The US-Japan-Philippines triad: Part of the US's trilateral security networks around China

Philippine academic Renato Cruz De Castro discusses the prospect of a trilateral Japan-US-Philippines defence pact and the US's building of informal trilateral networks in the Asia Pacific to safeguard its interests against China. However, he notes that there are practical issues to be resolved before a formal agreement can materialise.
Philippine President Ferdinand Marcos Jr. (left) and Japanese Prime Minister Fumio Kishida (right) conclude their joint press remarks after their talks at prime minister's official residence in Tokyo, Japan, 9 February 2023. Kimimasa Mayama/Pool via Reuters)
Philippine President Ferdinand Marcos Jr. (left) and Japanese Prime Minister Fumio Kishida (right) conclude their joint press remarks after their talks at prime minister's official residence in Tokyo, Japan, 9 February 2023. Kimimasa Mayama/Pool via Reuters)

During the tail end of his five-day official visit to Japan, Philippine President Ferdinand Marcos Jr indicated that his administration was reviewing a proposed tripartite security pact with the US and Japan and that this was discussed with Prime Minister Kishida during his visit. This was in the face of the three countries’ increasing tensions with China over security concerns, and that the Philippines could be pulled into a conflict between China and Taiwan.

President Marcos said that fostering alliances with its long-time partners was one of the many other issues raised by the Philippine delegation in Tokyo. He added that such a pact could be “a central element to… providing some sort of stability in the face of all these problems that are seen around us”, adding that it would also help strengthen trilateral ties in “confusing” and “dangerous” situations in the Indo-Pacific and beyond.

However, he emphasised that a proposal for a trilateral security relationship among the three countries was still at the conceptual stage, and there were not yet any details of this tripartite agreement. He implied that the three countries should first sit down and negotiate among themselves and determine what they want to accomplish in establishing and strengthening a trilateral security grouping. He pointed out that this was part of a “continuing process to make more solid partnerships and alliances that we are beginning to put together in our areas”.

A de facto trilateral security network

The idea of a trilateral security partnership between Japan, the US and the Philippines is not new as these countries have been cooperating since the early part of the second decade of the 21st century. China’s maritime expansion in both the East and South China Sea, its construction of artificial island bases, its militarisation of these land features in the South China Sea and its continued grey zone operations against the Philippines and Japan have pushed these countries to strengthen their respective security ties with each other.

In recent years, the US and Japan have accelerated their cooperation with a third regional partner resulting in an informal trilateral network.

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The Philippine Coast Guard's flagship vessel BRP Terersa Magbanua patrols the Spratly Islands in the South China Sea on February 9, 2023. (Philippines Coast Guard)

As noted in the chapter “Asia Pacific” by James J. Przystup and Phillip C. Saunders in the book Charting a Course: Strategic Choices for a New Administration, beginning with the Obama administration in 2011, Washington has supported increased bilateral security cooperation between US allies, most notably between Australia and Japan; Japan and the Philippines; and trilateral cooperation among Japan, Australia and the US among others.

These developments have pushed Japan and the US to focus on maritime security issues in the South China Sea, including maritime capacity building, maritime domain awareness, joint training and exercises, and port calls in Southeast Asia.

In recent years, the US and Japan have accelerated their cooperation with a third regional partner resulting in an informal trilateral network. This form of security collaboration of like-minded allies is seen as an extension of the hub-and-spokes system and a counterpoint to an emergent China in the larger context of an evolving regional security configuration. It is premised on the process designed to strengthen the two bilateral alliances and help build connecting threads between them

Examples of informal trilateral networks include the US-Japan-South Korea trilateral security dialogue that ensures the three countries’ military readiness in the face of unpredictable and belligerent North Korea; the US and Japan’s close relations with Australia to safeguard the security of the Western Pacific; and combined efforts of Japan and the US to boost the Philippines’ naval capabilities relative to the South China Sea dispute. This process also led to the intensification of the Philippine-Japan security partnership. Tokyo has assisted Manila in improving its maritime surveillance capabilities to counter Chinese maritime activities in the South China Sea.

Washington, Tokyo and Manila became aware that Beijing’s invasion and occupation of Taipei would be a substantial boost to China’s strategic position...

Taiwan Strait a catalyst for the tripartite security pact?

