Executive summary
- As the strategic environment in the Indo-Pacific has deteriorated in recent years, Australia, Japan and the United States (AJUS) have emerged as the most aligned, able and willing countries to pursue a collective regional strategy across the full spectrum of national power. Though initially focused on regional order-building through the Trilateral Strategic Dialogue (TSD) mechanism, defence cooperation has become an increasingly prominent element of the trilateral agenda.
- Such has been the pace and scale of that cooperation that leaders in all three countries increasingly regard one another as “the core” of their shared regional deterrence strategy. This is largely due to an unprecedented convergence in the strategic outlooks of all three countries. Recent Australian, Japanese and US national security documents reflect a shared assessment of the increasingly unfavourable balance of power in the Indo-Pacific, as well as the need for collective action in the service of a strategy of deterrence by denial.
- However, the AJUS trilateral partnership will need to move swiftly from agenda-setting to operational implementation if it is to have its desired impact on the regional strategic balance within a relevant timeframe. Fully delivering on the suite of force posture, exercises, operations, co-development and policy alignment initiatives outlined in successive Trilateral Defence Ministers Meeting statements will require reconciling different national perspectives on when, where and what to prioritise; better aligning policy and regulatory authorities; and managing political disruptions and budgetary constraints.
- This report presents the views of three experienced policy professionals from all three countries on the current state of AJUS, identifying points of consensus between the three countries on the essential next steps for operationalising trilateral defence cooperation, including:
- Creating more robust trilateral information security and intelligence-sharing protocols at all levels, an essential enabler for other forms of cooperation.
- Translating joint exercises into real-world, unscripted operations, particularly for intelligence, surveillance and reconnaissance in the maritime domain, leveraging common manned and unmanned platforms.
- Pursuing trilateral contingency planning for major regional flashpoints, leveraging new command and control arrangements and the forthcoming Trilateral Defence Consultations mechanism.
- Establishing new mechanisms or leveraging existing forums to harmonise different bilateral defence industrial and technology initiatives for the maintenance, production and development of essential capabilities.
The Australia, Japan and US trilateral partnership will need to move swiftly from agenda-setting to operational implementation if it is to have its desired impact on the regional strategic balance within a relevant timeframe.
Introduction
Tom Corben
Research Fellow, Foreign Policy and Defence, United States Studies Centre
Amid a deteriorating strategic environment in the Indo-Pacific, the Australia-Japan-United States (AJUS) trilateral defence partnership has become an increasingly prominent grouping among a number of high-profile security minilaterals in the Indo-Pacific. Though it may lack the same ‘brand power’ of groupings like AUKUS or the Quad, AJUS is arguably the grouping best suited to deliver tangible results when it comes to the balance of military power in the Indo-Pacific. This is because grouping consists of the countries most aligned, able and — importantly — willing to pursue an integrated collective strategy across the full spectrum of national power. Built on over a decade of cooperation and coordination through the foreign ministers’ Trilateral Strategic Dialogue (TSD), this consensus is now beginning to manifest in the defence realm.
Indeed, the recent elevation of defence cooperation in the trilateral context is testament to the unprecedented degree of strategic alignment between the three countries, captured in the emphasis on deterrence and collective action found in each country’s cornerstone strategic documents. The US 2022 National Defense Strategy put the modernisation of America’s alliances with Australia and Japan at the centre of its approach to building a “resilient security architecture” in the Indo-Pacific,1 an approach that looks set to continue under the second Trump administration. Australia’s 2024 National Defence Strategy clearly identified deterrence as the country’s “primary strategic defence objective” in the interests of “maintaining a favourable regional strategic balance and contributing to the collective security of the Indo-Pacific,”2 and included explicit references to trilateral defence cooperation between Australia, Japan and the United States in that context.3 Deterrence and collective action likewise permeated Japan’s 2022 National Defense Strategy, a document which explicitly linked the elevation of the Australia-Japan defence partnership — Tokyo’s “closest cooperative relationship second only to the Japan-U.S. defense cooperation” with supporting the “joint deterrence and response” capabilities of the US-Japan alliance, noting “the prospect of [trilateral] cooperation… in the event of contingencies.”4
In this compendium, three leading experts from Australia, Japan and the United States unpack the current state of trilateral defence cooperation and proscribe priorities for further investigation and implementation.
Unsurprisingly, then, political and policy leaders in all three countries increasingly regard one another as “the core” of their shared regional deterrence strategy.5 But to live up to that billing, the AJUS trilateral partnership will need to move swiftly from agenda-setting to operational implementation. To be sure, there has already been notable progress on a range of cooperative activities detailed in the joint statements from the 2023 and 2024 Trilateral Defence Ministers’ Meetings (TDMM), including: the trilateralisation of here-to bilateral exercises like Talisman Sabre and Keen Edge; expanding trilateral presence missions, including greater intelligence, surveillance, and reconnaissance cooperation; consultations of the development of “strategic capabilities” in areas like integrated air and missile defence and undersea warfare; and greater alignment of “policy and operational objectives… from peacetime to contingency.”6 Yet for these efforts to fully deliver will require overcoming a range of new and enduring obstacles to greater integration, including reconciling different national perspectives on the particulars of how, when and to what extent, certain lines of effort should be implemented; clearly identifying and better aligning relevant policy authorities and touchpoints to better serve trilateral objectives; managing disruptive political developments and budgetary constraints in all three capitals.
