The emergence of a regional security framework through the Japan-Philippines comprehensive strategic partnership is positive for Indo-Pacific stability, but its success will remain limited unless Taiwan is recognized as central to the region’s security architecture.
Philippine President Ferdinand Marcos Jr.’s late-May state visit to Japan marked a profound shift in bilateral ties, with the two countries elevating relations to a comprehensive strategic partnership. While the move reflects Tokyo and Manila’s desire to deepen political, economic, and defense ties, it also underscores the emergence of a regional security framework that can respond to the rapidly changing security environment in the Indo-Pacific.
For Taiwan, the deepening strategic partnership between Japan and the Philippines is significant. Situated at the center of the first island chain and facing mounting pressure from China, Taiwan will be directly affected by any shift in the regional balance of power involving Japan and the Philippines.
Equally important is the timing of the Japan-Philippines strategic partnership. The Indo-Pacific region is witnessing intensifying geopolitical competition, driven largely by China’s military and maritime ambitions.
At the same time, US President Donald Trump’s unpredictable foreign policy, attempts to reset ties with China, and pressure on US allies to share the burden of regional security have added further uncertainty to the regional order. These changing political and security conditions have emboldened China to pursue a more assertive posture in the Indo-Pacific.
Beijing has challenged the status quo across the South China Sea, the East China Sea, and the Taiwan Strait. The Philippines faces China’s aggressive behavior around Second Thomas Shoal, while Tokyo confronts Beijing’s threats around the Diaoyutai Islands. Taiwan, meanwhile, remains under Chinese military and political pressure.
In this context, security experts in Japan and the Philippines increasingly argue that any military conflict over Taiwan would have long-term consequences for both countries. Japan’s southwestern islands, situated close to Taiwan, would be exposed during a Taiwan Strait crisis, while the northern Philippines faces similar threats because of its proximity to the Bashi Channel, a major waterway connecting the South China Sea to the Pacific Ocean.
For both countries, Taiwan’s security is therefore inseparable from broader Indo-Pacific stability.
This explains why Tokyo and Manila have indicated that both countries could be drawn into a conflict involving Taiwan. It also underscores why defense and maritime cooperation have become central pillars of the partnership between Japan and the Philippines.
Both sides have taken a slew of measures to boost defense ties, and Marcos’ visit strengthened this trajectory by expanding maritime security, strategic cooperation, and regional resilience.
For Taiwan, an enduring Japan-Philippines strategic partnership is significant for at least two reasons.
First, it enhances regional deterrence by raising the cost of any unilateral effort to change the status quo. More to the point, it sends a strong message to China that any attempt to create instability in the Taiwan Strait would affect more regional states whose security interests are tied to Taiwan’s safety.
Second, the Japan-Philippines partnership reflects a paradigm shift in regional security thinking. For years, Tokyo and Manila pursued policies of strategic ambiguity to protect their economic interests with China while avoiding confrontation over security issues.
Yet Beijing continued its coercive policies toward both countries, leaving little room for meaningful dialogue. Though belatedly, the Philippines under Marcos has moved away from a China-friendly approach and improved ties with Japan and the US.
Japan has also revised its national strategic outlook, increased defense spending, and begun publicly discussing the Taiwan issue.
Taken together, these developments point to a clear conclusion: Taiwan’s security is directly linked to Indo-Pacific stability.
Yet Taiwan also has reason for concern. Tokyo and Manila’s efforts to negotiate maritime boundaries without consulting Taipei risk marginalizing Taiwan’s interests.
The exclusive economic zones claimed by Japan and the Philippines also overlap with Taiwan’s claimed exclusive economic zone in waters east of Taiwan.
Aware of Taipei’s limited ability to object to Tokyo-Manila maritime delimitation talks, Beijing strongly condemned the Japan-Philippines maritime boundary discussions covering waters east of Taiwan, calling them “completely illegal, null and void.”
While China’s criticism is self-serving, the episode nevertheless highlights Taiwan’s vulnerability in regional negotiations from which it remains excluded.
Such developments could leave Taiwan exposed in two ways. First, history suggests that states rarely compromise on territorial sovereignty, making it unlikely that Japan-Philippines maritime negotiations will accommodate Taiwan’s claims.
As a result, Taiwan could face economic and strategic losses. Second, China would likely use the dispute to increase patrols in waters east of Taiwan, gradually asserting greater control over the area.
It is therefore important for Japan and the Philippines to recognize that no regional security framework can succeed while excluding Taiwan, the very actor whose security lies at the center of regional tensions.
At the same time, Taiwan should not be viewed solely through the lens of conflict. It is also a major economic and technological partner whose role in global semiconductor supply chains, maritime trade, and connectivity is indispensable.
The time has come for Indo-Pacific democracies to move beyond narrowly defined notions of territorial sovereignty and take meaningful steps to include Taiwan as a major stakeholder in shaping a free and open regional order.
Taiwan must not be treated as strategically indispensable yet politically marginal.
