Japan Under Trump: Alliance Strains, the Push for Autonomy and Essential Partnerships

CSDS POLICY BRIEF • 25/2025

By Céline Pajon

19.9.2025

Key issues

• Japan is under pressure from the United States (US) on punitive tariffs and demands for increased defence spending. This has sparked deep concern over US credibility and triggered growing domestic calls for greater autonomy.
• Japan is intensifying a long-standing hedging strategy, balancing reliance on the US with enhanced self-defence capabilities and a widening network of strategic partners, while carefully avoiding open confrontation with Washington.
• The concept of strategic autonomy is gaining traction in Japan, especially in economic and diplomatic domains, though full military independence remains constrained by legal, political and logistical limits.

 

Introduction

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.

A similar trend can be observed at the political level. The 20 July 2025 Upper House elections were marked by the LDP’s loss of its majority in the chamber and the rise of populist forces, most notably the Sanseito, which promotes a “Japan First” ideology. US pressure on Japan may have fuelled the emergence of such parties, which capitalise on the democratic malaise and on xenophobic tendencies, while calling for Japan to reclaim full independence, including, for some, the option of nuclear armament. This seems less a realistic, carefully considered proposal than an opportunistic bid for public attention.

This does not signal a fundamental shift in the overall debate. The overwhelming majority of political parties remain supportive of the US alliance, still described in the 2022 National Security Strategy as the cornerstone of Japan’s national security policy. A more vocal debate about the solidity of the relations may be harmful, however, as it exposes the fundamental asymmetrical nature of the alliance. It also means the alliance is more vulnerable to irritants, such as the frequent frictions caused by the US military presence in Okinawa (over 25,000 troops on just 0.6% of Japan’s territory).

Uncertainty over US priorities triggers a serious look at Japan’s future trajectory

Beyond pressing issues like defence spending and tariffs, there is a deeper questioning in Japan over the US commitment to Tokyo’s security depending on its future priorities, as well as concerns over decoupling from the rules-based order. Japan’s future will look very different depending on whether “prioritisers” (those focused on rivalry with China) or “restrainers” (advocating for a more inward-looking approach) gain the upper hand within the Trump administration. The prospect of a US–China G2 or a potential grand bargain (recalling Trump’s direct dealings with Kim Jong-Un at the expense of Japanese interests) fuels fears that Japan could be left out in the cold, facing three nuclear-armed authoritarian states in North Korea, China and Russia. Under Trump’s first term, optimists still hoped the US might eventually correct course; the second Trump administration, however, is cementing an “America First” trajectory that Japan will be forced to confront. For now, Japan has no choice but to adapt to the new reality of a transactional alliance, with no guarantee that its bet will pay off in the long term.

In addition, the Trump administration’s “cognitive dissonance” has fuelled deep unease. While asserting that China remains its strategic priority, the US President has adopted a revisionist stance on territorial sovereignty, as illustrated by his statements on Greenland and Canada. The US vote on 24 February 2025, at the United Nations General Assembly against a resolution condemning Russia’s aggression in Ukraine, symbolised for Tokyo Washington’s abandonment of its traditional role as the guarantor of the liberal international order.

A significant divergence from the US on this rules-based order, highlighted in Japan’s National Security Strategy as one of the country’s three core national interests, would risk a profound decoupling of interests, directly undermining Japan’s strategic priorities. This suggests a clear regression in the global dimension of the alliance, which has been strengthened under former President Biden, while Japan’s efforts will aim at reinforcing the alliance at the regional level to ensure deterrence against threatening neighbours. So far, the fear of abandonment outweighs the blows to national pride. But President Trump has reactivated autonomist trends already visible in Japan as a reaction to the first Trump administration.

A discussion on Japan’s strategic autonomy

Generally, Japan’s officials and experts are shying away from using the term “strategic autonomy”. They see the concept as shaped by the Gaullist legacy of acting independently, maintaining a credible military and nuclear deterrent, and avoiding excessive reliance on the US. In their view, Japan’s overdependence on the US for its defence denies any attempt to distance itself from Washington or act autonomously. In addition, such a posture would send a dangerous signal to China and Russia, implying a weakening of the alliance and inviting them to drive a wedge between allies. Seasoned experts thus recommend that the government ‘not adopt a stance of openly expressing distrust of the US and loudly advocating for “strategic autonomy”’.

In Japan, the concept of “strategic autonomy” is applied primarily in the realm of economic security. The LDP’s December 2020 report, Towards Formulating an Economic Security Strategy, called for the establishment of “Strategic Autonomy” (senryakuteki jiritsusei) and “Strategic Indispensability” (senryakuteki fukaketsusei) to prevent excessive dependence on other countries, while expanding areas where Japan’s expertise and role are essential to the global supply chain.

