Introduction
Nearly 11 Countries are battling over resources and sovereignty in the South China Sea (SCS), which is at the heart of one of the most complicated maritime geopolitical conflicts. The Philippines, a major regional player, finds it more and more difficult to preserve its sovereignty over disputed marine areas as a result of China’s forceful territorial claims. Beijing’s refusal to acknowledge the Permanent Court of Arbitration’s (PCA) 2016 ruling (Award), which rejected China’s wide claims under the “Nine-Dash Line,” has escalated conflicts with Philippine vessels and strengthened its control over disputed waters. Manila’s approach has undergone a significant change with the recent passage of the Maritime Zones Act (MZA) and the Archipelagic Sea Lanes Act (ALSA), which attempt to harmonize domestic legislation with the United Nations Convention on the Law of the Sea (UNCLOS).
These Acts define the country’s territorial waters and Exclusive Economic Zone (EEZ) and regulate international traffic via archipelagic sea channels. Beijing, meanwhile, has vehemently disagreed, repeating its territorial claims over the disputed waters and inviting the Philippine envoy. The blog examines the legal, diplomatic, and security implications of the MZA and the ASLA, assessing how these policies uphold Manilla’s claims to sovereignty, impact geopolitics, and affect SCS concerns.
The SCS Dispute
With an estimated $3.37 trillion worth of commodities traveling through its waters each year, it is an essential conduit for international trade it is one of the most strategically important marine areas in the globe is the SCS. It has undeveloped energy resources, such as an estimated 190 trillion cubic feet of natural gas and 11 billion barrels of oil. These geopolitical and economic objectives have spurred multiple countries’ overlapping territorial claims.
Through its “Nine-Dash Line,” a broad maritime claim that includes islands, reefs, and atolls that are claimed by the Philippines, Vietnam, Malaysia, Brunei, and Taiwan, China asserts sovereignty over almost the whole SCS. Regular diplomatic and military conflicts are due to each country’s claims to particular features, such as the Paracel Islands, Scarborough Shoal, and the Spratly Islands. It is predicated on historical assertions from early naval expeditions and antiquated maps. The Award stated that China’s claims were not supported by the UNCLOS. China has ignored the Award, increased its military presence by fortifying and constructing islands, and is still vigorously enforcing its claims, frequently using its coast guard and maritime militia.
Diplomatic and Security Implications of MZA and ALSA
1. MZA
The MZA was implemented to guarantee clear jurisdiction over internal seas, archipelagic waterways, territorial sea, contiguous zone, EEZ, and continental shelf, it was passed to establish the nation’s maritime rights by international law formally. The MZA’s conformity to the Award and UNCLOS, which nullifies China’s Nine-Dash Line claims, is one of its main features. The Philippines improves its legal and diplomatic standing in defending its marine rights and upholding an international system based on rules by incorporating the PCA ruling into domestic law. The MZA strengthens the Philippines’ stance in upcoming SCS talks and disagreements.
China has vehemently opposed the MZA, calling for the removal of the Philippines and restating its claim to historical sovereignty. Its assertions are not legally significant unless supported by widespread international acceptance and successful occupation. This puts China’s historical claims and UNCLOS-supported EEZ definitions in direct legal conflict. It has been noted that China frequently engages in ‘selective compliance’ with UNCLOS, adhering to specific clauses but rejecting decisions that contradict its assertions, thereby undermining its credibility in court cases.
The Philippines’ legal foundation for maritime enforcement is strengthened by the MZA, which may result in more coast guard patrols and run-ins with Chinese ships. “States with clearly defined EEZs have more substantial legal justifications for maritime enforcement under UNCLOS Article 73, which permits boarding, inspecting, and detaining foreign vessels violating EEZ regulations,” according to Robert Beckman. This law upholds the 1951 Mutual Defence Treaty (MDT) relationship between the United States and the Philippines. Ashley Roach argued that the possibility of U.S. engagement in support of Philippine vessels is increased when treaty-based security guarantees are linked to UNCLOS-backed EEZ claims. However, this increases the likelihood of Chinese reprisal since the country may increase its maritime militia activities as part of its gray zone plan.
The potential for China to file counterclaims under UNCLOS dispute settlement procedures presents a future obstacle. China can try to postpone enforcement or negotiate different maritime borders through diplomatic pressure. The Philippines must balance strategic caution and legal enforcement to prevent direct war and strengthen its sovereignty.
