June 2025, In the sweltering heat of the South China Sea, a Philippine resupply vessel is rammed by a Chinese Coast Guard ship near Second Thomas Shoal. A 3.5-foot hole is torn through its side, forcing an emergency retreat and injuring multiple crew members. This isn’t a one-off event, it’s the latest in a string of increasingly aggressive Chinese maneuvers aimed at dominating one of the world’s most strategic waterways. The Philippines, once considered a secondary player in the Indo-Pacific, now finds itself squarely in the middle of a geopolitical storm.
For the United States, this growing tension has accelerated a dramatic shift in military strategy. Long reliant on bases in Japan, Guam, and South Korea, the U.S. is now looking south. Under President Ferdinand “Bongbong” Marcos Jr., the Philippines has re-emerged as a vital partner, granting American forces access to nine military sites across the archipelago, including bases on Luzon, just a few hundred miles from Taiwan, and on Palawan, facing directly into the contested waters of the South China Sea. These locations are not symbolic, they’re tactical, positioned to allow rapid response to any regional crisis.
With this renewed alliance, the U.S. is bringing serious hardware to the table. High Mobility Artillery Rocket Systems (HIMARS), Patriot air defense batteries, Stinger missiles, and Marine Ospreys are now regular features on Philippine soil. The 2025 Balikatan military exercises were the largest ever, featuring live-fire drills, island-seizure simulations, and combined operations that left no doubt: the Philippines is now a key node in the American effort to counter China’s expansion.
This renewed partnership is about more than deterrence, it’s about control over a region critical to the global economy. Over $3 trillion in trade passes through the South China Sea each year. Whoever dominates this region controls shipping lanes, resources, and strategic influence across the Indo-Pacific. As China ramps up its presence around Scarborough Shoal, Second Thomas Shoal, and beyond, its goal is clear: push the U.S. out and isolate Taiwan. But the Philippines, once seen as geopolitically peripheral, is now central to stopping that strategy in its tracks.
In the chessboard of Pacific power politics, the Philippines has become the unexpected queen. And the game is just beginning.
Echoes of the Past: Unraveling the South China Sea’s Complex History
The South China Sea dispute isn’t just about modern geopolitics, it’s the product of centuries of overlapping claims and historical ambiguity. Various nations, including China, the Philippines, and Vietnam, trace their sovereignty back to ancient navigation routes and early maritime presence. China frequently refers to dynastic records and old imperial maps to argue for historic rights over these waters. In contrast, the Philippines highlights Spanish-era cartographic evidence, such as the 1734 Velarde map, which clearly includes Scarborough Shoal and parts of the Spratlys within its colonial territory. These competing narratives continue to shape each nation’s legal posture and national identity, forming the historical backbone of today’s volatile dispute.
After World War II, the power vacuum left by Japan’s surrender opened the door to conflicting postwar claims. The 1951 San Francisco Peace Treaty failed to assign clear sovereignty over the Spratly and Paracel Islands. In 1947, the Republic of China drew the now-famous “Eleven-Dash Line,” claiming vast areas of the South China Sea. When the People’s Republic of China replaced the ROC on the mainland, it retained and modified the map into the “Nine-Dash Line.” This ambiguous boundary has since been rejected by international courts but remains central to China’s policy, igniting growing U.S.-China tensions and pulling the region into a dangerous geopolitical game, especially around Taiwan and key shipping lanes.
The discovery of potential oil and gas reserves in the 1970s transformed the region into a resource battleground. Claimant countries began occupying islands and reefs across the Spratly chain, building outposts and asserting control. China rapidly accelerated its activities in the 1990s and 2000s, dredging reefs, constructing airstrips, and militarizing artificial islands with radar systems, missile batteries, and ports. These aggressive moves have drawn strong U.S. responses, including freedom of navigation patrols and expanded defense partnerships. Under President Ferdinand Marcos Jr., the Philippines has become central to America’s strategy to counter China in the Pacific. A new U.S.-Philippines military base agreement has allowed Washington access to critical locations near the Luzon Strait and South China Sea. The deployment of HIMARS, Patriot missiles, Marine Ospreys, and Stingers underscores a sharp shift: the Philippines is now a front-line ally in the effort to contain China’s militarization of one of the world’s most vital maritime routes.
