Geopolitical Chessboard: How Vietnam Shapes American-Chinese Competition

Kiet H. Lê and Hiep X. Trần

ABSTRACT: Vietnam’s geostrategic position—bordering China and commanding key South China Sea maritime routes—makes it a pivotal actor in shaping great-power competition in Southeast Asia. This article argues that the United States should support Vietnam’s neutrality and strategic autonomy as a means of countering Chinese influence. Unlike prior studies that portray regional states as passive players, this analysis highlights Vietnam’s active role in influencing regional dynamics. Through comparative analysis with the Philippines, using historical case studies, geographic assessments, and policy reviews, the article offers practical insights for military and policy practitioners on how geography shapes alliance formation and strategic competition.

Keywords: geopolitics, United States, China, Vietnam, South China Sea, Southeast Asia

The world stands at a geopolitical crossroads. As US unipolar dominance shifts toward a multipolar landscape, the strategic rivalry between the United States and China has emerged. In this great-power contest, geography continues to dictate outcomes in Southeast Asia, where Vietnam has emerged as a crucial balancer in the regional order. Unlike traditional analyses that portray regional nations as passive victims caught between superpowers, Vietnam’s story reveals a more complex reality. A vital middle power in the region, Vietnam leverages its geographical advantages to influence great-power dynamics, transforming apparent vulnerabilities into strategic assets. Sharing an extensive land border with China while commanding critical South China Sea maritime routes, Vietnam occupies perhaps the most complex geopolitical position in Southeast Asia.¹

China’s aggressive rise has altered regional calculations. Beijing’s sweeping territorial claims through the “nine-dash line,” coupled with its ambitious Belt and Road Initiative, have triggered decisive US responses. From President Barack Obama’s “pivot to Asia” to President Donald Trump’s 2017 Indo-Pacific Strategy to President Joe Biden’s comprehensive regional engagement, Washington has consistently sought reliable partners to counter Chinese hegemony, and Vietnam has emerged as an indispensable partner.

The threat China poses to sovereignty in the region has transformed a once-tense relationship into a partnership. Memories of the March 1988 Gac Ma Naval Battle, where Vietnamese sailors died defending territorial waters against Chinese forces, still resonate. Despite diplomatic normalization between Vietnam and China after the Cold War, territorial disputes continue to generate tensions, positioning Vietnam as a natural counterweight to Chinese expansion. This strategic importance crystallized through successive US presidential visits—Obama’s historic 2016 trip elevating ties to Comprehensive Partnership status, Trump’s 2017 declaration of Vietnam as “the heart of the Indo-Pacific region,” and Biden’s 2023 establishment of a Comprehensive Strategic Partnership.²

Vietnam faces a “geographical curse.” Its proximity to China makes it inherently vulnerable. Yet, it possesses a tradition of resistance against Chinese influence and maintains deeply rooted national sentiments naturally skeptical of Chinese dominance. Vietnam’s geostrategic position makes it pivotal in maintaining the balance of power and maritime stability in Southeast Asia, with profound implications for global interests. The United States, therefore, should commit to supporting Vietnam’s neutrality and strategic autonomy.

This article examines how Vietnam’s geographic position makes it vulnerable to its larger neighbor but also uniquely capable of curbing Chinese landpower and influence in the region; offers a comparative analysis of the relative strategic value of Vietnam and the Philippines, a key regional partner of the United States; and demonstrates how Vietnam’s combination of continental borders and maritime advantages should make it an essential pillar of America’s Southeast Asian strategy. It concludes by considering ways the United States can support Vietnamese neutrality, thereby maintaining the regional balance of power.

A Continental Geopolitical Perspective

Vietnam’s distinctive position, complex terrain, and historical resilience make it an indispensable player in Southeast Asia’s evolving security architecture. Positioned at the crossroads of continental Asia and maritime Southeast Asia, Vietnam connects vast geopolitical spaces and borders Cambodia, China, and Laos. China, France, and the United States discovered the harsh realities of Vietnam’s geographic advantages during twentieth-century conflicts, where its complex topography combined with determined resistance led the Vietnamese to defeat seemingly superior forces. Despite modern military advances, Vietnam’s predominantly mountainous landscape still demands enormous resources and poses significant risks for potential aggressors. This geographic inheritance shapes contemporary strategy. Vietnam maintains vigilant defense capabilities while pursuing strategic autonomy amid intensifying superpower rivalry.³

In terms of landpower strategy, Vietnam’s border with China stretches more than 1,065 kilometers, spanning seven provinces from Dien Bien to Quang Ninh. This border area is characterized by complex mountainous terrain with deep valleys, steep slopes, slippery terrain, narrow mountain ranges, and diverse forest ecosystems prominent in northern and central Vietnam. It accounts for approximately 75 percent of the national territory, creating strategic depth along the north-south axis by providing natural defensive advantages that pose significant tactical challenges for large-scale offensive campaigns. Vietnam’s strategic geography has enabled forces to establish multilayered defense systems and deploy asymmetric warfare strategies, allowing the Vietnamese military to combat France and the United States effectively during the two Indochina Wars.⁴

