Troy Elsner, The University of California – Santa Barbara
Abstract
With world trade conducted mostly across seas, escalating geopolitical tensions around major maritime trade routes hold ramifications for the entire world through potential armed conflict and deteriorating economic conditions. Accordingly, robust and effective international maritime law is crucial to maintaining international stability. This paper examines international maritime law through the framework of the United Nations Convention on the Law of the Sea (UNCLOS) in the context of hostility between several nations in the South China Sea (SCS). International enforcement of maritime law by official bodies like the UN and The Hague is weak, as legal rulings are frequently contested and are not directly backed by military bodies. Analyzing economic policy and figures, military strategy, and political action is useful in comparing existing enforcement methods to alternative modes of promoting compliance. The research shows that current economic dynamics hinder comprehensive negotiations and that foreign investments and tariffs help shift power imbalances. While UNCLOS remains the official framework on the law of the sea, its authority is only upheld by collective action by supporting states. In the future, diplomatic conditions must be strengthened to reduce the reliance on military pressure. Joint efforts should be directed towards amending international law to be more punitive and binding to avoid dependence on individual state compliance. Territorial conflict in the SCS underscores the need for change. China’s noncompliance with international arbitrations, competing claims of sovereignty, and the growing involvement of regional and global powers highlight shortcomings in the regulatory abilities of international law. The friction between the U.S., ASEAN states, Japan, and China over economic and geopolitical interests must be met with increased diplomatic pressure, deliberate economic compromise, and consistent joint efforts to counter unjustified encroachment.
Keywords: International maritime law, Sovereignty, Exclusive Economic Zones, Trade
I. Introduction
In an expanding system of international commerce, competition between world powers has heightened with growing interests constrained by an arena of finite space. Boiling points have been reached in wildly active maritime areas. In the South China Sea, China and its smaller neighboring nations like the Philippines, Indonesia, Brunei, and Vietnam have consistently sparred over economic and political sovereignty. The UN has attempted to mediate such conflict through the United Nations Convention on the Law of the Sea, introduced in 1982. However, signatory and non-signatory countries have routinely tried to circumvent this binding international law. Without the pressure of punitive physical action, China has arbitrarily expanded its economic zones. The U.S., a non-signatory of UNCLOS, has been the primary retaliatory agent against China through economic leverage. Recently, the Trump Administration has pushed heavy tariffs not only against China but also against consistent trading partners across the world. This paper aims to outline the history of maritime law and its shortcomings in the modern age of globalization, analyze the failure of international regulatory bodies like the UN and The Hague in addressing rampant noncompliance, and situate localized conflict in the SCS among a broader U.S.-China trade war. It also weighs the potential successes and failures of utilizing economic leverage as a stricter counter to maritime aggression.
II. United Nations Convention on the Law of the Sea
At its inception in 1982, UNCLOS met a glaring need for maritime regulation during the burgeoning globalization of the latter 20th century by serving as an international treaty regulating all maritime activity. The expansion of oceanic resource extraction, primarily fishing, and deep-sea minerals, created a necessity to define national jurisdictions to remedy tensions formed by international economic competition and overlapping claims to territory rights. One of the most significant sections of UNCLOS is its creation of Exclusive Economic Zones (EEZs). These zones encompass an area of 200 miles from a state’s coastline, in which the state has sovereign rights for “exploring and exploiting, conserving and managing natural resources.” UNCLOS also includes key environmental amendments to protect biodiversity and oblige states “to take all measures necessary to prevent, reduce and control pollution of the marine environment from any source.” Though these economic and environmental provisions are comprehensive, they are difficult to enforce. The language of “obligation” within UNCLOS places responsibility on member states to act according to its legal frameworks and recommended modes of compliance. This places a great deal of responsibility on member states, but individual trade cannot be comprehensively monitored on such a granular scale.
Out of the 193 member states of the UN, only 164 are signatories. In the 1980s, U.S. President Reagan refused to sign UNCLOS due to concerns over environmental provisions against deep-sea mining being economically detrimental. The definition of “signatory” does not equate to “strict abider”; the U.S. is not a signatory, yet it has frequently acted as the de facto enforcer against China, a signatory nation. The UN has also attempted to enforce its convention with limited success. The International Tribunal for the Law of the Sea (ITLOS) was built into UNCLOS as an “independent judicial body” to “adjudicate disputes arising out of the interpretation and application of the Convention.” While this tribunal is official, its rulings can be effectively ignored due to the lack of direct military or political power. Like the Hague, it cannot directly compel nations to comply, which results in other nations intervening as regulatory agents.
