrative that the contest is a Philippine sovereign endeavour supported by allies rather than directed by them.

8. The Gray-Zone Toolkit — CCG, the Maritime Militia, and Law-Enforcement Lawfare

8.1 The Coast Guard as the Lead Instrument

The defining structural feature of the confrontation is that it is fought, on the Chinese side, primarily by the China Coast Guard and the maritime militia rather than the People's Liberation Army Navy — a deliberate design to keep the contest below the threshold of armed conflict and to frame coercion as routine law enforcement. The CCG, reorganised in 2018 to fall under the Central Military Commission via the People's Armed Police, is a paramilitary force operating large, heavily built white-hulled cutters — some among the largest coast-guard vessels in the world, vastly outweighing PCG ships — equipped with water cannon and capable of ramming and shouldering. Its presence at Ayungin, Scarborough, and Sabina is continuous; the PLA Navy typically remains over the horizon, present as a backstop but absent from the immediate incidents. This division of labour is the heart of the gray-zone method: it allows Beijing to assert control while maintaining that no military force is engaged and that the Philippines, by deploying its own Coast Guard and Navy, is the party militarising the dispute.

8.2 The Maritime Militia

Beneath the CCG operates the People's Armed Forces Maritime Militia (PAFMM) — fishing and auxiliary vessels, nominally civilian and commercially registered, that are subsidised, organised, and integrated into the PLA command structure. Their function is to assert presence by numbers, to swarm and block, and to occupy contested waters in a guise that complicates legal characterisation and attribution: a militia vessel can be cast as an innocent fisherman sheltering from weather even as it participates in a coordinated massing. The PAFMM is the instrument behind the Whitsun and Iroquois gatherings and a persistent presence at every flashpoint. The Philippine transparency campaign was in significant part an effort to penetrate this deniability — to demonstrate through tracking and imagery that the "fishing fleets" behave with military coordination, do not fish, and respond to coast-guard direction. Establishing the militia's character as a state instrument rather than a civilian flotilla is itself a contested analytical and legal project, and one the documentation doctrine was built to advance.

8.3 Law-Enforcement Lawfare and the June 2024 CCG Regulation

A distinctive escalation of the period was China's use of its own domestic law as a coercive instrument. On 15 May 2024 China promulgated, effective 15 June 2024, a China Coast Guard regulation (commonly cited as Order No. 3, the "Regulation on Administrative Law Enforcement Procedures of Coast Guard Agencies") asserting authority to detain foreign nationals deemed to have illegally entered Chinese-claimed waters for up to 30 days, extendable to 60 in complex cases, without trial. [TBD-VERIFY: the exact promulgation and effective dates and the detention periods (30/60 days) in the June 2024 CCG regulation.] The regulation was widely read in Manila and among analysts as authorising the detention of Filipino fishermen, coast-guard personnel, and others operating in waters China claims — including waters the 2016 award placed within the Philippine EEZ. Its timing, two days before the 17 June Ayungin boarding, framed that incident in part as a demonstration of the new "law-enforcement" posture. The regulation is the mirror image of the Philippine lawfare strategy: where Manila codified the 2016 award into domestic statute (Section 9), Beijing codified its claimed jurisdiction into domestic enforcement authority. Each act extends a contested international claim into a domestic legal instrument the other rejects, and the two bodies of "law" now collide directly on the water.

The gray-zone architecture also imposes a structural dilemma on the Philippine side that no amount of documentation resolves. Because Chinese coercion is calibrated to remain below the armed-attack threshold — water cannon rather than gunfire, ramming rather than torpedoes, detention regulations rather than declarations of war — the Philippines faces a graduated pressure to which it has no proportionate response that would not itself escalate. To answer water cannon with water cannon, or boarding with boarding, would risk the first exchange of fire and hand Beijing the narrative of Philippine militarisation; to answer with nothing concedes the feature. Assertive transparency was, in part, an attempt to manufacture a third option between capitulation and escalation: to respond not in the kinetic register where the Philippines is weak but in the informational register where it can compete. The June 2024 CCG regulation tightened this dilemma by adding the threat of lawful-looking detention of Filipino personnel — raising the human stakes of every resupply and patrol mission, and testing whether the transparency doctrine could deter not just damage to vessels but the seizure of people. Through the May 2026 cut, no Filipino had been detained under the regulation, but its existence reshaped the risk calculus of every mission into contested waters.