The Vietnamese Central Highlands region holds an important strategic position. This plateau, with an average elevation of 500–1,000 meters facing the South China Sea, could potentially become a solid natural fortress for military bases established to protect the coast and support operations in the South China Sea. The Central Highlands provide an ideal geostrategic position for deploying modern long-range weapons systems, conducting missile attack campaigns, and establishing logistical bases to support maritime activities in the South China Sea (also known as the East Sea of Vietnam). Recognizing the strategic importance of this region, Military Region 5 of the People’s Army of Vietnam has established a network of military facilities in the Central Highlands to protect the country’s national interests.⁵

Vietnam’s relationship with Laos, its neighbor to the west, bolsters its geopolitical position. The 1977 Treaty of Friendship and Cooperation created a regional alliance that balances against pressure from China—their shared neighbor. Vietnamese leadership views Laos’s geographical position strategically and their bilateral partnership as crucial for establishing a western strategic rear, which would provide defensive depth and maintain Vietnam’s combat capability if maritime threats emerge from the South China Sea.⁶

In the past, China has taken advantage of vulnerable points in Vietnam’s terrain but has failed to sustain its early progress. During the 1979 Sino-Vietnamese War, Chinese forces crossed the border in the Lang Son-Quang Ninh region, causing the town of Lang Son to fall on March 6, 1979. After 27 days of campaigning, China’s “quick strike, quick victory” strategy failed to overcome Vietnam’s complex terrain and forest ecosystems and the Vietnamese forces who knew how to use them to maximum advantage. Thus, Vietnam’s continental terrain—especially its northern border region—allows its military to monitor adversary activities, establish solid defensive positions, and maintain strategic autonomy under pressure from China.⁷

While Vietnam’s terrain and continental position make it a difficult opponent, the country faces what Tim Marshall calls a “geographical curse” due to its shared border with China—a nation with long-held hegemonic ambitions. According to Marshall’s analysis, despite the complex terrain system with mountain ranges forming natural defense lines, favorable geographical corridors still exist for facilitating the deployment of military campaigns from China into Vietnamese territory. History has recorded 23 invasions from the third century BC to the twentieth century, during which China persistently pursued a policy of territorial expansion along the southern axis. In modern history, armed conflicts such as the clash at the Paracel Islands (1974), the Sino-Vietnamese War (1979), and the Gac Ma Naval Battle (1988) demonstrate the tension in Vietnamese-Chinese relations. This asymmetric power structure poses a fundamental security challenge for Vietnam in protecting its sovereignty and territorial integrity.⁸

Diplomatic relations between the two countries have undergone many transformations due to shifts in the international geopolitical structure. During the Cold War, especially the period of the Second Indochina War from 1965 to 1975, they had a strategic alliance based on the foundation of communist ideology and the goal of opposing US intervention. The total value of China’s aid accounted for more than 50 percent of the international aid Vietnam received during the Second Indochina War, with an estimated value of 7 billion rubles.⁹

The Vietnamese-Chinese relationship shifted to confrontation amid the Sino-Soviet conflict. As the two largest communist powers in the world, China and the Soviet Union developed fractures in their relationship, and Vietnam chose to pursue a military alliance with the Soviet Union. This strategic decision prompted China to retaliate by supporting the Khmer Rouge regime in Cambodia to pressure Vietnam from its southwestern flank. The situation escalated further when China initiated the Sino-Vietnamese War marking the culmination of hostilities between the two neighboring countries, which shared the same ideology and had previously collaborated against US intervention.

The process of normalizing diplomatic relations was officially initiated in 1991, after the 1990 Chengdu Conference. Similarities in their political systems, the need for international integration, and shared bilateral economic interests drove the reconciliation. China has been Vietnam’s largest trading partner for more than two decades, with trade revenue of approximately $37.5 million in 1991, multiplying nearly 5,472 times to roughly $205.2 billion in 2024. Nonetheless, Vietnamese-Chinese relations are still influenced by territorial disputes, especially in the South China Sea, leading to a model of cooperation in suspicion—a relationship form characterized by the contradiction between economic cooperation and security tensions.¹⁰

The power disparity between Vietnam and China in the twenty-first century has increased significantly due to Beijing’s economic and military development. Despite Vietnam’s achievements, the gaps in territory size (29 times), population (14 times), and economy (41 times) as of 2023 create a profound asymmetric relationship structure. The economic dependence of Vietnam on the Chinese market further exacerbates its vulnerability in the regional security environment. These factors have forced Vietnam to deploy a “double hedging” strategy, simultaneously maintaining cooperative economic relations with China while strengthening security partnerships with other major powers—particularly the United States—to protect core national interests.¹¹

In this context, the development of Vietnamese-American relations demonstrates strategic flexibility in Hanoi’s foreign policy. Despite facing pressure from China, Vietnamese leadership has carefully cultivated this relationship to create a power balance. Nevertheless, the “four nos” principle in the Vietnamese defense policy—“no joining military alliances, no aligning with one country against another, no allowing foreign countries to establish military bases in Vietnam, and no using force or threatening to use force in international relations”—reflects the country’s determination to maintain its independence and not become a tool in the American-Chinese competition in the region.¹²

In the context of the shifting regional security architecture, Vietnam has become a critical geopolitical nexus in US strategic calculations in the Indo-Pacific. Its geostrategic position also plays a vital role in maintaining international norms and ensuring freedom of navigation and a rules-based order in Southeast Asia.