On 24 February 2022, Russia launched a full-scale armed invasion of Ukraine. This event brought out into the open an underlying fear among many Southeast Asian states that Russia’s invasion of Ukraine would encourage China to follow suit in the Taiwan Strait, in the South and East China Seas, with the potential of causing collateral damage throughout the region.

Across the Taiwan Strait, China could mount an armed invasion of Taiwan to retake what it deems as a renegade province of China similar to what President Putin did with the invasion of Ukraine. In the South China Sea, borrowing from Russia’s playbook, China might use the pretext of the need to conduct defensive operations against the other claimant states to secure the Spratly Islands and the rest of the South China Sea in the face of apparent US naval aggression and external intervention in the maritime dispute.

Washington, Tokyo and Manila became aware that Beijing’s invasion and occupation of Taipei would be a substantial boost to China’s strategic position as it would enable the People’s Liberation Army’s Navy (PLAN) to impede the US 7th Fleet’s ability to conduct naval and air operations in the Philippine Sea.

They also became aware that China’s control of Taiwan will enable it to base its grouping fleet of attack and ballistic missile submarines on the island, enabling China to threaten Northeast and Southeast Asian shipping lanes as it strengthens Chinese naval presence in the first island chain with its sea-based nuclear forces.

...the US alliances with Japan and the Philippines provide critical access and serve as force multipliers in case of possible armed conflicts in the East and South China Seas and to any potential Taiwan strategic contingencies.

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This handout photo taken on 1 February 2023 and released by Western Mindanao Command (WESTMINCOM) shows US Secretary of Defense Lloyd Austin (right) shaking hands with Westmincom commander Lieutenant General Roy Galido (left) shortly after arriving at the Westmincom headquarters in Zamboanga City, in the southern island of Mindanao. (Handout/Western Mindanao Command/AFP)

As noted in the CSIS report Building a US-Japan-Philippines Triad, this led to the intensification of security cooperation among the three countries as the US alliances with Japan and the Philippines provide critical access and serve as force multipliers in case of possible armed conflicts in the East and South China Seas and to any potential Taiwan strategic contingencies.

As stated in the article “Ramping Up Diplomacy and Defense Cooperation”, in mid-2022, the prospect of heightening tensions between China and Taiwan made it imperative for Tokyo and Washington to align their defence planning for a possible crisis or, in a worst-case scenario, a conflict across the Taiwan Strait.

In early February 2023, the Philippines and the US announced plans to expand the American strategic footprint in the country, with access to four Philippine military bases as the two allies seek to deter China’s increasingly aggressive actions toward Taiwan and the disputed South China Sea.

And as mentioned above, during his recent official visit to Japan, President Marcos and Prime Minister Kishida agreed to strengthen their two countries’ security partnership through strategic reciprocal port calls and aircraft visits, transfer of more defence equipment and technology, continuous cooperation on previously transferred defence equipment, and capacity building.

... the prospect of a formal security agreement among the three countries, however, is not yet on the table.

A formal tripartite security agreement or a trilateral security network?

The Ukraine-Russian War stoked the prospect of China following Russia’s footsteps with a military invasion of Taiwan that could shift the strategic balance in Asia in any number of ways. This led Washington and Tokyo to plan for any possible armed contingency over Taiwan and to strengthen the foundations of their security relations with the Philippines, creating the prospect of a Japan-US-Philippine tripartite security relationship. This relationship might be in the form of either a formal and institutionalised security agreement or it could remain as it is a de facto trilateral security network.

However, one should note that the prospect of a formal security agreement among the three countries, however, is not yet on the table. This is because Tokyo, Washington and Manila need to discuss the practical issues of alliance coordination, shared strategic outlooks, interoperability of their respective armed forces, and more importantly, how their security triangle could be operationalised in the face of a major armed contingency either in the South China Sea or Taiwan.

Furthermore, a possible trilateral security agreement would face legislative scrutiny and even legal challenges from opposition parties and activist groups in their respective civil societies.

In the meantime, the three countries can cooperate through this de facto security network made possible by a strengthened alliance between Tokyo and Washington with both allies strengthening the foundations of their strategic partnerships with Manila.

Related: Closer trilateral US-Japan-Philippines ties to protect security interests against China | Mind the gaps, fill the needs: A strategic outlook for the Philippine-US alliance | Japan’s weapons transfers to Southeast Asia: Opportunities and challenges | Philippine-US cooperation on Whitsun Reef: A 'win' for the Biden team in Southeast Asia?