Trump-Japan Summit: Alliance Shifts & Future US Ties

The US-Japan alliance remains secure, but growing concerns exist in Asia regarding the firmness of the United States’ commitment to the region. A recent summit between US President Donald Trump and Japanese Prime Minister Sanae Takaichi highlighted these anxieties, avoiding a significant rift but revealing underlying tensions.

Summit Highlights Alliance, Reveals Divergences

The March 19 summit between Trump and Takaichi was notable for what it avoided, occurring amidst the US and Israel’s war against Iran and renewed US pressure on allies to increase their involvement. Takaichi reaffirmed Japan’s position against sending its military to assist US-led efforts in the Persian Gulf, shifting the conversation to areas where Tokyo could demonstrate value within its constitutional and political limits.

A key concern revolves around differing perspectives on Taiwan and managing the challenges posed by China. Both sides reiterated their willingness to cooperate on deterrence and maintain a “free and open” Indo-Pacific strategy, including missile co-development and coordination regarding China and North Korea. However, Trump has expressed disappointment that allies reliant on Gulf energy flows have not provided greater support for US efforts to secure shipping lanes.

Constitutional Constraints and Japan’s Position

Japan faces a delicate situation, as securing shipping lanes is a direct consequence of the US’ actions in Iran, but Tokyo’s options are limited by its constitution. Japan’s 2014 security legislation allows for the use of force in support of an ally only when Japan’s survival is at stake and no other means are available – a threshold not currently met.

Takaichi successfully navigated the summit by declining to join a US-led military effort in the Gulf while convincing Trump that this did not signify disloyalty to the alliance. Japan’s official statement expressed concern over Iran’s actions in the Strait of Hormuz and reiterated opposition to Iran acquiring nuclear weapons, while also focusing on enhancing US-Japan energy security cooperation.

US National Security Strategy and Focus on China

The US National Security Strategy identifies the western hemisphere and managing the China challenge in the Indo-Pacific as its primary focuses, with the US-Japan alliance being central to its strategy. While the situation in Iran is serious, the US and Japan’s primary challenges lie in the Indo-Pacific, particularly concerning China’s growing economic and military power.

Downplaying Taiwan and Sino-Japanese Relations

Japan sought to downplay the issue of Taiwan in its summit readout, given China’s prioritization of the issue and intensified pressure on Japan. In November 2025, Takaichi stated that Japan could face a “survival-threatening situation” in the event of a Taiwan contingency, leading to a deterioration in Sino-Japanese relations.

Washington’s statement reaffirmed its long-standing position on the peaceful resolution of cross-Strait issues, but its apparent insensitivity to Japanese inclinations is notable, given the need for careful alliance management to address the China challenge.

For Japan and many Southeast Asian countries, a significant fear is the potential for the US to abandon its military presence in the region, potentially leading to a “Group of Two” condominium with China and a division of the region into spheres of influence. Trump’s transactional approach and unpredictability have fueled these anxieties.

The US National Security Strategy’s emphasis on rebalancing the economic relationship with China, a departure from previous documents that labeled China a “strategic competitor,” provides Japan with less flexibility, as Tokyo views China’s challenge as primarily strategic, not economic. The war in the Middle East has also diverted US munitions that could have been used in the Indo-Pacific.

While Takaichi may have successfully navigated the recent summit, serious questions remain regarding the solidity of the US’ security commitment in a Taiwan contingency and its overall strategic approach to managing China, casting a long shadow over Japan and Southeast Asia.