New Pact Erupts South China Sea Tensions

The Philippines and Japan have taken a significant step in countering China’s assertive maneuvers in the South China Sea by signing a new defense pact.

Story Snapshot

Japan and the Philippines signed the Acquisition and Cross-Servicing Agreement (ACSA) on January 15, 2026.
The pact allows tax-free exchange of logistical supplies between the two nations, enhancing military cooperation.
This agreement is part of broader efforts to counter China’s regional assertiveness.
No ratification is needed from the Philippine Senate, streamlining the process.

Japan-Philippines Defense Pact: A Strategic Counter to China

On January 15, 2026, Japan and the Philippines signed the Acquisition and Cross-Servicing Agreement (ACSA) in Manila. This pivotal agreement facilitates the tax-free exchange of logistical supplies such as fuel and ammunition. It supports joint military exercises, disaster response, and peacekeeping efforts, aiming to fortify defense ties amid escalating tensions with China over the South China Sea.

The signing of the ACSA represents a significant advancement in bilateral defense cooperation, reflecting a strategic countermeasure to China’s growing assertiveness in the region. The agreement enhances the interoperability between the two nations, aligning with trilateral U.S.-Japan-Philippines efforts to maintain a “free and open Indo-Pacific.”

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Historical Context and Strategic Goals

Japan’s defense relationship with the Philippines has evolved since post-WWII normalization in 1956. Recent developments, like the Reciprocal Access Agreement (RAA) signed in 2024, have paved the way for increased military collaboration. The ACSA specifically targets logistical support, differentiating it from the RAA’s focus on troop access, and is set against a backdrop of rising Chinese influence in the South China Sea.

Japan’s motives include countering China’s regional expansion and enhancing its influence within ASEAN through a “quasi-alliance.” The U.S., as a trilateral partner, further encourages this alignment. Both countries benefit from logistical cooperation, which supports joint military exercises and disaster response efforts.

Implications and Future Outlook

The ACSA’s signing marks a substantial leap in Japan-Philippines defense relations. In the short term, it is expected to accelerate joint military drills and enhance disaster response capabilities. In the long term, the agreement institutionalizes a “quasi-alliance” that covers strategy, intelligence, technology, and training. However, while this may deter China’s expansionism, it could also heighten regional tensions.

Japan, Philippines Sign Defense Pacts Amid Surging China Tensions https://t.co/smkAzCoHIS

— AVSEC Pro (@avsec_pro) January 15, 2026

The economic aspects are also significant, with Japan pledging substantial aid for military modernization and infrastructure development in the Philippines. This cooperation not only strengthens military capabilities but also boosts economic and technological ties, further solidifying the alliance’s impact on regional stability.