The South China Sea Dispute: Philippine Sovereign Rights and Jurisdiction in the West Philippine Sea — Comprehensive Notes (based on Carpio lecture notes)
The West Philippine Sea: Definitions and Context
The term West Philippine Sea refers to the Philippines’ maritime entitlements in the South China Sea, specifically the Territorial Sea, Exclusive Economic Zone (EEZ), and Extended Continental Shelf (ECS) that belong to the Philippines.
The West Philippine Sea is only a part of the broader South China Sea; overlapping claims involve other littoral states as well.
The Legal Framework: UNCLOS and Maritime Zones
UNCLOS is described as the "constitution for the oceans and seas" governing maritime disputes among member states.
Key maritime zones and their breadths (measured from baselines):
Territorial Sea: from baselines (with right of innocent passage for foreign ships).
Contiguous Zone: from the outer limit of the territorial sea (limited jurisdiction for immigration, fiscal, customs, sanitation).
Exclusive Economic Zone (EEZ): up to from baselines (or from the outer limit of the territorial sea); provides specific sovereign rights and jurisdiction within the 188 NM area.
Extended Continental Shelf (ECS): outer limits beyond 200 NM up to a maximum that may extend to 150 NM from the 2,500 m isobath (if the 2,500 m isobath is encountered before reaching 150 NM; in that case ECS not to exceed 100 NM from the isobath).
The Area (deep seabed) is beyond the ECS and is administered by the International Seabed Authority (ISA).
The maximum maritime entitlement a coastal state can claim in the South China Sea, due to geology and geomorphology, is not simply geographic distance but baselines and features; UNCLOS provides the framework for determining these entitlements.
The doctrine under UNCLOS is that the land dominates the sea; maritime zones are measured from land baselines (Article 3, 57, 76).
The concept of LTEs (Low-Tide Elevations) and their special status:
LTEs are not land; they do not generate a territorial sea, airspace, or any maritime zone unless they are within the territorial sea.
LTEs beyond the territorial sea cannot be sovereign territory of any state.
Rocks above water at high tide:
Such rocks generate a 12 NM territorial sea and territorial airspace, but no EEZ unless they meet conditions for habitation/economic life (per Article 121(3)).
The Archipelagic Baselines regime for the Philippines:
Baselines are drawn from outermost points of the archipelago’s islands and drying reefs, with a land-to-water area ratio constraint; waters inside are archipelagic waters with sea-lane passage.
Baselines adjustments under Magallona v. Ermita (2011) established that the Philippines' baselines must conform to UNCLOS III standards, not the pre-UNCLOS Treaty of Paris lines.
The decision rejects using the Treaty of Paris lines as baselines for measuring maritime zones; RA 9522 aligns Philippine baselines with UNCLOS.
Historical Background: Austronesians, Champa Sea, and the Nine-Dashed Line
The West Philippine Sea is contextualized within a long history of Austronesian maritime activity:
Austronesian migrations began ~4,200 years ago, spreading widely by sea with outrigger boats (balangay in the Philippines; vaka in Hawaii; etc.).
The Austronesians originated in Taiwan and spread to the Philippines around a millennium after the development of the Austronesian language.
Austronesian naval technologies (karakoa in the Philippines; coracora in Indonesia) enabled long-distance travel and warfare and trade.
The Champa Sea (ancient name for the South China Sea region) predates the modern naming of the South China Sea; early maps and local names used terms like pulo for islands.
Historical maps show that various European and Asian cartographers labeled Spratlys or other features as belonging to the Philippines (e.g., 1734 Murillo Velarde map; 1744 Murillo Velarde edition; 1852 Islas Filipinas maps; etc.).
Zheng He’s voyages (early 15th century) projected Ming power but did not involve formal territorial claims over sea areas; later scholarship questions any claim of historic rights beyond UNCLOS entitlements.
The Nine-Dashed Line emerged from China’s 1947 map (11 dashes) and was revised to nine dashes after 1950; in 2009, China submitted a map to the UN with the nine-dashed line claiming broad sovereignty and jurisdiction within the line (described as a “national boundary” in 2013 maps by some authorities).
The Core Legal Issue: Historic Rights vs UNCLOS Maritime Entitlements
China’s historic rights claim: asserts rights beyond UNCLOS-derived entitlements within the nine-dashed line, ostensibly grounded in historical usage. This claim has been disputed as lacking UNCLOS support.