A Maritime Geopolitical Perspective

Vietnam’s unique maritime position, with a 3,260-kilometer coastline facing the South China Sea, places it at the strategic epicenter of the vital maritime corridors connecting the Indian and Pacific Oceans. Five of the world’s 10 busiest shipping routes traverse or approach the South China Sea, which handles approximately 40 percent of global international trade volume. Any disruption to these maritime routes would create significant ripple effects on global trade by increasing shipping times and logistics costs. The South China Sea encompasses strategic straits such as the Sunda, the Singapore, the Lombok, the Makassar, and particularly the Malacca—a vital maritime chokepoint for shipping flows in Southeast and Northeast Asia.¹³

China’s Interest in the South China Sea

This geostrategic position places China in the “Malacca Dilemma,” exposing Beijing’s core vulnerability in energy security and trade in the face of potential control or a blockade of this strait by rival powers, especially the United States. The Strait of Malacca—an 800-kilometer narrow passage between Indonesia, Malaysia, and Singapore and a strategic lifeline for global supply chains—facilitates approximately 40 percent of global trade, a third of worldwide oil transportation, and passage for 90,000 vessels annually, including 90 percent of China’s commercial goods, especially critical energy supplies such as oil and natural gas. The strait is the most direct route connecting the Indian Ocean with the South China Sea, and it links Africa, Europe, and the Middle East with the Indo-Pacific region. Acutely aware of this strategic vulnerability, China, through its “nine-dash line” claim, has declared that approximately 80 percent of the South China Sea is its territory, though its legality is not recognized and it violates the exclusive economic zones of several littoral states, including Vietnam.¹⁴

China’s strategy to impose regional hegemony involves establishing exclusive control over critical South China Sea shipping routes that are vital to global trade. This approach advances China’s geopolitical ambitions and deters against regional states and international actors who advocate for freedom of navigation and multilateral governance of these strategically important waters. In particular, economic power has exacerbated the maritime power imbalance between China and Vietnam. Although Vietnam has significantly enhanced its naval capabilities, currently ranking 33rd globally in naval fleet size, the capacity gap with China remains substantial. Beijing has emerged as a new naval superpower with the world’s largest naval fleet by number of ships, surpassing the United States, creating overwhelming dominance in the regional maritime power balance and placing Vietnam in a position requiring continuous adjustment of maritime security strategies to protect its sovereignty and maritime jurisdiction in an increasingly fierce power competition environment.¹⁵

China’s unilateral sovereignty assertions in the South China Sea contravene international maritime law and have destabilized regional equilibrium. Two pivotal incidents exemplify escalating Sino-Vietnamese tensions in this strategic waterway. The 2014 HD-981 oil rig deployment in the Paracel Islands violated Vietnam’s exclusive economic zone under UN Convention on the Law of the Sea (UNCLOS) 1982 Articles 57, 76, and 81. This provocative action precipitated maritime confrontations between surveillance vessels and coast guard and intensified diplomatic friction and domestic Vietnamese opposition. International pressure compelled China’s withdrawal on July 16, 2014. The rig operation, however, constituted a diversionary tactic while Beijing militarized seven Vietnamese-claimed Spratly reefs, constructing artificial islands with airstrips, naval facilities, radar installations, and military fortifications.¹⁶

In 2019, China’s Haiyang Dizhi 8 survey vessel breached Vietnamese territorial waters near Vanguard Bank within Vietnam’s 200-nautical-mile exclusive economic zone established under UNCLOS 1982 and reinforced by the July 12, 2016, International Arbitral Tribunal ruling. China deployed patrol vessels to pressure Vietnam and assess response capabilities. Hanoi issued formal diplomatic protests to Beijing and the United Nations, invoking UNCLOS legal frameworks. These incidents demonstrated China’s systematic strategy to expand maritime hegemony through sovereignty boundary challenges, despite the 2016 arbitral ruling. The implications transcend bilateral disputes, fundamentally threatening South China Sea security architecture and challenging established international legal precedents governing maritime territorial boundaries.¹⁷

So, why is Vietnam’s maritime position important to the United States? First, Vietnam possesses a 3,260-kilometer coastline facing the South China Sea—a vast maritime area of approximately one million square kilometers—and legitimate sovereignty claims over the Paracel and Spratly archipelagos, according to UNCLOS 1982. With this advantageous geographical structure, Vietnam has established a strategic position over critical South China Sea shipping routes and can monitor and control these sea corridors, preventing China’s ability to monopolize them.¹⁸

China wants complete control of the South China Sea for four reasons that stem from China’s development trajectory and rise being deeply dependent on maritime trade routes through the sea:

1. China’s economic development momentum creates urgent demands for energy, natural resources, and the transportation of goods that serve its enormous population of more than 1.4 billion people. Chinese leaders have long forecasted an “energy thirst,” with Beijing currently importing nearly 60 percent of its oil, a figure projected to increase to 66.6 percent by 2030 and 75 percent by 2040;¹⁹
2. International trade has become a foundational pillar, and exclusive control of the South China Sea would safeguard strategic shipping routes, ensuring continuity of China’s national supply chains while maintaining resources for the “Chinese Dream” aspiration;²⁰
3. China’s important economic-cultural centers and strategic urban areas are concentrated along the eastern coastal belt; and
4. China’s East China Sea gateway is already constrained by the United States “First Island Chain Strategy,” which uses a series of islands from Japan through Taiwan to the Philippines to contain Chinese naval expansion. The South China Sea, therefore, represents the best potential maritime gateway for Beijing to project power from a “regional” power to a “global” power. Vietnam’s maritime position becomes particularly important since it can establish effective control capabilities over key maritime routes that connect to China’s eastern coastal ports and broader naval ambitions in the South China Sea.²¹

Vietnam’s geostrategic position, therefore, plays a key role in US efforts to counterbalance China’s growing influence in the South China Sea and the broader Southeast Asia region.

Partnership with Vietnam facilitates enhanced US intelligence gathering and surveillance of China’s military-economic activities in the South China Sea region and provides Washington with timely information to respond to potential aggressive actions against freedom of navigation in the South China Sea from Beijing. In essence, Vietnam has become an important “strategic card” in Southeast Asia’s regional security structure. Vietnam’s geo-maritime strategic position will greatly support America’s role in establishing and maintaining a power balance, effectively countering China’s activities aimed at exclusive control of the South China Sea. Recognizing the value of this partnership, Washington upgraded bilateral relations with Vietnam to a Comprehensive Strategic Partnership in 2023, and it began actively re-engaging with the region under Biden after a period of reduced interaction during Trump’s first term (2017–21).²²

US Security Interests in the South China Sea

Japan, arguably the most important strategic ally for the United States in Asia, has a long-standing historical, political, and territorial dispute with China over the Senkaku Islands, which—while full of contradictions and conflicts—has led to Japan’s keen concern for Beijing’s expansionist maritime policies. Japan’s unique archipelagic geography and high dependence on maritime shipping routes through the South China Sea have created a strategic vulnerability to Beijing’s “exclusive control” actions. The South China Sea serves as Japan’s most important shipping route, with approximately 42 percent of Japanese goods transiting the route with primarily raw materials—especially fossil fuels Japan imports to ensure energy stability.²³

If shipping routes in the South China Sea are obstructed, Japanese vessels would need to reroute through the Lombok Strait and Eastern Philippines, increasing transportation costs an additional $600 million annually. If a conflict occurs in the South China Sea and causes all shipping routes through the area to stagnate, Japan would need to spend an additional 50 percent on transportation costs for alternative routes. This situation highlights the importance of US leadership in protecting the core national-ethnic interests of the alliance system.²⁴

China’s militarization strategy in the South China Sea through its “nibbling like a silkworm” tactics creates direct challenges to the principles of freedom of navigation and overflight and affects the security of US allied nations. This situation has prompted allies to enhance defense capabilities through participation in multilateral security mechanisms such as the Quadrilateral Security Dialogue (the Quad), AUKUS (Australia, United Kingdom, United States), and ANZUS (Australia, New Zealand, United States) Security Treaty. Among these, Japan has developed into a pioneering link in the US-led security architecture in the region, while accelerating military modernization to counter increasing pressure from China. When updating its long-term national security strategy policy guidelines in late 2022, Tokyo set a goal to increase the defense budget and related spending to 2 percent of its GDP by fiscal year 2027 and committed to acquiring “counterstrike capabilities” to attack enemy territory (China) directly in emergencies.²⁵

Additionally, the interconnected economic structures of allies in the region (such as Australia, the Philippines, South Korea, and Taiwan) are heavily dependent on strategic maritime sea routes traversing the South China Sea. The United States uses these routes to transport up to $1.2 trillion of the total $5.3 trillion in goods shipped annually. This geo-economic and geostrategic context establishes urgent requirements for the United States in promoting internationalization and establishing a new balance of power in the South China Sea. This strategy aims to protect the interests of the network of allies and partners and maintain the rules-based international order—a core foundation in the global security architecture led by the United States since World War II.²⁶

Vietnam’s Ports

Vietnam’s coastline includes diverse deepwater port systems and strategic positions in the Spratly and Paracel archipelagos, which play a pivotal role in maritime security architecture and protect freedom of navigation in the South China Sea. Vietnam’s coastal terrain extends from north to south, with deepwater port systems that create favorable conditions for deploying long-range naval operations and establishing an important forward logistics line in naval campaigns. The bays and deepwater ports, including Cam Ranh Bay, Nha Trang Bay, Cai Mep Port, Hai Phong Port, Vung Tau Port, and others, play a pivotal role in receiving logistical support and military equipment for naval forces, particularly in the event of large-scale military conflict in the region. Within this strategic port system, Cam Ranh Bay is internationally recognized as an “ideal natural fortress and a defensive fortress of the Pacific” and ranked as one of the world’s top three strategic ports, along with the Port of San Francisco (United States) and the Port of Rio de Janeiro (Brazil). The unique terrain structure with a narrow port entrance creates favorable conditions for defense, and difficult conditions for external attacks allow for comprehensive control of the South China Sea and establish a key strategic defensive position at the intersection between the Pacific and Indian Oceans.²⁷