III. Illegitimate Claims to Sovereignty
Conflict within the SCS is a prime example of the eroded legitimacy of UNCLOS. The primary conflict stems from China’s claims to sovereignty over a vast portion of the SCS. In 1947, the Republic of China drew the 11-dash line, which was altered to become the 9-dash line by the People’s Republic of China in 1952, covering 90% of the SCS and claiming exclusive sovereignty. This is a fundamental friction point with UNCLOS EEZ provisions. By ratifying UNCLOS, China is bound to claims of sovereignty within 200 miles of its coastline, not within 90% of the SCS. In concept, China’s claims to sovereignty did not require direct intervention by international authorities. However, China’s relationship with the Philippines reached a boiling point in 2013 when it began constructing artificial land masses. From December 2013 to October 2015, China built over 3000 acres of artificial landmasses in the Spratly Islands, midway between the Philippines and Vietnam. China aimed to legitimize its sovereignty through these land masses by theoretically expanding its EEZ, The Philippines took China to The Hague in 2016, in which the Permanent Court of Arbitration found that China’s actions were not legally grounded. Despite the gravity of this ruling, China refused to accept it. The artificial land masses and military presence persist in the region, effectively neutralizing The Hague’s decision.
Moreover, China’s noncompliance sets a dangerous precedent that global powers can disregard international rulings without real consequence, leaving smaller, less powerful nations in precarious political and trade positions. Without robust alliances, relatively weaker nations are at the mercy of global powers, as they cannot feasibly defend themselves. In response, the U.S. has conducted routine freedom of navigation operations in the form of military flyovers through the contested region. China has required that states receive approval before any of their military vessels enter the region. Although these operations are the most prominent retaliatory acts against China, they are contradictory. The U.S. conducts these operations to “uphold the rights, freedoms, and lawful uses of the sea recognized in international law.” While the U.S. maintains it acts to defend international law, it has been argued that its position as a non-signatory greatly diminishes its authority as an enforcer. On the other hand, the U.S.’s position as a formidable rival to China is still a significant bulwark against heightened aggression. China has not engaged in violent conflict with the U.S. over these operations, highlighting its understanding of the U.S. as a powerful opponent.
This demonstrates that when international law fails to discipline noncompliant nations, military pressure and presence from powers like the U.S. can be effective. Without these operations, smaller states in the region like the Philippines, Malaysia, and Indonesia, would be subject to the might of the Chinese military. China is further restricted by the U.S.’s mutual defense agreement with the Philippines. In the case of an attack on the Philippines or the U.S., both parties are bound to come to each other’s aid. This type of agreement holds substantial weight in contrast with the agreements between signatory states and the United Nations. Nevertheless, heightened military action creates more potential for serious conflict. This leads to economic strategy as the next potential mode of enforcement.
IV. Economic Competition and Impacts Within the SCS
While legal arbitration and military exercises have placed the SCS in a regional gridlock, it appears that trade relationships have brought economic change but not significant political progress. There are several motivating factors behind China’s determined action and the U.S.’s counteractions. The SCS is a lucrative region with immense value. In 2023, countries in the SCS had an aggregate supply of approximately “3.6 billion barrels of petroleum and other liquids and 40.3 trillion cubic feet (Tcf) of natural gas” in reserves. Countries with these individual reserves include Indonesia, the Philippines, Malaysia, Brunei, China, and Taiwan. The race to strengthen these already substantial reserves is fueled by the prospect of untapped reserves in contested areas such as the Paracel Islands and Spratly Islands. Additionally, the SCS was estimated to see up to 21% of global trade in 2016. With such significant economic activity, it is clear why China, Taiwan, and Vietnam would attempt to prohibit travel by military vessels in this area, as it would undermine their self-declared sovereignty. With its expanding control over this region through several military installments, China generates immense power and leverage while smaller states jockey for their share.
ASEAN, the Association of Southeast Nations, is a political and economic union of Brunei, Cambodia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. As a unified body, it could work to ameliorate the current maritime conflict; however, recent efforts have yielded stagnant outcomes. The ASEAN-China Free Trade Area (ACFTA) of 2002, coupled with sweeping tariff eliminations, has purportedly eased economic tensions between the two bodies by altering market and trade conditions. Although ASEAN and China have continued to amend their agreements, conflicts over sovereignty persist. Since 2002, there has been a diplomatic gridlock over the SCS. Negotiations to establish a code of conduct within the SCS are ongoing. Yet there is no consensus on if the code will be legally binding, or how it will affect external countries. The interests of the two parties draw parallels to current international law in that economic and military advantages tend to overrule the authority of agreements on codified legislation. Moreover, ASEAN’s trade reliance on China serves as a crutch to diplomatic progress. Since 2009, China has been ASEAN’s largest trading partner, with the latter’s trade deficit increasing from $10.4 billion in 2010 to $102.9 billion in 2019. This vast increase represents ASEAN’s tremendous reliance on Chinese imports. This may compel ASEAN to pursue a more lax approach in enforcing SCS code negotiations, as it risks economic punishment if China restricts trade. Ultimately, while improved trade relations between China and ASEAN have eased some tensions, there remains a stalemate in efforts to resolve regional disputes of sovereignty.