The Arbitral Tribunal (Permanent Court of Arbitration) held that:
The nine-dashed line cannot serve as a legal basis to claim maritime entitlements beyond UNCLOS; land-to-sea doctrine requires entitlements to be measured from baselines along the coast.
Historic rights extinguished upon UNCLOS entry into force; historic rights to EEZ and ECS beyond UNCLOS limits are not allowed.
No clear evidence China historically exercised exclusive control over these waters prior to UNCLOS.
The absence of historical evidence does not justify a sui generis right to exploit resources within the nine-dashed line.
The Tribunal emphasized that the dispute is primarily about the interpretation and application of UNCLOS, not sovereignty over islands (except insofar as sovereignty affects maritime entitlements).
The discussion also covers the difference between territorial sovereignty over features and the maritime entitlements those features can generate under UNCLOS (e.g., whether a feature can sustain a population and thus generate an EEZ).
The Arbitration Case (Philippines v. China): Scope, Arguments, and Outcomes
The case, brought under UNCLOS, concerned maritime disputes and interpretations of UNCLOS provisions, not a sovereignty dispute over islands per se.
The Philippines’ five major issues (as summarized in the notes):
1) China’s Historic Rights Claim – The nine-dashed line cannot generate UNCLOS entitlements beyond its main islands.
2) Geologic Features in the Spratlys – None are capable of sustaining a 200 NM EEZ; thus they do not generate overlapping EEZs with Palawan.
3) China-Occupied Geologic Features in the Spratlys – The Tribunal has jurisdiction to rule on their maritime entitlements (LTE vs. High-Tide Elevation) as maritime not sovereignty questions.
4) Scarborough Shoal – A rock above water at high tide; yields a 12 NM territorial sea but no EEZ.
5) Harm to the Marine Environment – China’s actions caused significant environmental harm; the Tribunal assessed and ruled on this under UNCLOS obligations to protect marine environments.
The Tribunal’s key rulings include:
The nine-dashed line has no legal basis to claim maritime entitlements beyond UNCLOS.
ITC (island-like) features cannot automatically grant EEZ unless they meet Article 121(3) criteria (habitation/economic life).
Mischief Reef and Subi Reef are LTEs within the Philippines’ EEZ or ECS; reclamation on LTEs is illegal under UNCLOS if it alters status or rights.
Reed Bank lies within Philippine EEZ; China’s actions to impede exploration and fishing in Reed Bank violated the Philippines’ rights under UNCLOS.
Scarborough Shoal is a rock above water at high tide with a 12 NM territorial sea; Filipino traditional fishing rights within the territorial sea persist regardless of sovereignty.
Enforcement and consequences:
Enforcement of the Award is through multiple channels: UNCLOS state jurisdictions, the International Seabed Authority (ISA), CLCS, and potential diplomatic/academic avenues; the award itself is final and binding, with no appeal unless a bilateral appellate arrangement is agreed.
The Philippines and its allies have a toolbox of options to enforce and/or augment the award (see “Enforcement” section below).
Spratly Islands: Geologic Features and Maritime Entitlements
The Spratlys comprise roughly 750 geologic features; most are submerged; only about 28 features are above water at high tide.
Itu Aba (Taiping Island) is the largest above-water feature; however, the Tribunal found Itu Aba not capable of sustaining a stable community or economic life of its own, and thus not entitled to a 200 NM EEZ.
Key principle: A single Spratly cannot be treated as a single unit for EEZ claims; entitlement depends on the capacity of each feature to sustain habitation or economic life.
The Arbitral Tribunal’s findings on Spratly features:
None of the Spratly features generated a full EEZ; most are Rocks or LTEs with limited or no maritime entitlement beyond 12 NM (territorial sea).
Itu Aba, Thitu, West York (West Is.), Spratly Islands, South-West Cay, and North-East Cay are not capable of sustaining a stable living community under Article 121(3).
LTEs beyond territorial seas are not capable of sovereign ownership and do not generate EEZs; a feature may contribute to a continental shelf if part of the ECS but cannot generate EEZ for itself.
Chinese reclamations on Spratly LTEs (Mischief, Subi) are controversial under UNCLOS because LTEs in the EEZ/ECS of another state cannot be converted into islands with territorial seas; reclamation does not change their legal status.