Recognizing the military value of Cam Ranh Bay during its occupation of Vietnam in the twentieth century, France established Cam Ranh Bay as its main military base in the Far East under Order No. 48/1447 of the French Overseas Ministry (see figures 1 and 2). Military reports emphasized the strategic importance of Cam Ranh Bay for French military operations in Southeast Asia and highlighted the dual role of the base as an internal defense system and a launch pad for offshore naval operations, addressing multidimensional threats. Cam Ranh Bay allows for receiving, supplying, maintaining, and protecting non-permanent air forces participating in activities within the South China Sea, southern South China Sea, and mainland Southeast Asia region, while maintaining an access route to the Gulf of Tonkin.²⁸

Figures 1 and 2. Order No. 48/1447 approving the plan to rebuild, equip, and modernize Indochina and Cam Ranh military base diagram
(Figure 1 source: Final Report of the Base Research Board Established in Saigon, file 10H3388, French Ministry of Defense Archives; and Figure 2 source: Map of Cam Ranh Base in 1951, file 4C1149, French Ministry of Defense Archives, https://www.archives.org.vn/gioi-thieu-tai-lieu-nghiep-vu/su-ra-doi-cua-can-cu-quan-su-cam-ranh-nam-1948.htm.)

For ground forces, Cam Ranh Bay facilitates transportation, supply, and protection of troops in case of intervention in the South China Sea and the Indochina region to address various security threats, including those from hostile nations and internal destabilizing forces. Joslyn Ogden emphasized the geostrategic importance of Cam Ranh Bay when asserting that any entity controlling this bay holds a decisive advantage in the “cat and mouse game” in the South China Sea. For this reason, the United States has long sought access to this strategic deepwater port, recognizing that logistics systems are key factors in large-scale naval campaigns. Historical experience from bases located on Guam and Midway Island in World War II demonstrate the importance of logistics centers for America’s ability to maintain naval power in the Indo-Pacific region. Additionally, the strategic importance of the Paracel and Spratly archipelagos has been recognized since the Japanese Empire occupied these coral islands as part of its expansion strategy into China and Southeast Asia in 1939. The Japanese Empire established a military base on Spratly Island and built a submarine base on Ba Binh (Itu Aba) Island—the largest island in the archipelago. These island entities function as “floating fortresses,” and controlling them would provide any power with a strategic outpost to enhance defense and establish control over critical maritime trade routes in the South China Sea.²⁹

Vietnam’s strategic maritime location provides significant geopolitical advantages for US regional interests and international navigation. The country’s coastal position along vital shipping lanes makes it an important partner in maintaining open sea routes that serve global commerce. Vietnam’s geographic placement also provides the United States with enhanced monitoring capabilities of regional activities and supports multilateral efforts to uphold international maritime law. The recent elevation of US-Vietnam diplomatic ties to a Comprehensive Strategic Partnership demonstrates Washington’s recognition of the valuable role Vietnam plays in the regional balance. Vietnam’s territorial claims over the Paracel and Spratly Islands also ensure a legal basis for US-supported navigation rights, enabling the to coordinate more effectively regional allies to maintain the established international order and the peaceful resolution of maritime disputes through diplomatic channels.

Comparative Geopolitical Analysis: Vietnam and the Philippines

The shift from a unipolar to a multipolar world, marked by the rise of China, has significantly altered Indo-Pacific geopolitics for Vietnam and its neighbor, the Philippines, which occupies a crucial position along vital sea lanes of the South China Sea and is one of the nations most deeply affected by regional power restructuring. In particular, China’s controversial “nine-dash line” has led to territorial disputes over the Scarborough Shoal and the Second Thomas Shoal. As a longtime ally and key element in America’s first island chain strategy, these disputes have placed the Philippines at the center of political tensions and strategic competition between Beijing and Washington.³⁰

The Philippines balances its relations by strengthening its security ties with the United States, participating in multilateral forums—such as the Association of Southeast Asian Nations (ASEAN) and the International Tribunal—and building ties with other major powers. The United States, a long-standing ally with deep historical ties to the Philippines, plays a central role in the archipelagic country’s security strategy. The American-Philippine alliance, solidified through the 1951 Mutual Defense Treaty (MDT), the 1998 Visiting Forces Agreement (VFA), and the 2014 Enhanced Defense Cooperation Agreement (EDCA), created a framework for the US military presence and cooperation in the region. This treaty system underscored the security commitment and allows the United States to maintain influence in the region.³¹

Despite its long history, the American-Philippine relationship has faced numerous challenges, notably the closure of US bases in 1991, reflecting Philippine nationalism and the country’s desire for autonomy. The rise of China as a global power, however, has presented the Philippines with a complex balancing act: maintaining its alliance with the United States while navigating its relationship with China, a territorial rival. With American global power waning and Chinese influence growing, the shifting regional power balance has forced the Philippines to alter its strategy in fluctuating foreign policy approaches under different presidents: Duterte’s pro-China stance versus Marcos’s renewed commitment to the United States and a firmer stance against China.³²

With heightened tensions in the South China Sea, the Philippines has become a crucial US military ally that serves as a front-line state against China’s territorial claims. Both Vietnam and the Philippines are impacted by American-Chinese strategic competition, and their unique geopolitical positions make them key players in constraining China’s expansionist ambitions in Southeast Asia.

