WILL THE U.S. PROTECT ITS ALLY IN A WAR WITH CHINA OVER THE MARITIME ROW?
Constraints and limitations of U.S. support
"Any attack on Philippine aircraft, vessels, or Armed Forces in the South China Sea would invoke our mutual defense treaty."
-Former U.S. President Joe Biden, first U.S.-Japan-Philippines Trilateral Summit
"The U.S. has no right to get involved in a problem between China and the Philippines... Should the U.S. defend the Philippines, its actions must not hurt China's sovereignty and maritime interests in the South China Sea."
-Mao Ning, Chinese foreign ministry spokesperson
Issue Analysis No. 15
Prof. Bobby M. Tuazon
CenPEG's Director for Policy Studies
October 20, 2026
The Philippine government should bury the idea that a war with China over maritime and territorial disputes in the South China Sea / West Philippine Sea (SCS/WPS) will warrant an “iron-clad” American intervention to defend Manila.
As recent studies in leading American universities show, a U.S. war with China will end either in a stalemate or defeat.
In a probable war scenario, the Philippines will not last even a minor armed conflict. The Philippines ranks sixth in armed strength among nine Southeast Asian military powers, with a Power Index (PwrIndx) score of 0.699. Indonesia leads. (Global Firepower 2026) China is the third most powerful on earth militarily after the U.S. and Russia.
Just the same, the Philippines plays a central role in the U.S. strategy of regional deterrence against China. Manila actively pursues its defense alliance with the U.S. to safeguard its claimed sovereignty in the South China Sea/West Philippine Sea.
But a war between China and the U.S. will involve the use of nuclear weapons – a dangerous option that both countries are trying to control. The reunification of China and its island state of Taiwan, peaceful or otherwise, will compel the U.S. to think twice whether to really defend the Taipei government.
U.S. support is rhetorical if not a mirage. In this light, the Philippines should pursue instead – as mandated by its foreign policy - peaceful, bilateral diplomatic approaches to settle critical issues with China. The diplomatic mechanism that both countries established in 2017 to settle irritants should be put into use.
In resolving territorial disputes with the Philippines, the Beijing government has historically rejected any third-party interference (the U.S., in particular) but is open to negotiate bilaterally. Bilateral deal was agreed upon in a summit between former President Corazon C. Aquino and Chinese core leader Deng Xiaoping in a Beijing summit in 1988. This tact has not pursued by the Philippine government consistently.
Historical error is the premise that China will settle any territorial / maritime dispute with neighboring countries without firing a single shot. True, majority of China's land border disputes were resolved peacefully through pragmatic diplomacy. But several major territorial disagreements resulted in significant military conflicts involving exchanges of fire and human losses.
China has engaged in multiple armed conflicts over territorial and boundary feuds since 1949, including:
a) The Chinese Indian War (1962): Tensions over the Aksai Chin region and the McMahon Line in Arunachal Pradesh escalated into a full-scale, four-week armed confrontation. Chinese and Indian forces engaged in heavy combat, resulting in thousands of casualties. Disagreements remain a core strategic obstacle, leading to fatal, non-firearm physical clashes as recently as 2020 in the Galwan Valley. India, however, is a member-country of BRICS which was initiated by China. (Other members are Brazile, Russia, and South Africa.)
b) The Chinese Soviet Border Conflict (1969): A military clash broke out between the Soviet Union (now specifically the Russian Federation) and China over Zhenbao (珍宝or Damansky) Island and other areas along the Ussuri River, involving heavy artillery, armor, and casualties on both sides. Today, the two countries are locked in friendly relations and maintain a de facto defense alliance along with the DPRK.
c) The Battle of the Paracel Islands (西沙海战 Xīshā Hǎizhàn 1974) and Johnson South Reef Skirmish (赤瓜礁海战 (Chìguā Jiāo Hǎizhàn,1988): China engaged in naval battles with South Vietnam (1974) and a unified Vietnam (1988) over the sovereignty of island features in the South China Sea. Both involved naval gunfire and the loss of military personnel. In 1979, driven partly by border friction and broader geopolitical rivalries, China launched a brief, high-casualty invasion of northern Vietnam.
Today, China is Vietnam’s top priority relationship – “extremely close but complex”. Both countries share deep economic ties, political party (Communist) alignment, and ideological similarities. Vietnam is a member-country of the Belt and Road Initiative (BRI) initiated by China in 2013.
However, substantial friction remains over maritime territorial disputes in the South China Sea.
Conversely, there are also historical lessons from peacefully settled borders. China has resolved 18 of its 23 territorial disputes through compromise and diplomacy, with Beijing bending backward in some cases. The historical record offers distinct lessons from incidents that were settled without a shot being fired.
In resolving disputes, the Beijing government follows “strategic pragmatism”. The paradigm is a problem-solving and decision-making approach that prioritizes immediate practical outcomes, flexibility, and adaptability over and above rigid ideology, dogmatism, or strict adherence to fixed theories. The Chinese leadership has been frequently willing to cede most of the contested land or abandon ancient historical claims if by doing so would achieve a more pressing domestic or international objective – such as ending international isolation, solidifying an alliance, or guaranteeing internal security.
Will the U.S. win in a hypothetical war with China? Studies by major U.S. academic institutions - such as Stanford University and the Harvard Kennedy School’s Belfer Center - show that a conventional war between the two countries over East Asia would result in severe U.S. challenges, potential stalemate, or a costly loss for American forces due to China's regional proximity and anti-access capabilities.