9. The Lawfare Layer — The Maritime Zones Act and China's Rejection

9.1 The November 2024 Statutes

The culmination of the Marcos administration's effort to convert the 2016 award from diplomatic asset into operative law came on 8 November 2024, when President Marcos signed two statutes at Malacañang: Republic Act No. 12064, the Philippine Maritime Zones Act, and Republic Act No. 12065, the Philippine Archipelagic Sea Lanes Act. RA 12064 codifies the Philippine territorial sea (12 nautical miles), contiguous zone (24 nautical miles), exclusive economic zone (200 nautical miles), and extended continental shelf in conformity with UNCLOS, and its text expressly references the 12 July 2016 arbitral award as binding and as supplying the geographic specification of certain zones and features. It provides criminal penalties for violations within Philippine maritime zones, including unauthorised resource exploitation and unauthorised foreign activity. RA 12065 exercises the Philippines' right as an archipelagic state under UNCLOS Article 53 to designate sea lanes for international transit through the archipelago. The Maritime Zones Act in particular is the legislative spine of the legal strategy: it makes the award permanent domestic patrimony, gives Philippine enforcement actions a domestic statutory basis in addition to the international-law basis, and creates — at least on paper — Philippine criminal jurisdiction over foreign actors operating unlawfully within Philippine zones.

9.2 China's Rejection and the Lawfare Exchange

China's response was immediate and twofold. On 8 November 2024 Beijing delivered a diplomatic protest declaring both laws "null and void" and reasserting Chinese sovereignty over the South China Sea features. Then, on 10 November 2024, it announced the Scarborough straight-baseline declaration treated in Section 6.3 — answering Philippine legislation with a domestic legal instrument of its own. The Philippine DFA filed counter-protests at the bilateral level and at the United Nations. The exchange crystallised the period's lawfare dimension into its clearest form: a contest conducted through the deposit of incompatible legal instruments — Philippine statutes invoking the award, Chinese declarations rejecting it and asserting baselines around contested features, each side filing protests against the other and seeking third-party endorsement. The lawfare layer changes nothing on the water by itself; its significance is that it locks in positions, raises the cost of future concessions for both governments, and supplies the documentary architecture within which the operational and diplomatic contests are conducted. For the Philippines it carries a specific domestic-political value: by writing the award into statute passed by Congress, the Marcos administration insulated the maritime claim against the kind of quiet executive de-emphasis that characterised the Duterte years.

10. Internationalisation — The MDT, Allies, and the Multilateral Audience

10.1 The Force-Multiplier Logic

Internationalisation is the mechanism that gives the transparency doctrine its strategic weight. A small state cannot deter a great power by documentation alone; the documentation acquires force only when converted into the coordinated diplomatic and military responses of larger partners. The Philippine strategy was therefore engineered to feed allied governments and multilateral audiences a continuous stream of incident evidence, against which they could issue prompt, specific condemnations and reaffirmations. The 17 June 2024 incident is the model: within forty-eight hours the United States, Japan, Australia, the EU, France, the United Kingdom, Canada, India, and Korea had issued statements, and the G7 foreign ministers' communiqué of late June 2024 included a paragraph on it. Each such cycle imposes a reputational and diplomatic cost on Beijing that no single Philippine action could.

10.2 The Mutual Defense Treaty

The 1951 US–Philippines Mutual Defense Treaty is the ultimate backstop, and its reactivation as a credible instrument for South China Sea contingencies — through the 2019 Pompeo clarification, the 2021 reaffirmation, and the 2023 Bilateral Defense Guidelines (all treated in PH-F-03) — is what makes Philippine firmness sustainable. Each major incident draws a fresh US reaffirmation: the 17 June 2024 boarding produced a statement by Secretary of State Antony Blinken and a Biden–Marcos call. Yet the MDT's role in this period is best understood as deterrent-in-reserve rather than active instrument. The Philippine and US decision to characterise the 17 June incident as short of an armed attack (Section 4.5) was a deliberate choice to keep the treaty in reserve, and the persistence of that determination through subsequent incidents demonstrates that the alliance's preferred mode is escalation management, not treaty activation. The MDT deters by its existence and by repeated affirmation; its actual invocation would represent the failure, not the success, of the strategy.