Table 1 demonstrates the strategic strengths of Vietnam and the Philippines and reveals two different approaches to navigating American-Chinese rivalry shaped by distinct geographical realities and strategic calculations:

1. Vietnam’s extensive land border with China creates a geopolitical paradox and forces Hanoi into a delicate and pragmatic diplomacy, where every policy decision must account for a neighbor whose military and economic shadow looms large. Historical conflicts spanning millennia have taught Vietnam that survival requires masterful balance rather than blind allegiance to a great power. Conversely, the archipelagic nature of the Philippines provides strategic breathing room with thousands of islands creating natural barriers that offer multiple defensive options and reaction time in potential conflicts.

2. Both nations command critical positions along the world’s busiest shipping corridors, yet their maritime advantages differ significantly. Vietnam’s coastline stretches like a strategic sentinel along vital sea lanes, while the scattered islands of the Philippines form a natural archipelagic fortress that controls access routes. Each country possesses deepwater ports capable of hosting major naval operations. Vietnam’s Cam Ranh Bay, however, is the region’s most coveted strategic prize—a natural fortress that has determined regional power dynamics for more than a century.

3. The contrast in diplomatic trajectories reveals two distinct strategic philosophies. Vietnam has transformed from a Cold War adversary to a strategic partner through careful, consistent diplomacy, while historical legacies ensure measured caution in security commitments. Vietnam’s “four nos” policy represents sophisticated statecraft-maintaining sovereignty while maximizing strategic options. The Philippines, despite its traditional military alliance with the United States, demonstrates policy volatility that shifts with each presidential administration, creating uncertainty in long-term strategic planning.

4. Vietnam offers the United States unique advantages—strategic control over maritime chokepoints, legitimate territorial claims under international law, and middle-power influence that commands regional respect. Nonetheless, economic dependence on China and strict adherence to nonalignment principles limit security cooperation. The Philippines provides direct military access and alliance infrastructure but faces the possibility of direct confrontation, military dependence, and policy inconsistency.

This comparative analysis illuminates how geography shapes destiny in great-power competition. Each nation leverages distinct advantages while managing inherent vulnerabilities in the evolving multipolar order.

United States-Vietnam Relations Moving Forward

Advocating for the United States to request a formal alliance with Vietnam is unrealistic given Vietnamese leadership’s natural caution, the lingering legacy of past conflicts, the geographical constraints Vietnam faces, and its “four nos” policy. Yet, allowing Vietnam to fall into China’s sphere of influence would severely harm US interests in Southeast Asia. Such a scenario would compromise the enormous strategic interests of the United States and its Asian and Western allies in the South China Sea, potentially leading to the complete militarization of these waters under Chinese control. Instead, the United States should support Vietnam’s strategic autonomy, which would serve Vietnamese and American interests while maintaining regional stability.

First, the United States should support Vietnam’s maritime disputes in the South China Sea according to UNCLOS principles. This approach would demonstrate respect for international law while strengthening Vietnam’s position without directly confronting China. In practice, this action would involve the United States consistently voicing support for Vietnam’s legitimate claims based on UNCLOS provisions during multilateral forums such as ASEAN summits, East Asia Summit meetings, and UN General Assembly sessions. The United States could also provide technical assistance to Vietnam in documenting its maritime boundaries and exclusive economic zone claims according to international law standards. Additionally, Washington should continue freedom-of-navigation operations in disputed waters, ensuring these operations remain neutral and law-based rather than appearing to favor any particular claimant. This measured approach would allow the United States to uphold the rules-based international order while avoiding escalatory rhetoric that could provoke Beijing or compromise Vietnam’s delicate balancing act between major powers.

Second, the United States and Vietnam should enhance their naval and military cooperation. Taking a calibrated approach that respects Vietnam’s nonalignment principles, the United States should provide assistance that strengthens Vietnam’s defensive and maritime security capabilities. Practical measures could include expanding the Comprehensive Strategic Partnership to encompass more robust Coast Guard cooperation, joint maritime domain awareness initiatives, and information sharing about regional security threats. The United States could offer advanced maritime surveillance technologies, communication equipment, and radar systems that enhance Vietnam’s ability to monitor its territorial waters without appearing overtly militaristic. Training exchanges between the two navies could focus on defensive capabilities, search-and-rescue operations, and humanitarian assistance rather than offensive military strategies. Furthermore, the United States could facilitate Vietnam’s participation in multilateral naval exercises with other regional partners to build broader security relationships while maintaining its strategic autonomy. This approach would strengthen Vietnam’s defensive posture while avoiding the appearance of a formal military alliance that could trigger Chinese countermeasures.

By providing these types of support, the United States would maintain the balance of power in the region and strengthen its security interests without forcing a confrontation with China that would negatively affect the entire region.