China dedicates all its military resources to a single regional contingency in East Asia, whereas the U.S. military is spread thinly across Europe, the Middle East, and elsewhere: it maintains 800 overseas military base sites across more than 80 countries and territories, managed through various geographic commands and the Pentagon. This concentration makes the Chinese military roughly on par with the U.S. in local western Pacific scenarios.
Research and academic commentary by scholars at Stanford and Australian partners find, on the other hand, that the U.S. military now acknowledges it could lose or struggle to win a localized conventional conflict near China's coastline.The Harvard study concluded that China could deliver a rapid fait accompli (e.g., taking Taiwan) before the U.S. can intervene. The studies also warn that heavy Chinese investments in anti-ship, air-defense, and missile capabilities have turned large parts of the Western Pacific into dangerous "no-go zones," leaving the U.S. at high risk of losing a regional war or facing a bloody, protracted stalemate.
Note that the 1951 Mutual Defense Treaty (MDT) binds the U.S. to assist the Philippines if its armed forces, public vessels, or aircraft are attacked in the Pacific, including the South China Sea. Will it?
The treaty does not guarantee an automatic U.S. retaliation – and going to war remains a subject of intense debate among American military analysts and strategists.
Above all, enforcing the treaty is subject to a U.S. congressional resolution. Politicians would rather subscribe to their constituents’ leanings – most Americans reject war as a policy.
In military terms, an “automatic response” refers to a pre-programmed, reflex-like, or mandated reaction to a specific trigger, threat, or signal - executed without the need for a deliberate or time-consuming decision-making process such as a legislative mandate on a U.S. action. No such requirement was addressed when U.S. forces along with Israel attacked Iran in February this year, where U.S. President Donald Trump threatened to bring Tehran “back to the stone age”!
U.S. leaders may try to calibrate their response to avoid a catastrophic nuclear-armed war with China. To exemplify: During the 2012 Scarborough Shoal standoff, the U.S. did not intervene militarily to expel Chinese vessels, demonstrating that Washington often avoids direct kinetic clashes over disputed shoals and reefs. Is the Philippine government aware of this?
Assessments (including regional evaluations) suggest that U.S. and EDCA-accessible infrastructure in the Philippines still lacks comprehensive wartime support systems - such as continuous fuel, ammunition stockpiles, and robust air defenses - making immediate, massive combat operations a non-option. These are logistical and readiness gaps which the U.S. cannot solve given its logistical shortage.
In addition, a major conflict in Europe, the Middle East, or a concurrent Chinese invasion of Taiwan could strain U.S. military resources, forcing Washington to weigh whether a localized Philippine maritime clash justifies risking a total systemic war. The U.S. military is facing a weapons shortfall. With an economy in decline and citizens’ demand for their government to focus on the domestic economy, waging wars will be unsustainable.
To review, the key elements of U.S.–Philippine deterrence are: 1) Expanded Military Access (EDCA) in nine sites including northern Luzon close to Taiwan and Balabac Island near the South China Sea; Joint Task Force Philippines established by U.S. and Philippine defense officials to coordinate crisis responses and counter Chinese grey-zone coercion; 2) Missile and drone deployments: The U.S. and Philippines have positioned strategic assets - such as High Mobility Artillery Rocket Systems (HIMARS), Medium-Range Capability (Typhon) launchers, and unmanned drones - along the First Island Chain;
3) Shared strategic interests vs. risks: While Washington relies on Philippine geography for "deterrence by denial", domestic critics and regional analysts warn that hosting foreign bases and offensive-capable systems risks making the Philippines a primary target in a wider U.S.–China conflict.
Are there reasons for doubt and uncertainty? China’s flexible approach, includes a) Grey-Zone provocations: China frequently uses coast guard ships, maritime militia, water cannons, and boarding tactics designed to pressure Manila without crossing a clear threshold of a full-scale "armed attack" that automatically triggers a hot war; b) Dual priorities and escalation risks: A direct war with China over remote reefs risks escalating into a catastrophic nuclear-armed superpower conflict, and analysts question whether Washington would risk direct war over minor outposts given competing pressures (such as a potential conflict over Taiwan); and, c) Political volatility: Shifts in U.S. leadership and changing foreign policy priorities raise long-term questions in Manila about the predictability of American security guarantees.
In addition are nuances and constraints: a) Avoidance of direct major war: While bound by treaty, Washington seeks "deterrence by denial" rather than automatically plunging into a full-scale hot war with China, preferring to supply intelligence, maritime support, and joint training to prevent open conflict; and b) Constitutional processes: Under U.S. law, mutual defense commitments require action in accordance with constitutional restrictions rather than a blank-check, instant declaration of war.
Just look: Currently, U.S. President Donald Trump is considering and preparing military options targeting Iran and Iran-backed Houthi rebels in Yemen, following recent Houthi strikes on Saudi civilian and energy infrastructure. Geopolitical analysts concur that Iran is winning the war: After 9 months no prospects are on view for the U.S. achieving its main goals – decapitation, regime change, and so on.
At present, the Philippines’ entanglement with China over maritime and fishing issues lies below the U.S. military priorities. This perception is a subject of intense geopolitical debate, rather than an official military strategy. Ironically, military analysts often view the Philippines as America's most critical military hub in Asia due to its geographic position at the center of the South China Sea, Taiwan, and vital global trade routes.
Given the U.S. constraints, however, will the Philippines still engage China in an armed conflict to defend its sovereignty and territorial claims? Will America leave no stones unturned to defend its vassal state? #
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