Scarborough Shoal and Reed Bank: Specific Entitlements and Contested Activities
Scarborough Shoal (Huangyan Island) is a high-tide rock with a maximum 12 NM territorial sea and territorial airspace; it is not capable of sustaining human habitation or economic life of its own; traditional Filipino fishing rights persist in its territorial sea.
Reed Bank (Recto Bank) is within the Philippine EEZ; the area is submerged and part of the continental shelf; it is critical for energy (Malampaya field) and other resources. China's naval and coast guard actions have prevented Philippine-licensed exploration; Reed Bank is not within China’s legal EEZ under UNCLOS.
The arbitration addressed these sites specifically to determine whether they could produce EEZs or not; the Tribunal concluded that Reed Bank lies within the Philippine EEZ and is not subject to Chinese claims beyond UNCLOS entitlements.
Mischief Reef and Subi Reef: LTEs Inside the Philippines’ EEZ and ECS
Mischief Reef is an LTE located within the Philippine EEZ; the Philippines argues it forms part of its continental shelf and is within its EEZ.
Subi Reef is an LTE located outside the Philippine EEZ but within its ECS; the Tribunal concluded that Mischief Reef and Subi Reef are LTEs and that China cannot appropriate an LTE for purposes of generating additional territorial seas or EEZs.
The Tribunal found that China’s reclamation on these LTEs was illegal under UNCLOS, and that only the Philippines may exploit resources within its ECS and EEZ. The Tribunal indicated that China cannot build military installations on LTEs that lie within another state’s EEZ/ECS.
Johnson South, Cuarteron, Gaven, Fiery Cross, and Related Reclamations in the Spratlys
Fiery Cross Reef, Johnson South Reef, and Gaven Reef are high-tide elevations with a 12 NM territorial sea.
Mischief Reef and Subi Reef are LTEs within the Philippine EEZ and ECS; Mischief is within the Philippines’ EEZ and is part of the Philippine continental shelf; Subi is within the ECS.
Reclamations on these LTEs are illegal if they modify entry into land or affect the status of the LTE; the high seas and ECS remain outside the territorial sea unless the feature becomes an island with a legal 12 NM territorial sea.
The Spratlys are described as a breeding ground for marine life; the Spratlys as a protected area via potential Marine Peace Park is discussed as a possible outcome to preserve biodiversity and avoid further ecological damage.
Baselines, Archipelagic Baselines, and the Legal Basis for Philippine Marine Boundaries
Magallona v. Ermita (2011) endorsed UNCLOS-compliant baselines for measuring Philippine maritime zones, rejecting Treaty of Paris baselines that would reallocate the archipelago’s maritime entitlements.
Archipelagic Baselines: The Philippines may draw baselines around its outermost islands and reefs; archipelagic waters lie within these baselines with archipelagic sea lanes for transit, subject to the UNCLOS regime.
The decision highlights the importance of RA 9522 (1998) aligning Philippine baselines with UNCLOS, enabling legally recognized delimitation of maritime zones consistent with the Constitution.
Historical Maps and the Weight of Evidence in UNCLOS Disputes
A large collection of maps from the 16th to 19th centuries illustrates how cartography depicted Spratlys and other features as Philippine territory; arguments about the weight of maps in establishing sovereignty are nuanced:
Maps can be extrinsic evidence of state will, and their binding force depends on their status (official annexes, etc.).
The principle of estoppel can bind the publishing state, but unilateral maps do not by themselves create sovereignty; sovereignty arises from occupation, effective administration, and adherence to UNCLOS regimes.
Murillo Velarde (1734) map, Panacot and Los Bajos de Paragua (Spratlys) as Philippine features are cited; other historical maps show the Spratlys as part of the Philippines.
The document emphasizes that history and maps do not override UNCLOS provisions; discovery alone cannot vest title without continuous and peaceful sovereignty or occupation.
Environmental Impact and the Arbitral Ruling on Marine Environment
The Arbitral Tribunal found that China violated UNCLOS obligations to protect and preserve the marine environment by dredging, reclaiming, and building artificial islands on seven reefs, and failure to prevent endangered species harvesting by Chinese fishermen.
