The Philippines is pursuing strategic diversification by maintaining its alliance with the US while expanding defence partnerships with like-minded countries such as Japan, Australia and India to enhance deterrence and reduce overdependence on a single partner. The approach is primarily driven by China’s expansionist behaviour in the South China Sea.

The Philippines has been transforming its foreign and security policy in recent times amidst a complex security environment in the Indo-Pacific region. While Manila has traditionally relied on the US for external deterrence, it is now actively diversifying its security partnerships. Rising tensions in the South China Sea, coupled with China’s assertive behaviour and grey-zone operations, have prompted the Philippines to widen further its defence and diplomatic engagement beyond its ally, the US.

Manila is building a resilient and multidimensional security architecture by deepening its security cooperation with like-minded countries such as India, Japan and Australia. The diversification is primarily aimed at enhancing defence capabilities, maritime domain awareness and strengthening the country’s position in a complex Indo-Pacific region.

Why Diversification Matters

Located between the South China Sea (SCS) and the Western Pacific Ocean, the Philippines is an archipelagic nation and a strategic chokepoint for China and the United States. The geostrategic location of the Philippines makes it central to the strategic and great-power competition between China and the US. Beijing views the archipelago as crucial for access to the Pacific and for limiting the military presence of its rival powers in its periphery. For the US, the Philippines is a key element of the First Island Chain, whose location helps constrain China’s naval expansion while also offering strategic depth for potential operations in Taiwan’s defence, which is situated less than 200 kms away.[1]

China occupied Mischief Reef in 1995, which is within the Philippines’ claimed Exclusive Economic Zone (EEZ).[2] Relations between China and the Philippines have been shaped by tensions and maritime confrontations in the SCS since 1995. Several Southeast Asian nations have sought to balance their territorial disputes with economic engagement with China; the Philippines has adopted a rules-based approach by challenging Beijing’s claims before the Permanent Court of Arbitration (PCA) in The Hague. The 2016 tribunal ruling favoured the Philippines, further strengthening Manila’s position and garnering international support for upholding international law.[3]

The foreign policy of the former President of the Philippines, Rodrigo Duterte (2016–2022), was more conciliatory towards China, focusing on economic engagement and dialogue. However, since 2022, under President Marcos Jr., foreign policy has been more assertive as he revitalised the country’s alliance with the US and also exposed China’s behaviour in the SCS.

The Philippines has a strong alliance with the US through its 1951 Mutual Defence Treaty (MDT), which is also a cornerstone of the Philippine external defence. This year also marks the 75th anniversary of their defence treaty.[4] The Philippines relies on the US security umbrella for intelligence support, training, military assistance and deterrence against external threats. Agreements between the two countries include the Visiting Forces Agreement (VFA) of 1998 and the Enhanced Defence Cooperation Agreement (EDCA), institutionalising deeper military cooperation. The EDCA, signed in 2014, provides for increased rotational presence of the US forces in the Philippines and seeks to support the Philippines’ military modernisation programme.[5] The EDCA also includes an additional site at the northernmost frontier of the Philippines, close to the Taiwan Strait.

Both countries also signed the General Security of Military Information Agreement (GSOMIA), a framework that facilitates the exchange of classified military information between them.[6] Moreover, joint military exercises between the US and the Philippines have expanded, such as the Balikatan Exercise. These developments underscore that Manila has been deepening its alliance with Washington.

However, the evolving and complex strategic environment has shown that a strong bilateral alliance with the US alone is insufficient to address the security challenges the Philippines faces. China’s assertive actions in the SCS, grey-zone operations by the China Coast Guard, and rampant coercive activities around Philippine-occupied features have highlighted the limitations of relying solely on a single alliance partner. This evolving threat dynamic has prompted Manila to adopt a broader concept of deterrence. The Philippines has sought to build a network of capable security partners that can contribute to maritime security, capacity-building and operational interoperability. Beyond its alliance with the US, the Philippines has expanded its engagement with Indo-Pacific middle powers such as Japan, Australia and India.

Moreover, since launching the three-phase Horizon military modernisation programme in 2013, Manila has been working within that framework to upgrade its defence capabilities. The Philippines is in the third stage of its ‘Horizons’ military modernisation initiative. As part of the programme, the Philippines has set aside US$ 35 billion over the next 10 years.[7] Defence Secretary Gilberto Teodoro Jr. declared the adoption of the third phase of the AFP Modernisation Programme, Revised Horizon (Re-Horizon) 3, on 23 January 2024.

Diversification is also a form of strategic risk management and implies strengthening security ties with other middle powers to reduce the risk of overdependence on a single partner. Several Southeast Asian countries, such as Malaysia and Vietnam, focus on hedging, in which states avoid choosing sides and maintain active neutrality. The Philippines, therefore, pursues a different approach of diversification, especially under the Marcos Jr. administration. Furthermore, expanding defence and security ties with middle-power countries provides Manila with avenues for capability development, maritime cooperation and diplomatic support. Multiple security partnerships also strengthen the Philippines’ position by internationalising the support for a rules-based maritime order.

During Duterte’s Presidency (2016–2022), despite the President’s attempts to downplay the arbitration in favour of a rapprochement with China, the Philippines released its first........

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