10.3 The Multilateral and ASEAN Layers

The Japan and trilateral dimensions — the 2024 Reciprocal Access Agreement, the US–Japan–Philippines summit, the multilateral maritime cooperative activities and the "Squad" architecture — are treated in detail in PH-F-05 and PH-F-03; here they figure as the operational and diplomatic expression of internationalisation. What this document emphasises is the limit of the multilateral layer. ASEAN remains divided: the Code of Conduct negotiations grind on without resolution, and no other claimant — not Vietnam, not Malaysia under Anwar Ibrahim, not Indonesia under Prabowo Subianto, despite each having its own incidents with China — has chosen to mirror the Philippine confrontational-transparency posture. Manila's strategy is thus a distinctive Philippine choice rather than an ASEAN consensus, and its isolation within the region is itself a vulnerability: it allows Beijing to cast the Philippines as the outlier provocateur and to pursue bilateral management with the more accommodating claimants. The multilateral chorus, however loud at the level of Western and Northeast Asian partners, has not altered Chinese control of any feature, a limit the Philippine government privately acknowledges even as it banks the diplomatic dividends.

11. Three-Account Reading — Manila, Beijing, and the Small-State-Hedging Lens

Following the corpus discipline for contested topics, this section presents three readings of the confrontation without arbitrating among them. Each is internally coherent and grounded in the logic of its proponents.

11.1 The Manila Account — Principled, Lawful Defence of Sovereign Rights

On the Philippine government's account, the confrontation is the principled, lawful defence of sovereign rights guaranteed by UNCLOS and confirmed by a final and binding international arbitral award, conducted with restraint and transparency and backed by allies bound to the rules-based order. Assertive transparency, on this reading, is not provocation but its opposite: it exposes coercion to international scrutiny precisely in order to deter it without resort to force, keeping the Philippine response in the white-hulled, law-enforcement register rather than militarising the dispute. The 2016 award supplies the legal foundation; the Maritime Zones Act makes it permanent domestic law; the resupply of the Sierra Madre and the presence operations at Sabina assert rights the Philippines unquestionably holds within its own EEZ. The escalation of incidents from 2023 is, on this account, evidence not that the strategy provoked China but that Chinese coercion was already underway and unrelenting under the prior accommodationist posture — that Duterte's quiet diplomacy bought nothing, and that firmness backed by allies is the only response that has imposed any cost on Beijing at all. The 17 June restraint demonstrates Philippine maturity: condemning the conduct, mobilising the world, and reserving the treaty instrument rather than rushing toward war.

11.2 The Beijing Account — US-Instigated Provocation Raising Escalation Risk

On China's account, the confrontation is a US-instigated provocation in which a smaller neighbour, encouraged and emboldened by an external power pursuing its own strategy of containment, has abandoned the bilateral consultative path for theatrical confrontation that manufactures incidents and raises the risk of escalation. The arbitration itself was, on this reading, illegitimate — a procedurally flawed exercise over a matter of territorial sovereignty that lay outside the tribunal's jurisdiction, conducted without China's consent and rightly treated as null. The Sierra Madre was grounded illegally in Chinese waters and the Philippines reneged on a commitment to remove it; the resupply of "construction materials" is an attempt to fortify an illegal outpost; the deployment of the Teresa Magbanua to Sabina was an intrusion into Chinese-claimed waters. China's coast-guard actions are, on this account, lawful "rights protection" and "control measures" against trespass, conducted with restraint of their own — water cannon rather than weapons, control measures rather than lethal force. The transparency campaign is information warfare designed to defame China and to manufacture the international pressure that serves the US objective of drawing the Philippines into an anti-China coalition. The escalation, on this reading, flows from Manila's choice — under Washington's influence — to confront rather than consult.