A Patchwork of Claims: Who Wants What (and Why)
The South China Sea is a geopolitical chessboard with overlapping claims from six main players, each driven by historical narratives, legal arguments, and strategic interests. At the center is China (PRC), which asserts “indisputable sovereignty” over nearly the entire sea through its controversial nine-dash line, a claim rooted in vague historical usage but rejected under international law. Beijing sees any opposition as a threat to its territorial integrity and has made its intentions clear through bold, often coercive actions.
The Philippines, under the UNCLOS framework, maintains that features like Scarborough Shoal and parts of the Spratly Islands lie within its Exclusive Economic Zone (EEZ) and are rightfully under its jurisdiction. Backed by a 2016 international arbitral ruling, Manila has stepped up its maritime patrols and revitalized its military relationship with the U.S., making it a frontline state in the effort to counter China in the Pacific. Other claimants include Vietnam, which contests both the Spratlys and Paracels based on historical control; Malaysia and Brunei, which claim parts of the Spratlys within their EEZs; and Taiwan, which still upholds the original eleven-dash line, inherited from the pre-communist Republic of China.
Despite overwhelming legal opposition, China continues to dismiss the 2016 Permanent Court of Arbitration ruling, famously calling it “nothing but a scrap of paper.” Instead, it has pursued a strategy of militarizing artificial islands across the Spratlys, building runways, hangars, and missile systems under the guise of “defensive” measures. These outposts now serve as launchpads for regular patrols by China’s vast Coast Guard and maritime militia, which operate in gray zones, harassing rival vessels, blocking access, and provoking near-collisions without crossing into outright war. This gray-zone dominance enables Beijing to expand its influence while avoiding direct confrontation with the U.S. military.
At the diplomatic level, China wraps its aggressive posture in softer rhetoric, calling for a “Sea of Peace, Friendship, and Cooperation” and proposing joint development with ASEAN nations. However, its real goal is to isolate vocal opponents like the Philippines, particularly as Manila deepens defense ties with America. With its current focus on undermining Philippine credibility within ASEAN, China aims to fracture regional unity and present itself as the only stable power in the South China Sea, on its terms.
The Philippines: From Fading Friend to America’s Forward Edge
The Philippines, once viewed as a fading American partner in the Indo-Pacific, has rapidly reemerged as a strategic linchpin in America’s new Pacific strategy to counter China. Its geography alone makes it indispensable. The Philippine archipelago sprawls across the heart of the South China Sea, straddling one of the world’s busiest global shipping routes. Its northernmost island, Luzon, lies just a few hundred kilometers from Taiwan, making it a critical staging point in any future crisis involving a potential U.S.-Taiwan-China conflict. This geography transforms the Philippines from a passive ally into a forward operating edge of U.S. deterrence in the region.
That wasn’t always the case. Under President Rodrigo Duterte (2016–2022), Manila took a dramatic turn. Seeking closer economic ties with Beijing, Duterte downgraded military cooperation with the U.S., sidelined the Mutual Defense Treaty, and portrayed Washington as unreliable. While China promised investments and infrastructure under its Belt and Road Initiative, its Coast Guard simultaneously ramped up incursions and harassment in Philippine waters. This contradiction, diplomatic smiles, military pressure, left the Philippines vulnerable and disillusioned, as even Duterte’s pivot failed to temper China’s militarization and aggressive posturing.
China’s Potential to Fight Three Nations Simultaneously: The Weight of Giants
The tide turned again with the election of President Ferdinand Marcos Jr. in 2022. Faced with escalating Chinese assertiveness at Second Thomas Shoal and Scarborough Shoal, Marcos Jr. reversed course, strengthening the U.S.-Philippines relationship. He revived joint military drills, expanded the Enhanced Defense Cooperation Agreement (EDCA), and allowed the U.S. access to four new military sites, including bases near Taiwan and the Luzon Strait. This strategic recalibration aligns with the Philippines’ new “Archipelagic Defense Concept”, which shifts focus from internal insurgencies to defending its vast maritime domain. With support from the U.S. military, including deployments of HIMARS, Stingers, and Patriot missiles, the Philippines is positioning itself as the frontline of a regional alliance aimed at deterring further Chinese expansion.
