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South China Sea: Persistent Chinese Maritime Coercion

Time window: Last 7 days · Audience: General analyst · Type: Situation report · DTG: 2026-09-02 10:08Z · Overall confidence: HIGH

BLUF

China is very likely to sustain coercive maritime pressure against Philippine Coast Guard and fishing vessels at Scarborough Shoal and elsewhere in the West Philippine Sea over the next 1 to 3 months. A coercive encounter involving water cannons, blocking, collisions or ramming is likely, while an armed exchange is very unlikely.

Executive summary

Reportedly, Beijing continues to reject the July 2016 UNCLOS arbitral ruling, while the China Coast Guard and PRC maritime militia regularly block and harass Philippine Coast Guard and fishing vessels in the South China Sea. China has deployed a floating structure and buoys around Scarborough Shoal, and its artificial Spratly outposts are reported to have anti-ship and anti-aircraft missile systems. Ferdinand Marcos Jr. has called for a reset in ties with China while Philippine policy retains the arbitral award as a central reference and maintains strengthened security ties with the US, Japan and Australia. Assessment: the supplied reporting supports continued grey-zone coercion rather than imminent armed conflict, although the precise scope of China's maritime claim and the outcome of the USS Higgins operation remain disputed.

Change from previous assessment

No material change since the prior brief. The core forecast that China is very likely to sustain coercive maritime pressure remains at high confidence, and the assessment that an armed exchange is very unlikely remains unchanged. This brief places greater emphasis on the specific coercive methods, the treaty-relevant threshold for an armed attack, and the uncertainty surrounding the geographic scope of China's claim. No prior judgment is retired.

Key judgments

1. China is very likely to sustain coercive maritime pressure against Philippine Coast Guard and fishing vessels at Scarborough Shoal and elsewhere in the West Philippine Sea over the next 1 to 3 months. The China Coast Guard and PRC maritime militia are reported to regularly block and harass Philippine vessels with water cannons, collisions and ramming, while China has deployed a floating structure and buoys around Scarborough Shoal. China also uses coastguard operations, maritime militia pressure and militarised Spratly features to routinise its presence. This is an assessed forecast from a recurring pattern, not evidence of preparations for an imminent attack. Confidence is high because high-confidence major-media reporting is consistent with a high-confidence think-tank assessment of China's operating methods, although the supplied material does not identify a new named encounter during this reporting window. (Confidence: high · ASSESSED)

• I&W: Within 0-14 days, a Philippine Coast Guard or major-media account records China Coast Guard or PRC maritime militia blocking, water-cannon use, collision or ramming involving a Philippine Coast Guard or fishing vessel at Scarborough Shoal or elsewhere in the West Philippine Sea. (0-14 days)
• I&W: A sustained 1-3 month period contains no reported blocking, water-cannon use, collision or ramming, while reporting or imagery shows the floating structure and buoys around Scarborough Shoal have been removed. (1-3 months)

2. China is very likely to continue rejecting the July 2016 arbitral ruling and asserting an expansive claim over the South China Sea. Beijing has described the ruling as invalid or null and void and continues to insist on sovereignty over most of the South China Sea. The reporting gives conflicting descriptions of the claim's geographic scope, ranging from approximately 62% of the sea to virtually the entire sea, so confidence is lower on the precise cartographic interpretation than on China's continued rejection of the ruling. Multiple high-confidence major-media claims support the core assessment, while lower-confidence reporting provides additional but less reliable corroboration. (Confidence: high · REPORTED)

• I&W: Within 0-14 days, an official Chinese statement again says Beijing will not accept or recognise the arbitration decision, or repeats its assertion of sovereignty over most of the South China Sea. (0-14 days)
• I&W: Beijing publicly recognises the ruling or issues a formal position that aligns its maritime claims with the tribunal's findings during the next 1-3 months. (1-3 months)

3. The Philippines is likely to maintain a dual-track policy over the next 1 to 3 months, combining Ferdinand Marcos Jr.'s call for a reset with China with continued reliance on the July 2016 arbitral award and security ties with the US, Japan and Australia. Marcos has elevated the award as a cornerstone of Philippine policy and expanded the Enhanced Defense Cooperation Agreement, while maritime confrontations with China have become more frequent. This is an assessed policy forecast, not evidence that the reset has resolved the dispute. Confidence is medium because the forecast rests on reported policy direction and statements, including a single medium-confidence account of the bilateral defence guidelines, rather than a new formal policy decision. (Confidence: medium · ASSESSED)