Conclusion

Vietnam has emerged as a pivotal geopolitical asset in America’s strategic competition with China—wielding influence far beyond its modest size. The nation’s rugged Central Highlands terrain serves as a natural fortress and offers ideal platforms for advanced weaponry systems that can dominate South China Sea maritime corridors. This geographical advantage, forged through centuries of conflict, enables Vietnam to navigate the delicate balance between its giant northern neighbor and global superpowers.

Vietnam’s extensive coastline could be America’s strategic gateway to the world’s most contested waters. As massive volumes of global trade flow through South China Sea shipping lanes, Vietnam’s maritime surveillance capabilities provide Washington with invaluable intelligence while safeguarding allied nations’ economic lifelines. The crown jewel remains Cam Ranh Bay—a natural fortress that has historically determined regional power dynamics—alongside the strategically positioned Paracel and Spratly Islands. Unlike the volatile alliance patterns of the Philippines, Vietnam’s calculated diplomacy and “four nos” principle creates a reliable-yet-independent partnership. This geopolitical chess piece provides the United States with opportunities to counter Chinese hegemonic ambitions while respecting Vietnamese sovereignty and regional stability.

Kiet H. Lê
Kiet H. Lê is a PhD candidate at the Faculty of International Studies, University of Social Sciences and Humanities, Vietnam National University, Hanoi, Vietnam. His research interests focus on international relations theory, especially realism and geopolitics in explaining great-power competition.

Hiep X. Trần
Dr. Hiep X. Trần, corresponding author, is an associate professor and lecturer at the University of Da Nang, University of Science and Education, Da Nang, Vietnam. His main research interests include political and international relations issues, Southeast Asia and Indo-Pacific regions, and Vietnam’s international integration.