In other contexts, the simpler term jiritsu (autonomy or self-reliance) is preferred, emphasising the need to reduce overdependence on any actor, including the US – a term more familiar and historically rooted in Japan’s experience as an archipelago deprived of natural resources and dependent on trade for its survival. Pragmatism and the pursuit of autonomy have thus been key features in Japan’s national security.

Defence Minister Gen Nakatani’s reference to the importance of “strategic autonomy” for stable defence ties at the Shangri-La Dialogue last May can likely be explained by the context: his remarks were directed at an audience primarily composed of Southeast Asian countries, longstanding champions of non-alignment and autonomy. Even so, it was an unexpected move from Tokyo and also reflects growing calls for more autonomy.

In the face of abandonment risks and the erosion of the credibility of US deterrence, Japan is pursuing and intensifying its long-standing multi-pronged hedging strategy: strengthening its own defence capabilities, rebalancing roles within a deepened and integrated alliance and establishing a network of US-compatible strategic partners aimed at durably keeping the US in Asia, while opening complementary avenues of cooperation for the archipelago. A third pillar of Japan’s strategy is its proactive support for the rules-based international order. This approach intends to strengthen the current alliance system, but also to guard against its failure or its retrenchment by broadening Japan’s options. This strategy has been recently revived by the work of experts and think tanks. The Sasakawa Peace Foundation (SPF), for example, reflected upon the trajectory of the US ally, reignited the value of the hedging strategy, calling it “Plan A+”, as Plan B – substituting the alliance with cooperation with the United Nations or China – is not an option.

Building its own defence capacities

Addressing the fundamental asymmetry of the alliance (Washington committing to protect Tokyo in the event of an attack – but not vice versa) had already been a concern for the late Prime Minister Abe, whose military normalisation reforms introduced in 2015 enabled Japan to participate, under certain conditions, in collective self-defence and to protect US troops. Kishida’s Zeitenwende policy of doubling the defence budget (to reach 2% of GDP by 2027) and equipping the country with an unprecedented counter-attack capability also aimed at ‘rethinking its excessive dependence on the US for its defence and help itself’. Investments in new capacities and greater integration with the US allow the Japanese Self Defence Forces (JSDF) to hone their skills in terms of amphibious capabilities, cross-services operations and readiness.

This military normalisation, however, also involves a deeper dependence on US forces, as Tokyo remains dependent on its ally’s strike chain (kill chain) for the use of its new long-range strike capabilities, and as Tokyo still very much depends on US defence equipment. Thus, while becoming militarily more capable, Japan is also becoming more closely tied to its American ally. In addition, building up military capabilities still faces significant limitations: budgetary constraints, shortages in JSDF personnel and a substantial gap with the US. Dependence for the foreseeable future, therefore, remains unavoidable, both for technical reasons and due to legal norms and restrictions.

A nuclear option, really? 

The nuclear option – including the possibility of Tokyo acquiring its own nuclear capability to guarantee full independence – has been raised and attracted much more attention than it deserved. While the taboo has now been broken in public debate, there is no serious consideration of pursuing this path. Japan’s priority remains strengthening the credibility of extended deterrence provided by its American ally, including through more regular and better-informed exchanges. Talks on extended deterrence were elevated at the ministerial level in July 2024 and include table-top exercises for strategic signalling. The first guidelines for extended deterrence, including US nuclear protection, were adopted in December 2024.

The boldest experts advocate for an easing of the three non-nuclear principles to allow, in the future, port calls by nuclear-armed submarines or even possible participation by the JSDF in US deterrence missions. Some lawmakers from the LDP have also reportedly been considering this option to bolster deterrence. This could also be considered in the future as a way to facilitate port calls by next-generation AUKUS submarines, thereby strengthening interoperability with allied forces, enhancing Japan’s role in regional deterrence and signalling greater alignment with partners in the Indo-Pacific. For the time being, public opinion remains adverse to Japan developing its own nuclear weapon or hosting US nukes.

An ever-expanding network of strategic partners

Given these limitations regarding the strengthening of military capacity, expanding the range of security partners emerges as the most viable and feasible course of action. Japan’s process of diversifying its strategic partners for more than ten years – first with Australia and India, but also with some Southeast Asian and European countries such as France and the United Kingdom (UK) – serves several, sometimes contradictory, objectives. Most often, it is about anchoring the US in the region by enlisting it in a network of partners with shared interests. It also seeks to increase Japan’s strategic flexibility and hedge against a potential US withdrawal. Thus, Japan could eventually rely on its network of partners to pool resources and develop a more autonomous strategy, decentred from the US.