• I&W: Within 1-3 months, Marcos repeats the reset call while Philippine policy or senior official statements reaffirm the arbitral award, EDCA or security cooperation with the US, Japan or Australia. (1-3 months)
• I&W: The Marcos government publicly abandons the arbitral award as a policy reference or suspends or reverses EDCA during the next 1-3 months. (1-3 months)

4. An armed exchange between the China Coast Guard or PRC maritime militia and Philippine Coast Guard or other Philippine public vessels in the South China Sea is very unlikely over the next 1 to 3 months. The supplied reporting describes water-cannon use, blocking, collisions and ramming, but does not report an armed attack. The 2023 US-Philippines Bilateral Defense Guidelines state that an armed attack on Philippine armed forces, aircraft or public vessels, including Coast Guard vessels, anywhere in the South China Sea would invoke mutual defence commitments under the 1951 Mutual Defense Treaty. Confidence is medium because the forecast is inferential and time-bound, despite stronger reporting on the coercive pattern. (Confidence: medium · ASSESSED)

• I&W: Within 0-14 days, a credible report documents firearms, explosive force or another deliberate armed attack by Chinese or Philippine forces against Philippine armed forces, aircraft or a public vessel, including a Coast Guard vessel, in the South China Sea. (0-14 days)
• I&W: Over 1-3 months, reported encounters remain limited to water cannons, blocking, collisions or ramming, with no reported armed attack. (1-3 months)

Outlook & scenarios

Continued grey-zone pressure at Scarborough Shoal (75%)

China Coast Guard and PRC maritime militia activity continues against Philippine Coast Guard and fishing vessels at Scarborough Shoal and elsewhere in the West Philippine Sea. A coercive encounter is likely, including blocking, water-cannon use, collision or ramming. An armed exchange remains very unlikely.

Temporary diplomatic restraint (30%)

Ferdinand Marcos Jr.'s reset call gains traction and China and the Philippines temporarily reduce visible confrontations around Scarborough Shoal. Philippine reliance on the arbitral award and security ties with the US, Japan and Australia continues. This scenario is unlikely because the reported coercive pattern and China's rejection of the ruling remain in place.

Collision triggers an acute bilateral crisis (25%)

A collision or ramming involving a Chinese coastguard or maritime militia vessel and a Philippine Coast Guard or fishing vessel produces renewed public protests and pressure on Manila to harden its position. The incident remains below the threshold of an armed attack, preserving the distinction between coercive enforcement and treaty-triggering hostilities.

Taiwan crisis spills into the South China Sea (5%)

If China blockades or forcibly retakes Taiwan, spillover effects in the South China Sea are very likely. This is a low-probability, high-impact wildcard, resting on a single-source expert assessment rather than evidence of current preparations for such a conflict.

Recommendations

1. For the next 0-14 days, maintain a named-incident log for Scarborough Shoal and the West Philippine Sea. Record the vessel, actor, location, manoeuvre, use of water cannons, collision or ramming, damage and each government's account.
2. Apply a clear escalation matrix that separates blocking, water-cannon use, collision and ramming from an armed attack. Treat any reported armed attack on Philippine armed forces, aircraft or public vessels, including Coast Guard vessels, in the South China Sea as an immediate alliance-policy trigger for senior review.
3. Track Philippine policy signals over the next 1-3 months against two separate lines: Marcos's reset language towards China, and continued references to the July 2016 arbitral award, EDCA and security ties with the US, Japan and Australia.
4. When assessing Chinese legal messaging, report the approximately 62% description and the virtually entire South China Sea description as competing formulations. Do not merge them into a single precise estimate without resolving the source discrepancy.
5. Use separate source lines for the USS Higgins operation near Scarborough Shoal. Preserve both Beijing's claim that the destroyer was expelled and the US 7th Fleet account that it continued normal operations, rather than treating either account as independently settled.
6. Do not use the 10 NASA FIRMS thermal detections within the Philippines bounding box as evidence of a maritime attack or attribute them to a specific actor. The data records heat and requires other reporting to establish cause.