A Timeline of Active Philippine Involvement and Alliance Fortification
The Philippines’ journey from a peripheral player to a pivotal ally in the Indo-Pacific began nearly a century ago, with early constitutional references in 1935 affirming its territorial claims over Scarborough Shoal and the Spratly Islands. But it was China’s occupation of Mischief Reef in 1995 that sent shockwaves through Manila’s defense circles, a moment widely seen as tipping the balance of power in Beijing’s favor. A few years later, in 1999, the Philippines made a defiant move by grounding the BRP Sierra Madre at Second Thomas Shoal, transforming a rusting WWII-era ship into a frontline outpost of sovereignty. That ship, still crewed by Filipino marines, remains a daily flashpoint between the Philippine Navy and the Chinese Coast Guard in 2025.
The standoff at Scarborough Shoal in 2012 marked a turning point that prompted Manila to seek legal recourse. By 2013, the Philippines had filed a historic case against China under UNCLOS, challenging the legitimacy of the nine-dash line. The 2016 ruling by the Permanent Court of Arbitration was a watershed: it declared China’s expansive claims legally baseless and affirmed the Philippines’ rights within its Exclusive Economic Zone (EEZ). But Beijing’s outright rejection of the ruling underscored the limits of legal victories in the face of China’s militarization and its growing gray-zone tactics in the South China Sea.
The real strategic shift came under President Ferdinand Marcos Jr., whose administration began restoring the country’s defense posture and deepening ties with the U.S. military. In February 2023, Manila expanded the Enhanced Defense Cooperation Agreement (EDCA), granting Washington access to four additional bases, some just across the Luzon Strait from Taiwan. This was followed by the largest ever Balikatan exercises in April 2023, with over 17,000 troops engaging in live-fire drills aimed at bolstering deterrence against China’s aggression. A month later, the U.S. and Philippines updated their Bilateral Defense Guidelines, explicitly stating that attacks on either country’s forces, including Coast Guard vessels, in the South China Sea would trigger the Mutual Defense Treaty.
Momentum continued to build throughout 2024 and 2025. Joint maritime patrols began in October 2023. The landmark U.S.-Japan-Philippines trilateral summit in April 2024 and the Reciprocal Access Agreement with Japan that followed signaled a deeper integration of Manila into America’s broader Indo-Pacific alliance network. In April 2025, a SOVFA (Status of Visiting Forces Agreement) with New Zealand was signed, expanding security ties beyond traditional partners. By June 2025, military aid surged, with the U.S. approving $500 million in Foreign Military Financing (FMF) and $336 million earmarked for Philippine defense projects. Now, joint naval drills with the U.S. and Japan are routine, often shadowed by Chinese warships, turning the South China Sea into a live theater of strategic signaling.
The Stakes and the Way Forward
In 2025, the Philippines has emerged as a strategic linchpin in the high-stakes contest for the Indo-Pacific. Its archipelagic geography places it at the heart of vital sea lanes and just a few hundred kilometers from Taiwan, making it indispensable to any credible U.S. military strategy to counter China. Beyond its military value, Manila’s bold defiance of China’s maritime encroachment, legal victory in The Hague, and revival of defense cooperation with the U.S. position it as a symbol of resistance against coercive power in the South China Sea.
Yet, the road ahead is far from easy. The Philippines must balance its deepening U.S. alliance with the realities of economic interdependence with China, its largest trading partner. Domestically, growing U.S. military access under EDCA has sparked concerns about sovereignty and the risks of entanglement in a possible U.S.-China conflict over Taiwan. China’s gray-zone warfare, from maritime harassment to disinformation, continues to test the limits of Manila’s resolve. Managing these internal and external pressures without fracturing political unity or strategic coherence will be a critical challenge for the Marcos Jr. government.
Still, with a reenergized Mutual Defense Treaty, expanded multilateral exercises, and trilateral alignment with Japan and the U.S., the Philippines stands on a firmer strategic foundation than at any point in recent history. As tensions rise across the Pacific, and the specter of conflict looms over both the South China Sea and Taiwan Strait, the Manila-Washington alliance is not just a tactical convenience—it’s a cornerstone for safeguarding the rules-based order and defending a free and open Indo-Pacific.