In that spirit, the United States Studies Centre, with the support of the Australian Department of Defence, is bringing together leading policy experts and practitioners from across Australia, Japan and the United States to identify the art of the possible across a number of areas for practical trilateral defence cooperation. It is convening a series of five workshops featuring experts and officials from Australia, Japan and the United States focused on these areas, and publishing corresponding reports that will highlight points of consensus or difference between the policy communities across all three countries on priority topics, and will provide consolidated analyses of the opportunities for advancing cooperation in these areas. This compendium is the first in that series, featuring contributions from three leading experts from Australia, Japan and the United States which unpack the current state of trilateral defence cooperation and proscribe priorities for further investigation and implementation.
Time to get real: Advancing US-Japan-Australia operational cooperation
Christopher B. Johnstone
Partner and Chair of the Defense and National Security Practice at The Asia Group
Just a decade ago, trilateral cooperation among Australia, Japan and the United States was long on symbolism and thin on action, with few meaningful areas of cooperation. The first trilateral leaders’ meeting in November 2015, between Prime Minister Tony Abbott, Prime Minister Shinzo Abe, and President Barack Obama, produced a joint statement that “reaffirmed the global reach of their cooperation” — but otherwise did little beyond offering a broad and aspirational list of areas for future work.7 Defence ministers from the three countries began meeting annually at the Shangri La Dialogue in Singapore in the early 2000s, but at first did little more than talk. For staff in the defence ministries of all three countries, those early meetings were an annual headache, as their governments struggled to find concrete deliverables to announce.
Ten years later the picture is entirely different. Security cooperation, in particular, is now concrete, broad, and beneficial to all three countries. At the 15th trilateral defence ministers meeting (TDMM) in November 2024 in Darwin, the ministers announced an agenda that is striking in scope, encompassing exercises and training, information sharing, cooperation in research and development of advanced capabilities, and capacity building with likeminded partners in the region.8 Recent developments on the exercise front are particularly instructive of this growing momentum. Australian personnel participated for the first time last year in the KEEN EDGE US-Japan command post exercise.9 Australian and Japanese F-35 aircraft trained together in each country in 2023, and aircraft from all three countries will join in major exercises this year, including COPE NORTH (US-hosted) BUSHIDO GUARDIAN (Japan-hosted) and PITCH BLACK (Australia-hosted).10 Classified annexes flesh out cooperation in more detail in each of these areas.11
In particular, the revolution in Japanese defence policy and the rapidly deepening bilateral relationship between Japan and Australia have underpinned and enabled this transformation in trilateral cooperation. Tokyo’s expanding security role, and the broad public acceptance in Japan of a more robust defence posture, as demonstrated by the landmark 2022 national security strategy and defence buildup plan,12 have made possible collaboration that would have been unthinkable a few years ago, such as the ministers’ announcement in 2024 that the Self Defense Forces will increase participation in US-Australia force posture initiatives.13 This deepening cooperation rests on a foundation of explicit strategic alignment. In October 2022, Prime Ministers Kishida and Albanese issued a new Joint Declaration on Security Cooperation, in which they “committed to consult each other on contingencies that affect our sovereignty and security interests,” language that deliberately echoed Article III of the ANZUS Treaty.14 Unlike the often politically fraught cooperation among Japan, South Korea, and the United States, today all three legs of the Australia-Japan-US triangle are anchored in strong strategic alignment and supported by deepening practical cooperation.
Advancing trilateral cooperation remains a priority for the United States under President Trump. The Biden administration gave particular emphasis to minilateral cooperation among allies, as part of a larger effort to build a “latticework of strong and mutually reinforcing coalitions” that—while short of a formal multilateral alliance—contribute to deterrence by signalling common resolve.15 The TDMM, along with the State-led trilateral security dialogue (TSD), were central elements of this strategy. Early signs suggest that the Trump administration will sustain this emphasis. In the Joint Statement released after Trump’s meeting with Prime Minister Ishiba Shigeru on 7 February 2025, the leaders announced their intent to “advance multilayered and aligned cooperation among like-minded countries, including Japan-Australia-India-U.S. (Quad), Japan-U.S.-Republic of Korea (ROK), Japan-U.S.-Australia, and Japan-U.S.-Philippines.”16
Despite this remarkable growth in the relationship, areas of concrete, day-to-day operational cooperation among the three defence establishments remain thin and mostly ad hoc. The three countries share deep common interests, but their militaries still do not operate together trilaterally on a routine basis, notwithstanding pledges to translate exercises into “actual operations in the maritime and air domains.”17 Other areas of cooperation—such as defence technology and capability development—remain nascent, even amid periodic debate over whether Japan could someday “join AUKUS”18 and a growing wish list of trilateral co-development categories.19 The thin nature of operational cooperation is perhaps not surprising, given the relatively recent elevation of the trilateral relationship in each country’s strategic outlook, and the reality of the vast geographic distances that separate the three countries.
