If Japan navigated quite well the first Trump administration, the second Trump term has proved far more brutal. Even as Tokyo strove to present itself as an indispensable ally for a China-obsessed Washington, it has not escaped the imposition of prohibitive tariffs nor the pressure to increase its defence commitments (some might call it “tough love”). President Trump’s blatant disregard of the rules-based order, long seen as a cornerstone of Japan’s security and prosperity, has caused further shock and consternation in Tokyo.

In the meantime, Japan’s leadership is in disarray. Prime Minister Shigeru Ishiba, in office since September 2024, announced his resignation in September 2025, confirming that Tokyo has entered a new era of political instability after the record-long tenure of the late Shinzo Abe (2012-2020). No potential successor is likely to command both the charisma and legitimacy Abe enjoyed, as the Liberal Democratic Party (LDP) remains in deep crisis. Burdened with weak political leadership, an economy hampered by sluggish consumption and structurally adverse demographics and a worsening security environment, Japan will struggle to defend its interests against an irascible Republican president.

Bruised by an ally whose credibility is eroding, while security threats are mounting, and shocked to see it stray from the fundamental principles of international law by advocating territorial expansion in places like Greenland, Tokyo is left questioning the future of its relationship with the US. The debate on greater autonomy in Japan is gaining unprecedented momentum, with public figures and think tanks openly pondering the possibility of a “Plan B”.

To be clear, this is not the first time Japan has faced difficulties in its relations with its close ally. The traditional dilemma of preventing entrapment and/or abandonment has driven Japan to adopt a multi-pronged strategy to safeguard its interests and expand its space. However, facing unprecedented strains under President Trump’s second term, this CSDS Policy Brief argues that Japan is likely to intensify its hedging strategy vis-à-vis the US: bolstering its defence capabilities, recalibrating the alliance and expanding security partnerships to diversify its diplomatic options, all while fuelling a more vigorous debate over the conditions for greater autonomy. As Europe advances its pursuit of strategic autonomy, it is increasingly considered a crucial partner in Japan’s endeavour to assume a more self-reliant role.

Tariffs and troops: the dual pressure on Japan

Driven by fear of abandonment, Japan’s Prime Minister routinely visits Washington at the start of a new US presidency to seek security reassurances on the ironclad nature of the alliance, Article 5 of the Mutual Security Treaty’s coverage of the Senkaku Islands and America’s full defence commitment – including nuclear extended deterrence.

That box was checked in February 2025, when Ishiba and Trump held their first meeting in a cordial atmosphere, with both leaders ‘affirming their determination to usher in a new golden age in U.S.–Japan relations’. In March, US Secretary of Defense Pete Hegseth confirmed in Tokyo the establishment of a Joint Force Headquarters for the US forces in Japan, intended to coordinate with the newly established Japan’s Joint Operations Command (JJOC), effectively elevating the level of bilateral coordination, integration and readiness.

Yet Japan has been under tough pressure, with Washington demanding greater defence efforts, all while imposing prohibitive and arbitrary tariffs. Already committed since December 2022 to a historic doubling of its defence budget – from 1% to 2% of GDP by 2027 – Japan offered a chilly reception to statements by Elbridge Colby, Under Secretary of Defense for Policy, calling for defence spending to rise to 3.5% of GDP. Tokyo adopted an unusually firm stance, deciding to postpone the planned “2+2” meeting with the US Secretaries of State and Defense.

Japan’s displeasure was also fuelled by the 24% tariffs imposed by Washington in April on Japanese exports to the US – its second-largest market after China – which have hit the automobile sector particularly hard, as it accounts for over 36% of Japan’s exports to the US. After protracted negotiations, which saw Japanese negotiator Ryosei Akazawa travel to Washington ten times, Tokyo was forced on 22 July 2025 to accept a bitter compromise: tariffs set at 15%, coupled with a commitment of $550 billion (€471 billion) in Japanese investments in US projects, entirely at President Trump’s discretion. The publication of related documents on 4 September 2025 clarified the previously unclear terms of the arrangement, while underscoring Japan’s vulnerability to any future arbitrary decision by President Trump to raise tariffs.

Japan’s options for responding to simultaneous US pressures on trade and defence spending are severely constrained by its ageing population, resistance to higher taxes, record-high national debt, sluggish economic growth, and – most critically – a deteriorating security environment that leaves Tokyo little choice but to remain reliant on Washington for its defence. While the pressing issue for Japan is to demonstrate the credibility of its alliance, the Trump administration’s bullying is creating tensions and fuelling mistrust.

Crisis of confidence, not commitment

While Japanese public opinion has long provided strong legitimacy to the alliance, a series of recent polls reveal growing suspicion toward the US and rising interest in greater autonomy. A University of Tokyo survey reveals a stark decline in perceptions of US-Japan relations: only 18% of respondents viewed the relationship as positive in August 2025, down from 45% just one year earlier. Likewise, a March 2025 survey by the progressive Asahi Shimbun found that 77% of respondents doubted Washington would defend Japan in a crisis, while 68% advocated for greater diplomatic independence from the US. These findings echo a June 2025 poll by the conservative Yomiuri Shimbun, in which just 22% of respondents expressed trust in the US. Meanwhile, a Nippon.com survey revealed that 42% of respondents prioritised strengthening Japan’s self-defence capabilities – outpacing support for diversifying alliances (33.7%) or deepening ties with Washington (24.7%).

These polls likely reflect more the acute crisis of confidence in the current US president – a trend shared by many of Washington’s allies and partners – than a genuine rejection of the alliance and the willingness to shoulder the costs of greater autonomy – whether through higher taxes for defence, revising the constitution or even engaging the Self-Defence Forces in combat. While the notion of expanding self-reliance is appealing, turning it into reality still seems a bridge too far. On all three issues, public opinion actually remains adverse, reluctant or at best cautious.

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Read the full article on the website of the CSDS.