Endnotes

1. 1. Bashira Omeed, “Emerging Multipolarity: Critical Analysis of a Shifting Global Order,” Centre for Strategic and Contemporary Research, October 22, 2023, https://cscr.pk/explore/themes/politics-governance/emerging-multipolarity-critical-analysis-of-a-shifting-global-order/; Johannes Plagemann, “Introduction to Special Issue: ‘Foreign Policy Signaling in the Indo-Pacific: Responses to the US-China Rivalry in a Multipolar World,’ ” The British Journal of Politics and International Relations 27, no. 1 (2024): 3–19, https://doi.org/10.1177/13691481241306387; Le Hoang Kiet et al., “From Border Conflicts to Maritime Competition: Driving Forces Behind the Power Rivalry Between India and China in the Indian Ocean Region,” Australian Journal of Maritime & Ocean Affairs (2025): 1–25, https://doi.org/10.1080/18366503.2025.2492438; and Encyclopaedia Britannica Online, s.v. “China Sea” by Britannica editors, July 2, 2024, https://www.britannica.com/place/China-Sea.
2. 2. “Remarks by President Trump at APEC CEO Summit | Da Nang, Vietnam,” National Archives, November 10, 2017, https://trumpwhitehouse.archives.gov/briefings-statements/remarks-president-trump-apec-ceo-summit-da-nang-vietnam/.
3. 3. Kiet Hoang Le et al., “Vietnam’s Balancing Strategy in the US-China Rivalry in Southeast Asia,” in Innovations and Tactics for 21st Century Diplomacy, ed. Mohamad Zreik (IGI Global Scientific Publishing, 2025), 271–302, https://doi.org/10.4018/979-8-3693-6074-3.ch012.
4. 4. “Một số thông tin về địa lý Việt Nam” (“Some Information About Vietnam’s Geography”), ASEAN Defence – Military Meeting, November 10, 2019, https://admm.vn/vn/news/detail/!ut/p/z1/rVLBbsIwDP0WDjtGdhrapsf2wNCmwdatK81lipoCGSQtW1S2v1_YnRYkcrFiPfvZ7xkErEBY2euNdLq1culYg-Zuki5xlNEfOM4cvTY7zk2T1OEwrlEACXAYhL6vHMS3Gs_h0EiNq6zm2hksqYO_zWrumtj5L0unFW-lxvla19DkNkTClFkPKETCVNSEIDTmi05lw2cchZcOrY1VpBdRG6HJNIDC 9YnvgGOszDYcC_yGMklR8yPkvxHEHppTpCYdsv421_vVKDOcLDmFP-lPTn4SBS71drXfPjYHU jwzpTFIazX7LL-fFtvd1vJpM_lgxnYQ!!/dz/d5/L2dBISEvZ0FBIS9nQSEh/.
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7. 7. Tim Marshall, Prisoners of Geography (Writers Association Publishing House, 2020), 76–80.
8. 8. Marshall, tù nhân (Prisoners), 76.
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10. 10. Le et al, “Vietnam’s Balancing Strategy”; and “Full Text of Xi’s Signed Article in Vietnamese Newspaper,” The State Council of the People’s Republic of China, April 14, 2025, https://english.www.gov.cn/news/202504/14/content_WS67fc9300c6d0868f4e8f1aaf.html.
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13. 13. Leszek Buszynski, “Geopolitics and the South China Sea,” in The South China Sea: The Geo-political Epicenter of the Indo-Pacific?, ed. N. Hung Son and N. Thi Lan Anh (Springer, 2025), https://doi.org/10.1007/978-981-97-8209-3_1.
14. 14. “The Strait of Malacca, a Key Oil Trade Chokepoint, Links the Indian and Pacific Oceans,” US Energy Information Administration, August 11, 2017, https://www.eia.gov/todayinenergy/detail.php?id=32452; “Thế tiến thoái lưỡng nan ở Malacca: thách thức an ninh lớn đối với Trung Quốc” (“The Malacca Dilemma: China’s Big Security Challenge”), Indo-Pacific Defense Forum, October 27, 2023, https://ipdefenseforum.com/vi/2023/10/the-tien-thoai-luong-nan-o-malacca-thach-thuc-an-ninh-lon-doi-voi-chnd-trung-hoa/; and Vu Thanh Ca, “Armed Conflicts in East Sea Will Be Disastrous,” Vietnamnet Global, August 9, 2019, https://vietnamnet.vn/en/armed-conflicts-in-east-sea-will-be-disastrous-556963.html.
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19. 19. Chien, “Looking Back at the Hai Duong.”
20. 20. Peter Ferdinand, “Westward Ho—the China Dream and ‘One Belt, One Road’: Chinese Foreign Policy Under Xi Jinping,” International Affairs 92, no. 4 (2016): 941–57, https://doi.org/10.1111/1468-2346.12660.
21. 21. Arthur Herman, Pacific Partners: Forging the U.S.-Japan Special Relationship (Hudson Institute, 2017), 104; and Hung Vo Minh et al., “The India-Vietnam-China Geopolitical Triangle and Vietnam’s Measures to Navigate This Relationship from a Two-Level Game Theory Perspective,” Multidisciplinary Reviews 8, no. 3 (2025), https://doi.org/10.31893/multirev.2025079.
22. 22. Ralf Emmers and Catherine Jones, “Evaluating the Prospects for US-Southeast Asia Relations Under the Second Trump Administration,” Asian Survey 65, no. 4–5, (July/August/September/October 2025): 702–27, https://doi.org/10.1525/as.2025.2700690.
23. 23. “How Much Trade Transits the South China Sea?,” ChinaPower, updated January 25, 2021, https://chinapower.csis.org/much-trade-transits-south-china-sea/.
24. 24. Anthony Fensom, “$5 Trillion Meltdown: What If China Shuts Down the South China Sea?,” The National Interest, July 17, 2016, https://nationalinterest.org/blog/5-trillion-meltdown-what-if-china-shuts-down-the-south-china-16996; and “Chính sách của Nhật Bản đối với Biển Đông: Tác động và triển vọng hợp tác cho Việt Nam” (“Japan’s Policy Towards the South China Sea: Impact and Prospects for Cooperation for Vietnam”), South China Sea Research, July 25, 2018, https://nghiencuubiendong.vn/chinh-sach-cua-nhat-ban-doi-voi-bien-dong-tac-dong-va-trien-vong-hop-tac-cho-viet-nam.50146.anews#_ftnref4.
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29. 29. Joslyn Ogden, Institutions in Crisis: Tailhook ’91 and the U.S. Navy (Duke University, The Kenan Institute for Ethics at Duke University, 1991), https://kenan.ethics.duke.edu/wp-content/uploads/2018/01/TailhookUSNavy_Case2015.pdf; Robert F. Rogers, “Guam’s Strategic Value,” Guampedia, https://www.guampedia.com/guams-strategic-value/; and Ian Storey, “Japan’s Maritime Security Interests in Southeast Asia and the South China Sea Disputes,” Political Science 65, no. 2 (2013): 135–56, https://www.tandfonline.com/doiabs/10.1177/0032318713508482.
30. 30. Perfecto Aquino et al, “Strengthening Economic Ties Amidst the Maritime Dispute Between the Philippines and China,” Journal of International Studies 19, no. 2 (2023): 245–75, https://e-journal.uum.edu.my/index.php/jis/ms/article/view/18065.
31. 31. Le Hoang Kiet et al., “From Arroyo to Duterte: Two Decades of Philippines’ Foreign Policy Navigation Between the US and China,” Przegląd Strategiczny 17, no. 1 (2024): 133–50, https://pressto.amu.edu.pl/index.php/ps/article/download/46802/38267.
32. 32. Renato Cruz De Castro, “China’s Belt and Road Initiative (BRI) and the Duterte Administration’s Appeasement Policy: Examining the Connection Between the Two National Strategies,” East Asia 36, no. 3 (2019): 205–27, https://doi.org/10.1007/s12140-019-09315-9; Aileen Baviera, “President Duterte’s Foreign Policy Challenges,” Contemporary Southeast Asia: A Journal of International and Strategic Affairs 38, no. 2 (2016): 202–8, https://muse.jhu.edu/article/628452; and Henry Storey, “Marcos vs Duterte: Domestic Politics Meets Grand Strategy,” Lowy Institute, August 5, 2024, https://www.lowyinstitute.org/the-interpreter/marcos-vs-duterte-domestic-politics-meets-grand-strategy.

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