The Tribunal used UNCLOS Article 123 (cooperation in enclosed/semi-enclosed seas) and Article 192 (protection of the marine environment) to justify environmental protections and remedies.
The Tribunal noted that the South China Sea is a semi-enclosed sea, so Parties have mutual obligations to cooperate on resource management and environmental protection.
It also highlighted the significant ecological damage (coral reef loss) from reclamation and dredging, calling it irreversible in many cases.
Enforcement, Aftermath, and Potential Paths Forward
The Arbitration Award is final and binding under UNCLOS; China’s opt-out in 2006 does not nullify the Award.
Potential enforcement avenues discussed in the notes:
Move to suspend China’s ECS or ECS claims via the UN CLCS if China’s ECS overlaps with Philippine ECS and if China does not comply with the award.
File lawsuits in UNCLOS-compliant venues or courts with jurisdiction over infringements in the Philippines’ EEZ.
Apply the United States–Philippines Mutual Defense Treaty (MDT) if Philippine ships or coast guard vessels are attacked; MDT interpretation suggests defense commitments could cover actions in the South China Sea as part of the Pacific region.
Negotiate new maritime boundaries with Malaysia (EEZ) and Vietnam (ECS) to reflect the Tribunal’s rulings that Spratlys do not generate EEZs; adopt a cooperative approach to resource development.
Initiate joint development arrangements (without conceding sovereignty) in zones outside active Philippine EEZ to maximize resource exploitation and avoid direct confrontation, subject to Philippine constitutional constraints.
Build a regional security architecture with ASEAN partners to balance power and ensure peaceful dispute resolution.
The notes emphasize that unilateral declarations or acquiescence may be interpreted as acceptance of boundaries or de-facto arrangements; thus, careful, formal protest is necessary to prevent acquiescence by other states.
Core Implications: Legal, Ethical, and Practical
The core legal impact is that UNCLOS governs maritime entitlements; aggressive nationalist maps and claims cannot supersede UNCLOS rules.
Ethically, the case underscores upholding the rule of law in international relations and avoiding unilateral actions that harm the global commons (the high seas and the seabed).
Practically, the arbitration demonstrates that smaller states can leverage international law to protect their entitlements from more powerful neighbors; joint development and regional cooperation are potential pathways for stability and resource security.
The broader geopolitical implications include: the role of the United States and other great powers in freedom of navigation, the emergence of coast guard diplomacy, and the push toward regional security architectures to maintain peace and stability in Southeast Asia.
List of Acronyms and Key Terms (selected)
ADIZ: Air Defense Identification Zone
ASEAN: Association of Southeast Asian Nations
CLCS: Commission on the Limits of the Continental Shelf
CNOOC: China National Offshore Oil Company
ECS: Extended Continental Shelf
EEZ: Exclusive Economic Zone
ITLOS: International Tribunal for the Law of the Sea
KIG: Kalayaan Island Group
LTE: Low-Tide Elevation
NM: Nautical Miles
PLA: People’s Liberation Army
SC: Secretariat/Center (context-dependent in sources)
UNCLOS: United Nations Convention on the Law of the Sea
UNESCO: United Nations Educational, Scientific and Cultural Organization
U.S.: United States of America
VO: (context-dependent in sources)
Glossary of Geographic Names (selected)
Scarborough Shoal (Huangyan Island)
Itu Aba (Taiping Island)
Paracels (Xisha Islands)
Spratlys (Nansha Islands)
Reed Bank (Recto Bank)
Mischief Reef (Panganiban Reef)
Subi Reef (Zamora Reef)
Fiery Cross Reef (Kagitingan)
Johnson South Reef (Mabini Reef)
Macclesfield Bank (Xian Sha/ central bank)
Pagasa Island (Thitu Island)
Final Takeaway: Core Message of Carpio’s Notes
The South China Sea dispute is fundamentally about the lawful interpretation and application of UNCLOS, not merely historical claims or maps.
China’s nine-dashed line claim cannot generate UNCLOS-based maritime entitlements; historic rights are extinguished by UNCLOS, and land dominates the sea in terms of entitlement calculation.
The Philippines’ arbitration victory reinforces the importance of peaceful dispute resolution and adherence to international law to safeguard national maritime entitlements.
A constructive way forward includes joint development, multilateral security architectures, and a reinforced commitment to **rule-of-law-based