11.3 The Small-State-Hedging / Audience-Costs Reading

A third reading, drawn from the analytical literature on small-state strategy, treats the confrontation neither as vindicated principle nor as manufactured provocation but as a calculated, risk-laden bet by a weak state managing an asymmetric contest. On this account, assertive transparency is an audience-costs strategy: by publicising incidents and committing rhetorically to firmness before domestic and international audiences, the Marcos government deliberately raises the political price of its own backing down, thereby making its commitments more credible and binding allies to its cause. The strategy outsources deterrence to partners — chiefly the United States — whose treaty obligations the Philippines cannot fully control and whose alliance commitment is subject to the vagaries of US domestic politics (the transactional turn under the second Trump administration being the salient risk, treated in PH-F-03 and PH-F-05). The danger this reading foregrounds is the one the doctrine's critics press: that audience costs cut both ways. By making backing down politically costly and by generating a steady stream of confrontations, the strategy reduces Manila's room for tactical retreat and raises the probability that some incident — a death, a sinking, a seizure — crosses the armed-attack line and triggers a treaty obligation neither ally may wish to honour at the moment it arises. On this reading the confrontation is a genuinely open wager: it has imposed real costs on Beijing and rallied real support, but it has also locked the Philippines onto a course from which graceful exit is hard, and it has not changed who controls the contested features.

These accounts are not reconcilable, and the document does not adjudicate between them. The Manila account is strongest on the law and on the record of prior Chinese coercion under accommodation; the Beijing account captures a coherent (if, under UNCLOS, unsuccessful) jurisdictional logic and the genuine escalation risk; the hedging reading captures the strategic gamble that both of the partisan accounts obscure.

12. Conclusion — Escalation Management and the 2026 Equilibrium

By the corpus's May 2026 cutoff, the West Philippine Sea confrontation had reached a contingent, unstable equilibrium rather than any resolution. The resupply of the Sierra Madre continues under the deliberately undefined July 2024 provisional arrangement; the 2016 award stands as the legal spine of the Philippine claim and is now written into domestic statute; China's rejection of the award and its Scarborough baseline declaration stand opposite it; the China Coast Guard and the maritime militia remain the lead instruments of a contest engineered to stay below the armed-attack threshold; and no contested feature has changed hands since the Philippines' 2012 loss of Scarborough. The transparency doctrine has demonstrably succeeded at three of its four objectives — evidentiary supply, domestic legitimation, and lawfulness signalling — while its fourth and central objective, deterrence by reputational cost, remains unproven: Chinese coercion has continued, abating at Ayungin only when a quiet diplomatic channel produced a tacit accommodation, and migrating to Sabina and Scarborough rather than ceasing.

The defining strategic achievement of the period is escalation management itself. The 17 June 2024 boarding — the most violent encounter since 2012, an incident that maimed a Filipino sailor and could plausibly have been characterised as an armed attack — was contained without triggering the Mutual Defense Treaty and was followed within weeks by a managed de-escalation. That sequence is the period's most important precedent: it established that the Philippines and the United States would condemn loudly, mobilise the world, and yet hold the treaty instrument in reserve, drawing the red line at the loss of Filipino life. Whether that line holds is the open question of the years ahead. The doctrine's critics warn that the steady generation of confrontations raises the probability that some future incident crosses it; its defenders reply that the alternative — accommodation — was tried under Duterte and cost the Philippines a shoal without buying peace.

Recency-sweep addendum (2026-08-29): The equilibrium described above held into the third quarter of 2026 in the sense that no feature changed hands and no incident crossed the armed-attack threshold, but the underlying coercion cycle did not abate: a 20–21 July 2026 encounter at Ayungin produced a baton assault on a Philippine Navy sailor and damage to a Philippine Navy boat, and China Coast Guard vessels deployed water cannon against Philippine vessels near Bajo de Masinloc on 24 July 2026 (Sections 4.6 and 6.4). The Philippines raised both episodes with Chinese Foreign Minister Wang Yi through diplomatic channels. The pattern — injury-causing coercion at one flashpoint followed within days by a separate coercive episode at another — is continuous with, rather than a departure from, the migration dynamic this document identifies across 2023–2026. As of this update no fetch-verified primary-source confirmation of vessel-level detail was available in this session; the episodes are recorded here as search-corroborated (Philippine News Agency, Al Jazeera, Philstar) pending primary-source verification in a subsequent research wave.

The forward view turns on factors largely outside Philippine control. Chinese calibration of acceptable risk; the trajectory of the Taiwan contingency, which would subsume the South China Sea contest entirely; the durability of US alliance commitment under transactional management; the outcome of the 2028 Philippine succession, which will determine whether assertive transparency outlives the administration that built it or is unwound by a successor restoring the Duterte hedge. What the 2023–2026 period settled is narrower but real: the Philippines has chosen, institutionalised, legislated, and internationalised a posture of lawful firmness, and has shown it can sustain that posture through the most violent incident in a decade without losing control of the escalation. What it has not settled — what no Philippine administration can settle alone — is who controls the West Philippine Sea. That contest continues, on the water, in the courts of domestic legislation, and in the international audience the transparency doctrine was built to convene.

