What The Upgraded US–Japan Alliance Means For Indo-Pacific Security – Analysis

By Sebastian Maslow

On 28 July 2024, Washington and Tokyo convened their annual Security Consultative Committee, a 2+2 meeting where the allies announced new defence cooperation initiatives and an upgraded military presence in Japan. The most notable change includes upgrading the United States Forces Japan to a joint force headquarters (JFHQ) and expanding its missions and operational responsibilities.

This move is primarily in response to the evolving security environment in the Indo-Pacific, marked by China’s increasing military presence in the East and South China Seas, threats to Taiwan’s autonomy, a bellicose North Korea and Russia’s growing security ties with the Democratic People’s Republic of Korea and People’s Republic of China. Establishing the JFHQ also supports Tokyo’s increasing proactive role in international security.

Geopolitical shifts and increased confidence among alliance managers in Washington regarding Tokyo’s role as a security ally have transformed the US–Japan alliance into a mature military partnership and cemented the alliance as the central hub of the United States’ Indo-Pacific security network.

The shift from a control-based system to an integrated structure is consistent with Washington’s ‘integrated deterrence’ strategy. The reconfiguration of command-and-control structures in Japan enhances day-to-day military coordination and operational cooperation with Japan’s Self-Defense Forces.

This restructuring will transfer operational command over the 55,000 personnel stationed in Japan from United States Indo-Pacific Command in Hawaii to the newly established joint command in Japan. The JFHQ will report to the United States Indo-Pacific Command and assume primary responsibility for coordinating security activities as per the US–Japan Treaty of Mutual Cooperation and Security.

The new headquarters’ commander will remain a three-star general, though the Pentagon has indicated the possibility of dispatching a four-star commander to Japan. This would mirror the US command structure in South Korea and reinforce Washington’s commitment to the alliance.

This transition toward a more mature military alliance was foreshadowed during the April summit between US President Joe Biden and Japanese Prime Minister Fumio Kishida, where they branded the bilateral relationship a ‘global security partnership’ in defence of the liberal international order. The JFHQ also aligns with a new integrated headquarters for Japanese air, ground and maritime forces set to open by March 2025.

Washington’s recent moves reflect increased confidence in Tokyo’s capable national defence posture. Kishida’s administration has further diluted postwar pacifism by committing Japan to closer ties with NATO, increasing defence spending to 2 per cent of GDP and deploying counter-strike capabilities as outlined in the 2022 national security and defence strategies.

Japan also lifted restrictions on license-produced weapons and shipped Mitsubishi-made Patriot PAC-3 missile systems to the United States, replenishing stockpiles depleted by Washington’s military aid to Ukraine. Washington agreed to purchase more PAC-3 missiles from Tokyo at the July meeting.

In early 2024, Tokyo and Washington launched the Defense Industrial Cooperation, Acquisitionand Sustainment framework, initiating a joint production system for advanced air-to-air missiles, which are deployed by the F-35 fighter jets that Japan has purchased in large quantities.

Beyond these efforts, both nations are working to strengthen extended deterrence. Ongoing discussions about the nuclear umbrella aim to counter threats from North Korea, China and Russia. The current integration of alliance functions demonstrates Washington’s commitment to the US–Japan alliance as a cornerstone of its Indo-Pacific strategy, countering China’s rise, securing a self-ruled Taiwan and maintaining the status quo in the South and East China Seas.

Under the second Shinzo Abe administration, Japan implemented its own pivot to Asia and bolstered defence cooperation across Southeast Asia. A modernised US–Japan alliance now places Tokyo at the centre of evolving minilateral security frameworks, including the Quad, US–Japan–South Korea trilateral cooperation, the Trilateral Security Dialogue with Australia and defence technology cooperation under AUKUS’s Pillar II.

Japan has become a vital actor in connecting the spokes of the US-centred security architecture into a networked system of security multilateralism. But this also places Japan on the frontline of potential contingencies involving North Korea or the Taiwan Strait.

Fears of entanglement and calls for greater autonomy from the United States have emerged alongside arguments for deeper integration in US–Japan relations. While concerns persist about Japan becoming a US client state, it is unlikely that the JFHQ and Japan’s Joint Operational Command will be fully integrated into a combined forces command like United States Forces Korea, instead functioning as equal counterparts.

The United States will have a new president by January 2025, amplifying debates over the future of the US–Japan alliance. Meanwhile, Japan’s new prime minister, Shigeru Ishiba, has called for a change in the terms of the ‘asymmetric bilateral’ relationship, pushing for Tokyo be elevated to the status of an equal ally, while transforming the alliance and AUKUS into a NATO-like collective security arrangement in Asia, with Japan as a key member.

Further integration of the alliance’s command and control functions will depend on the commitment of future US and Japanese leaders to allocate the necessary resources for effective alliance management and defence cooperation. A Kamala Harris administration will almost certainly follow through on these commitments, but a second Donald Trump administration threatens to dismantle traditional US alliances in the Indo-Pacific.

• About the author: Sebastian Maslow is Associate Professor at the Institute of Social Science, The University of Tokyo.
• Source: This article was published by East Asia Forum