Confidence & uncertainty

Overall confidence is high for the core findings on China's continued rejection of the 2016 ruling, recurring coastguard and maritime militia pressure, and the Philippines' dual-track policy. These findings draw on multiple high-confidence claims from major-media reporting, with think-tank reporting supporting the assessment of China's operating methods. The main uncertainties are the conflicting descriptions of the geographic scope of China's claim, the disputed outcome of the USS Higgins operation, and peripheral reporting from lower-reliability sources on Taiwan-related risks and US force posture. The high headline confidence therefore applies to the established pattern and principal outlook, not to every supporting claim.

Intelligence gaps

• [EEI 1.1 · PARTIAL] Number, class, and position (time-stamped) of Chinese Coast Guard (CCG), People’s Armed Forces Maritime Militia (PAFMM), and other PRC paramilitary/auxiliary vessels inside Philippine-claimed EEZ or within 12 nautical miles of Philippine-occupied features (e.g., Scarborough Shoal, Second Thomas/Ayungin Shoal, and other named features). Recommended collection: maritime/AIS
• [EEI 1.3 · PARTIAL] Incidents of Philippine vessels (coast guard, navy, supply boats, civilian fishing vessels) being ordered to alter course, detained, chased, or physically impeded, with time, location, involved units, and damage/injuries if any. Recommended collection: open-source/official statements
• [EEI 1.4 · UNCOVERED] Abrupt changes to vessel identification behavior: AIS transponder deactivations, spoofing, or mismatches between flagged identity and observed equipment/markings among PRC maritime law-enforcement or militia vessels operating near Philippine claims. Recommended collection: maritime/AIS
• [EEI 2.1 · UNCOVERED] Issued directives, patrol orders, or internal guidance from PRC Central Military Commission, PLAN, CCG, or provincial maritime authorities that specify objectives, geographic limits, patrol tempos, or escalation thresholds for operations near Philippine-claimed features. Recommended collection: signals/communications
• [EEI 2.2 · PARTIAL] Public declarations, maritime notices, or newly published 'maritime safety' or exclusion zones, with effective dates and coordinates, issued by Chinese authorities that could be used to justify interdiction or exclusion of Philippine activity. Recommended collection: open-source/official statements
• [EEI 2.3 · UNCOVERED] Evidence of mobilization orders, tasking lists, or logistics planning for Maritime Militia units (vessel requisitions, local fisheries bureau instructions, fuel/resupply manifests) indicating intent to employ militia alongside CCG/PLAN assets. Recommended collection: HUMINT/defense
• [EEI 3.1 · UNCOVERED] Deployment and movement of Philippine Coast Guard and Navy vessels (class, location, on-station times) and scheduled or unscheduled escort/resupply missions to occupied features. Recommended collection: military/AIS
• [EEI 3.2 · UNCOVERED] Air component activity: number and frequency of Philippine air patrol sorties, maritime domain awareness flights, and air-to-surface or maritime strike assets placed on alert or redeployed toward contested areas. Recommended collection: imagery/satellite
• [EEI 3.3 · UNCOVERED] Requests for diplomatic, intelligence, or military assistance from allies (e.g., US, Australia, Japan) including notifications of planned joint patrols, port calls, or freedom of navigation operations with dates and participating units. Recommended collection: open-source/official statements
• [EEI 3.4 · UNCOVERED] Changes to Philippine rules of engagement, emergency law measures, mobilization orders, or civil advisories (evacuations, fishing bans) that alter civilian or military behavior in contested maritime zones. Recommended collection: open-source/official statements

Cited sources

[1] Legis1 · South China Sea Disputes Test U.S. Allies and Defense Commitments (B) · Mon Aug 31 2026 20:15:49 GMT+0000 (Coordinated Universal Time) · sha256:bea7cce73e95 [2] Asia Times · Ten years after award, law and power diverge in South China Sea - Asia Times (B) · Fri Aug 28 2026 03:25:36 GMT+0000 (Coordinated Universal Time) · sha256:11b5ed71e3e0 [3] Center for International Maritime Security (CIMSEC) · The Human Element of Sea Power: Ports, People, and Presence in the South China Sea (C) · Mon Aug 31 2026 10:00:39 GMT+0000 (Coordinated Universal Time) · sha256:569ced1367d0 [4] Daily Kos · Why Taiwan and the South China Sea matter to the US and the world (E) · Sat Aug 29 2026 18:00:00 GMT+0000 (Coordinated Universal Time) · sha256:535b05bb86ba

Source content hashes were computed at collection time; the cited text is preserved unmodified for the life of this product.

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