For the legal anchor of the 2016 arbitration, see PH-F-02 (when written) and PH-K-05 (when written); for the alliance, EDCA, Squad, and capability dimensions of the same period, see PH-F-03; for the Japan and trilateral layer, see PH-F-05; for the long-arc US alliance, see PH-F-01; for the concurrent domestic politics and the pro-China-balancer critique, see PH-D-05; and for the Chinese-side counter-narrative across three presidencies, see PH-N-03 (when written).

Sources

  1. Permanent Court of Arbitration. The South China Sea Arbitration (The Republic of the Philippines v. The People's Republic of China), PCA Case No. 2013-19, Award of 12 July 2016; and Award on Jurisdiction and Admissibility, 29 October 2015.
  2. Philippine Coast Guard (PCG). Press Releases, Video and Photographic Documentation, and Public Communications on West Philippine Sea Incidents (Ayungin/Second Thomas Shoal, Bajo de Masinloc/Scarborough Shoal, Escoda/Sabina Shoal, Pag-asa/Thitu, Whitsun, Iroquois), 2023–2026; including statements by Commodore Jay Tarriela (PCG Spokesperson for the West Philippine Sea) and successive PCG Commandants Admiral Artemio Abu and Admiral Ronnie Gil L. Gavan.
  3. National Task Force for the West Philippine Sea (NTF-WPS) and National Maritime Council (NMC) (Philippines). Press Briefings, Statements, and Establishing Executive Order, 2023–2026; including the March 2024 reconstitution under Executive Order [TBD-VERIFY: the National Maritime Council was created by Executive Order No. 57, s. 2024, signed 25 March 2024 — confirm EO number and date].
  4. Republic of the Philippines. Republic Act No. 12064 — The Philippine Maritime Zones Act, signed 8 November 2024; and Republic Act No. 12065 — The Philippine Archipelagic Sea Lanes Act, signed 8 November 2024.
  5. Department of Foreign Affairs of the Philippines (DFA). Diplomatic Protests (Note Verbale) and Statements on Chinese Conduct in the West Philippine Sea, 2023–2026; and Statements of Secretary Enrique A. Manalo, 2023–2025.
  6. Ministry of Foreign Affairs of the People's Republic of China (MFA-PRC) and the Embassy of the People's Republic of China in the Philippines. Spokesperson Statements, Position Papers, and the China Coast Guard Statements on the "Ren'ai Jiao" (Second Thomas Shoal) and "Huangyan Dao" (Scarborough Shoal) Situations, 2023–2026; including the November 2024 declaration of "baselines of the territorial sea adjacent to Huangyan Dao."
  7. China Coast Guard (CCG). Public Statements and the June 2024 "Regulation on Administrative Law Enforcement Procedures of Coast Guard Agencies" (Order No. 3), effective 15 June 2024.
  8. Center for Strategic and International Studies (CSIS), Asia Maritime Transparency Initiative (AMTI). West Philippine Sea Trackers, Satellite Imagery Reports, and Analytical Briefs, 2023–2026; including work by Gregory B. Poling, Harrison Prétat, and Andreyka Natalegawa.
  9. Armed Forces of the Philippines (AFP), Western Command (WESCOM). Statements on the Rotation and Resupply (RORE) Missions to BRP Sierra Madre, the 17 June 2024 Incident, and West Philippine Sea Patrols, 2023–2026; including statements by AFP Chief of Staff General Romeo S. Brawner Jr.
  10. Office of the Press Secretary / Presidential Communications Office (Philippines). Statements of President Ferdinand R. Marcos, Jr. on the West Philippine Sea, 2022–2026; including the 17–19 June 2024 statements and the Third and Fourth State of the Nation Addresses (22 July 2024; 28 July 2025).
  11. Poling, Gregory B. On Dangerous Ground: America's Century in the South China Sea. New York: Oxford University Press, 2022.
  12. Hayton, Bill. The South China Sea: The Struggle for Power in Asia. New Haven: Yale University Press, 2014.