2. ASLA
By establishing three main sea lanes throughout the archipelago, the ASLA was passed to control the flow of foreign airplanes and ships through Philippine waters. The law balances environmental preservation, national security, and UNCLOS compliance by ensuring that international maritime traffic adheres to established routes. The ASLA enforces archipelagic sea lanes passage, which requires vessels to stay within specified routes and forbids unauthorized activities like military intelligence collection, in contrast to the more general notion of “innocent passage,” which permits unfettered movement through territorial seas. This framework complies with Article 53, which requires archipelagic states to establish transit routes without unduly limiting freedom of navigation (FON).
By enabling the Philippines to monitor foreign vessels more efficiently, the ASLA improves maritime governance and security. However, restricting transit to three approved routes causes diplomatic issues, especially with Japan and the US, which carry out FON activities in the SCS. By policing these lanes, the Philippines maintains regional security while exercising greater control over its waters and obeying international maritime regulations. Therefore, limiting the number of sea lanes could be interpreted as a calculated attempt to control naval access, which would raise objections from powerful maritime nations.
This regulation may limit military mobility by the US and Japan, which frequently carry out freedom of navigation operations (FONOPs) in the area, which could spark diplomatic protests. In addition, China is probably going to reject the sea lane designations and keep using the unapproved routes, claiming the “historical rights doctrine.” China maintains a broad interpretation of navigational rights, including military operations in contentious seas. Confrontations are more likely if China disregards the ASLA’s sea lane limits, which could lead to Philippine enforcement actions.
The ASLA improves the Philippines’ capacity to control the movement of foreign vessels from a security standpoint, especially concerning Chinese survey ships and maritime militia that operate close to Palawan and Mindoro. Because Article 54 permits archipelagic governments to enforce security and environmental rules on seaplane traffic, the Philippines is legally able to require passing vessels to monitor.
The Philippines may have to take direct enforcement measures if China rejects these maritime routes and continues its invasions, which would pose a serious security danger. As China has consistently disregarded Indonesia’s EEZ claims in the Natuna Islands, highlights that such limitations would incite Beijing to test Manila’s resolve purposefully. China may submit the ASLA for assessment by the International Maritime Organisation (IMO), which would be an additional legal obstacle. According to UNCLOS Article 53(9), the IMO must authorize designated sea routes. Therefore, China may contest Manila’s implementation through procedural objections, delaying enforcement.
China’s Response and Regional Reactions
Because it sees the MZA and ASLA as direct threats to its claims, China has fiercely opposed them. It contends that the laws unlawfully invade its marine area, especially near Spratly Islands and Scarborough Shoal. Reiterating its long-standing stance that the tribunal’s decision is “null and void” under international law, China’s MFA has announced that the MZA’s adoption of the 2016 PCA ruling is illegal. Regarding security, Beijing has recently stepped up Coast Guard patrols and deployed marine militias close to disputed waterways.
According to the country’s deputy foreign minister, Manila’s new marine definitions may violate Malaysia’s rights, especially in light of possible overlaps with its EEZ close to Sabah which could result in diplomatic disputes over territorial limits. Reactions are still diverse within ASEAN. Although they do not publicly support the MZA, Vietnam and Indonesia have been praised for their conformity to UNCLOS, which fortifies ASEAN’s collective legal position against Beijing’s maritime expansionism. Citing the necessity of an Indo-Pacific rules-based system, Japan, the United States, and the European Union have all expressed support for Manila. Nonetheless, ASEAN is still reluctant to adopt a united position, with some countries prioritizing economic relations with China more than geopolitical conflict.
Balancing Legal Strategies and Maritime Power
By incorporating definitions supported by UNCLOS into domestic law, the MZA and ASLA strengthen Manila’s sovereignty and guarantee that the PCA verdict is upheld by succeeding administrations. The Philippines improves its negotiating position in ASEAN and international maritime forums by formalizing its EEZ and sea lanes, which lessens the legal ambiguity China takes advantage of. Manila’s ability to obtain diplomatic support from the US, Japan, and EU—all of whom favor a rules-based Indo-Pacific—is further strengthened by its legal assertiveness. However, the lack of naval resources makes enforcement difficult. The MDT protects the Philippines against China’s gray-zone tactics by deterring aggression but failing to satisfy daily patrol demands adequately. In an increasingly contentious South China Sea, the Philippines’ long-term success will depend on striking a balance between military readiness, diplomatic tenacity, and legal enforcement as it continues to exercise its maritime rights through legal frameworks and strategic alliances.
Arjun Kapur is a fourth-year law student at Maharashtra National Law University, Mumbai.
Picture Credit: The Diplomatic