Today, the Japan-Australia relationship represents the most advanced form of a “quasi-alliance”, as highlighted by the Reciprocal Access Agreement (RAA) that came into force in mid-2023, numerous joint exercises enhancing interoperability and Australia’s recent decision to procure 11 Mogami-class frigates – paving the way for the Japanese defence industry in the international market.

Cooperation with India, though less institutionalised, is also advanced. Japan’s maritime forces have participated in the Indo-US Malabar exercises since 2015, and Prime Minister Modi’s recent visit to Tokyo resulted in a Joint Vision for the Next Decade, in which partners commit to deepening collaboration across security, trade, connectivity, technology and innovation. Tokyo, Washington, Canberra and New Delhi cooperate within the Quad, a key cooperation platform in the Indo-Pacific.

Recently, Japan’s defence commitments have deepened dramatically with the Philippines, with the provision of security assistance, a recent RAA and the first participation of the JSDF in the Balikatan 2025 exercises along with the US.

The Republic of Korea (ROK) is also benefitting from a new dynamic, with the Japan-ROK-US trilateral summit at Camp David in 2023 and the first joint declaration between Tokyo and Seoul in 17 years following the Ishiba–Lee Jae-myung meeting in August 2025.

Today, Japan stands at the centre of a dense interconnected network of partnerships through minilateral – Quad, Squad, Jack, Janzus, Jaukus? – and multilateral frameworks. Once encouraged by the US, the trend to deepen ties between the “spokes” of the alliance system has since created its own momentum, driven in part by China’s increasingly assertive posture in the region. In an essay, Prime Minister Shigeru Ishiba called for the establishment in Asia of a mutual defence treaty similar to that of NATO. While this proposal is unrealistic, the regional security architecture appears to be moving toward a system of integrated deterrence (rather than a collective defence pact) with Japan and the US-Japan alliance as the locomotive of this trend. A major challenge to deepening these security partnerships lies in the need for reforms in key enabling areas, including information security, an integrated intelligence framework and nuclear safety regulations.

Europe as a key partner in Japan’s autonomy

Relations between Japan and European actors (both member states and the EU) are gaining significance. The pursuit of a rules-based international order has been a key pillar cementing closer Japan-EU relations. The first Trump administration accelerated this rapprochement by pushing through the long-sought-after EU-Japan Economic Partnership Agreement (EPA) and Strategic Partnership Agreement (SPA) in 2018. The second Trump administration is also driving deeper cooperation, first, in domains related to economic security, securing supply chains and maintaining stable conditions for free trade. Japan has thus welcomed the announcement of closer ties between the EU and the CPTPP. Second, cooperation between the EU and Japan is deepening in domains that would help mitigate Trump-era challenges to multilateralism, such as energy and climate. Finally, Europe-Japan relations are expanding into new strategic domains such as defence technology, as illustrated by the recent defence pact with the EU and the GCAP deal to jointly develop a next-generation fighter jet with Italy and the UK.

Japanese experts and commentators see Japan and Europe as having unique positions on opposite sides of China and Russia, allowing them to act as complementary strategic partners, reinforcing a rules-based international order and safeguarding global stability. Tsuneo Watanabe from the SPF presents cooperation with Europe as a central dimension of Japan’s “Plan A+” strategy, notably through its partnership with NATO. Japan-NATO collaboration encompasses strengthened responses to cyberattacks and developments in artificial intelligence and is expanding to include ammunition standardisation to help address equipment shortages.

What is more, Nikkei Shimbun commentator Hiroyuki Akita argues that Japan and Europe should define themselves as key partners, with the potential critical mass to uphold the rules-based international order amid destabilising US policies under President Trump. A central idea is to strengthen their collaboration within a “G6” framework to reinforce the effectiveness of the G7, while expanding cooperation with partners such as Australia, New Zealand, the ROK and important European countries.

A quite similar idea is being pushed by Masafumi Ishii, a former Japanese Ambassador to NATO and Indonesia, as he calls for the creation of a group of Permanent Outreach Partners (POP) that would bring together key “Global South” countries alongside like-minded partners, to be invited to G7 meetings. Given France’s efforts to strengthen ties with the “Global South” and engage third countries – particularly as it prepares to chair the 2026 G7 Summit – this suggestion warrants serious consideration.

Conclusion

The alliance with the US, long regarded as the unshakable pillar of Japan’s security, now appears weakened and instrumentalised by President Trump as a mere bargaining lever. The debate on greater autonomy in Japan’s strategic posture is therefore gaining unprecedented momentum. Japan will continue to make concessions to keep the US engaged, while simultaneously pursuing and accelerating efforts to broaden its strategic options, especially in the diplomatic sphere. Achieving greater defence autonomy, however, will remain a longer-term endeavour.

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