  13. Carpio, Antonio T. The South China Sea Dispute: Philippine Sovereign Rights and Jurisdiction in the West Philippine Sea. Manila: Institute for Maritime and Ocean Affairs, 2017 and subsequent editions; and his Philippine Daily Inquirer and Rappler columns, 2023–2026.
  14. Batongbacal, Jay L. University of the Philippines Institute for Maritime Affairs and Law of the Sea (UP-IMLOS) Working Papers and Commentary on Ayungin, Scarborough, and Sabina Incidents, 2023–2026.
  15. Rappler, Philippine Daily Inquirer / Inquirer.net, Philippine Star, Manila Bulletin, ABS-CBN News, GMA News, BusinessMirror. Sustained 2023–2026 reporting on West Philippine Sea incidents and the transparency strategy.
  16. Reuters Manila, Associated Press, Agence France-Presse, Bloomberg, Financial Times, The New York Times. Sustained 2023–2026 coverage, including embedded reporting aboard resupply and patrol missions.
  17. South China Sea Probing Initiative (SCSPI), Peking University; and Global Times, Xinhua. Chinese-perspective counter-narrative sources, 2023–2026.
  18. International Crisis Group (ICG). Asia Briefings and Reports on the South China Sea and Philippines–China Maritime Tensions, 2023–2026.
  19. Stratbase ADR Institute (Manila). Issue Briefs and Pilipinas Conference Proceedings on the West Philippine Sea, 2023–2025; and Pulse Asia / Social Weather Stations (SWS) public-opinion surveys on the West Philippine Sea, 2023–2025.
  20. United Nations Convention on the Law of the Sea (UNCLOS), 1982; and the Philippine and Chinese instruments of ratification and declarations thereunder.
  21. Al Jazeera. "China and Philippines trade accusations after sailor injured at sea." 21 July 2026. [Search-retrieved 2026-08-29; not independently fetch-verified in this session — pending primary-source confirmation.]
  22. Philippine News Agency (PNA). "Marcos condemns China Coast Guard assault of PH Navy man in Ayungin," 21 July 2026; and "PH protests Ayungin incident, Scarborough structure in Wang Yi talks," July 2026. [Search-retrieved 2026-08-29; not independently fetch-verified in this session.]
  23. Philstar.com. "Watch: 2 straight days, China fires water cannon at Philippines vessels," 24 July 2026. [Search-retrieved 2026-08-29; not independently fetch-verified in this session.]
  • PH-H-PRES-03: Ferdinand Romualdez Marcos Jr. — "Bongbong" (1957–)
  • PH-F-03: The Renewed US–Philippines Alliance: EDCA Expansion and the South China Sea Crisis (2022–2025) — alliance/EDCA/Squad/capability anchor; this document deepens the maritime-incident and gray-zone dimension and extends to 2026.
  • PH-F-05: The Philippines–Japan Reciprocal Access Agreement and the US–Japan–Philippines Trilateral (2022–2026) — the trilateral/Japan layer of the internationalisation strategy.
  • PH-F-01: The US–Philippines Strategic Relationship (1898–2024) — long-arc alliance baseline and the MDT instrument invoked in this contest.
  • PH-D-05: The 2025 Midterm Election, the Marcos–Duterte Rupture, and the Sara Duterte Impeachment Saga — concurrent domestic-political frame and the pro-China-balancer critique.
  • PH-F-02: The 2016 South China Sea Arbitration and its Politics (when written) — dedicated legal anchor for the arbitral award.
  • PH-K-05: The 2016 Filing of the South China Sea Arbitration (when written) — decision anchor.
  • PH-N-03: China–Philippines Lens — Through Three Presidents (when written) — Chinese-side counter-narrative.
  • PH-K-06: The March 2025 Duterte ICC Arrest Decision
  • PH-K-07: The January 2013 Philippines–China PCA Arbitration Filing Decision
  • PH-H-PRES-06: Fidel Valdez Ramos — A Biography
  • PH-N-01: The Philippines in International Perceptions — People-Power Icon and Frontline State
  • PH-O-01: Philippines Megatrends — The 2030s Questions
  • TW-F-03: The New Southbound Policy and Taiwan's Southeast Asia Turn
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