V. U.S.-China Political and Economic Relations
While ASEAN and China have struggled to reach a consensus, the environment is still affected by U.S. economic policy. The U.S.’s current trade war with China provides a new lens through which to analyze current and future conflict trends. In 2018, the Trump Administration imposed tariffs on China to diminish its economic growth, prompting manufacturers to relocate to other Southeast Asian countries. This shift in manufacturing location initially damaged China’s exports. Nevertheless, China has only strengthened its position in global trade, experiencing a 7.1% growth in exports in 2024. Still, the relocation of manufacturing centers increases the economic power of smaller countries. This is exemplified by Vietnam. Its “relatively low labor costs, well-developed export infrastructure, and a strategic location on major trade routes” have allowed its economy to flourish, with a GDP growth of 7.09% in 2024. Vietnam’s general growth places it in a better position to negotiate and trade with China due to its capture of manufacturing market power.
This resulting boom of new manufacturing centers is not unique to Vietnam. Manufacturers have moved to Indonesia, Saudi Arabia, and countries in the Middle East, thereby diversifying supply chains. This has immense implications for global trade, as it offsets the power China aims to gain by controlling the SCS. If U.S. freedom of navigation operations (FONOPs) were to stall or decrease in frequency, China would more effectively be able to control the region it claims in the SCS. Importers would not face as much risk from this. The loss of supply centers in China due to sanctions like tariffs and subsequent relocation to other nations ensures that importers can secure imports elsewhere. Since China has less incentive to block or control trade, it has more motivation to improve relations with ASEAN. Ultimately, it should be acknowledged that the Trump Administration’s continued trade war is not devoted to reducing tensions in the SCS. It is domestically driven. Thus, while this policy may incidentally produce improved relations between the affected countries, it should not be regarded as a certain solution.
VI. Tariffs and Adaptation
Continued by the Biden Administration and the current Trump Administration, these tariffs have only grown. On April 2, 2025, President Trump enacted a new series of monumental tariffs. In the face of tariffs, China has maintained its financial military posture. This year, China has proposed a $244.99 billion defense budget, or an increase of 7.2%, outweighing its economic growth target of 5% and following only the U.S.’s proposed $850 billion in defense expenditures. So, despite increased financial pressure, China has continued to bolster its defenses. This signals a more prominent concern for security and awareness of potential threats from heightened military activity in the region. Although China has increased its military expenditures, they are not directed entirely at hostilities with neighboring countries. China has rallied to improve its domestic economy and trade agreements with other countries. This month, Chinese President Xi Jinping is set to visit Vietnam, Malaysia, and Cambodia. Amidst the volatility of Trump’s tariffs, China can capitalize on these visits by portraying itself as a cemented and consistent trading force in the region. He imposed a 10% baseline tariff and reciprocal tariffs on all U.S. trading partners, along with increased tariffs on China to an effective rate of 54%, as of April 3, 2025. This has massive potential to shake global trade.
As the 2018 tariffs prompted supply chains to shift from China, these new tariffs have caught up with them. Suppliers and manufacturers who moved to Vietnam will now face challenges again in recentering or restructuring their operations. It appears that current U.S. policy can spur the region to move in two ways. First, ASEAN and China can strengthen their trade relations to offset the loss imposed by tariffs. They can practice integrating smoother trade, which has already been proven possible by the massive tariff cuts in their current agreements. Also, the U.S. is not the only importing nation globally; other countries are capable of filling its role. However, while there is potential for improved relations, there is also an opportunity to seize greater power. With decreased U.S. economic activity, the next major economic force, China, can flourish. The new tariffs will force emerging supplier nations like Vietnam and Malaysia to find replacement importers. China has the potential to fill this role, which would in turn increase ASEAN’s economic reliance on it. Therefore, while decreased U.S. activity in the region may facilitate trade adaptations, it also produces a power vacuum for China to capitalize on.
VII. Comparative Analysis
Trade relationships based on emerging technology, infrastructure financing, and efforts to create new economic alliances have been pivotal factors in the shaping of international tensions in the SCS. Comparing the methods of U.S. economic strategy to those of China is vital to developing a coherent understanding of regional power dynamics. The U.S. approaches strategy with heavy sanctions. At the end of 2024, the Biden Administration implemented export controls on multiple semiconductor-related equipment vital to defense and technology systems. China retaliated with heightened export control on similar equipment and defense material. Given the timing of Biden’s measures and Trump’s current policies, there is a clear bipartisan precedent on U.S. economic policy toward China. While both countries engage in oscillating policy quarrels, the U.S. conducts more bilateral operations. That is, while the U.S. cooperates with international maritime law, China acts as an independent agent, reducing its coalitional power. China’s military operations in the SCS are not extensively coordinated with neighboring countries.
The U.S. also distinguishes itself because it does not have unlawful claims of sovereignty in the region. As of December 2024, the U.S. has conducted joint FONOPs with Australia, Japan, New Zealand, and the Philippines; these nations all share an interest in upholding international law and ensuring access to trade routes in the SCS. This multilateral approach further reinforces support for UNCLOS and points to a broader backing of U.S. operations. As China independently develops artificial islands and seeks sovereignty, it isolates itself diplomatically. The U.S. has also strengthened its economic relationship with Southeast Asian countries through unified efforts. In 2022, the U.S. initiated the Indo-Pacific Economic Framework for Prosperity (IPEF) with 13 partner countries to promote more robust economic conditions. Several IPEF countries, including Brunei, Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam are also members of ASEAN. Efforts by the U.S. and China to improve relations are consistently mirrored, as displayed by these overlapping alliances. A potential benefit of IPEF is that it adds another trade dimension for ASEAN countries, allowing for less dependence on China. However, China’s economic vision seeks to establish more influence.
China’s Belt and Road Initiative (BRI), initiated in 2013, has seen $1 trillion spent by China toward invigorating economic links around the globe. Through the BRI, China has conducted large-scale debt financing for infrastructure projects, evoking accusations of debt-trap diplomacy. That is, China may use its global economic development efforts to accumulate immense leverage over borrower nations, securing political power without using force. While it may be difficult to predict the eventual outcomes of such massive projects, historical outcomes can help provide a clearer picture. The Belt and Road Initiative can be contrasted with the U.S. Marshall Plan, which invested $13.3 billion, or $150 billion in real terms, in the restructuring of Europe after World War Two. Although the plan benefited the U.S. economy, it helped revitalize Europe and establish stronger trade relationships throughout the 20th century. On the other hand, some borrower countries in the BRI have already succumbed to debt crises. Pakistan developed such a wide budget deficit after BRI loans that it required a bailout from the International Monetary Fund (IMF). If China’s debtors continue to default, their relationships will be strained in the long run.
VIII. Historical Comparison
While conflict in the SCS continues to unfold, historical results can point towards tested, rather than speculative, solutions for the de-escalation of the region. A prime example of maritime dispute resolution is the Cod Wars of 1958-1976 between the NATO members Iceland and the UK. Reliant on fisheries for its economy, Iceland conducted a series of EEZ expansions, reaching 200 nautical miles off its shore by 1976. The UK responded by entering Iceland’s claimed waters and persisting in its fishing operations. The Icelandic naval fleet subsequently equipped its vessels with net cutters, sailed by UK fishing vessels, and cut their nets, rendering them obsolete. Not wanting to resort to war, the UK gave up its efforts, and Iceland prevailed. While not exactly similar to the conflict in the SCS, there are valuable lessons from the Cod Wars. The conflict between Iceland and the UK can be loosely related to that between the Philippines and China. While Iceland did not employ military force, it consistently kept the UK from acting in its waters without restriction. It used diplomatic angles to accuse the UK of violating NATO conduct, which gave it credibility among other member nations. The Philippines and other SCS states can employ this same strategy with the continuation of FONOPs and U.S. presence. While continued U.S. operations may appear inherently inflammatory, the military pressure checks China from taking further action on its claims of sovereignty.
IX. Conclusion
As maritime commerce expands, the enforcement limitations of international law are further exposed. Despite agreements between countries and international organizations, large holes exist in enforcement mechanisms. China continues to claim sovereignty in its expanded EEZs with complete disregard for The Hague’s 2016 ruling. As international law fails, political and economic outcomes are largely dictated by global superpowers. In the SCS, the U.S. has prevailed as the primary deterring force to China. This is a fundamental imbalance as smaller nations aren’t truly protected by the law but by larger nations. This calls for diplomatic restructuring between ASEAN and China; pressure from external parties to complete binding agreements in negotiations can help dictate a clearer code of conduct in the SCS. Next, economic strategy should be employed to produce desirable outcomes. U.S. tariffs on China saw the relocation of supply chains and nodes to other Southeast Asian countries. The decreased reliance of these countries on China helps diminish regional imbalances. As China attempts to improve its position through efforts like the BRI, the importance of agreements like IPEF and U.S. investment is further emphasized. Additionally, multilateral cooperation through actions like FONOPs should be continued to counter aggression. Historical outcomes illustrate that checks on aggressive action with military pressure can still be effective without brutality. Nevertheless, there needs to be a thorough global evaluation of maritime governance.
The Global Affairs Journal 
Leave a comment