In that respect, there is much more in the near term that could be done to bring concrete meaning to trilateral security cooperation and to contribute to deterrence and regional stability. Firstly, the three countries could significantly expand military contingency planning, especially related to the Taiwan Strait. Secondly, they could establish a regular pattern of integrated regional intelligence, surveillance, and reconnaissance (ISR) operations. Thirdly, the three countries should collaborate on the co-production of defence equipment, particularly missiles and other munitions. And fourthly, Australia could take a step that would transform defence industrial cooperation among the three countries, by selecting Japan’s bid to build 11 general-purpose frigates for the Royal Australian Navy (RAN). Though ostensibly a bilateral decision, Australia’s selection of Japan as a partner in the project would significantly strengthen defence industry links among the three countries. US defence firms would likely provide weapons systems and other important components to the ships, thereby advancing interoperability among the three navies.
Institutionalise contingency planning
Once a mostly taboo subject in both the US-Japan and US-Australia alliances, the threat of a conflict over Taiwan is now the organising challenge for all three countries. In both classified and unclassified forums, the allies routinely discuss diplomatic, military, and economic responses to a Taiwan contingency, including through tabletop exercises and scenario-based dialogue.20 While trilateral discussions of these topics do take place at the Track 2.0 level, in official channels such dialogue remains largely bilateral and siloed. Given the deep interests at stake for all three governments in a cross-strait conflict, and the high likelihood that the three militaries would in some form all become involved, it is time to establish a formal trilateral contingency planning process, focused on Taiwan and South China Sea scenarios. Such a step would give deeper meaning to the trilateral commitment last November to “consult each other on regional security issues and contingencies.”21 Japan’s planned establishment of a Joint Operations Command (J-JOC) at the Defense Ministry headquarters in Ichigaya in 2025 is the perfect opportunity to do so. Both Australia and the United States will assign liaison officers to the JJOC, and Japan began sending liaison officers to Australia’s HQJOC in November 2024.22 These officers should have an explicit contingency planning function.
Integrate ISR cooperation
Deepening and integrating ISR cooperation would have multiple benefits for all three countries, helping them to maximise effective use of scarce collection assets in a vast theatre and to ensure a common threat picture. The November 2024 TDMM announced a commitment to “grow” trilateral ISR cooperation, including through the assignment of Australian personnel to the Japan-US Bilateral Intelligence Analysis Cell (BIAC) at Yokota Air Base.23 While this is a positive step forward, the three countries should be far more ambitious in deepening ISR cooperation. For example, the three countries should consider establishing a regional ISR hub, centred on integrated and coordinated operations of high altitude, long endurance (HALE) uncrewed aerial vehicles (UAV). All three countries employ interoperable HALE UAV’s: Japan operates the RQ-4 Global Hawk; Australia is acquiring the MQ-4 Triton (a maritime variant of the same platform); and the United States operates both, including some operating out of Japan.24 These aircraft can deploy for more than 30 hours at ranges of greater than 10,000 miles, giving them extraordinary geographic reach that can be used to collect imagery and signals intelligence across the region. Japan’s Global Hawk aircraft in particular are an under-utilised asset, employed for collection missions largely limited to Japanese territory and surrounding waters.25
Deepening and integrating ISR cooperation would have multiple benefits for all three countries, helping them to maximise effective use of scarce collection assets in a vast theatre and to ensure a common threat picture.
Under a regional ISR hub construct, all three countries could make assigned HALE UAV aircraft available for tasking, based on collection requirements and targets that they develop together; collection would be shared among the three partners. A coordinated approach would enable, for example, more persistent and efficient coverage of areas in the South China Sea, or other targets of mutual interest; ISR operations in support of regional disaster relief are another natural area of collaboration. The regional ISR hub could be located either at physical location — like Andersen Air Force base in Guam, or Yokota — or exist virtually, with operations coordinated trilaterally but launched from locations where the aircraft are currently based.
Collaborate on co-production of defence equipment
Defence industry cooperation can make an important contribution to the trilateral security partnership, by supporting interoperability and leveraging the technological strengths of all three countries. Both Japan and Australia have placed a high priority on expanding co-production of defence equipment with the United States, particularly missiles and components. The Biden administration launched the DICAS (Defense Industrial Cooperation, Acquisition, and Sustainment) Forum in 2024, and it supported collaboration under Australia’s Guided Weapons and Explosive Ordnance (GWEO) initiative, each with the intent of supporting local production of mid- and long-range strike and air defence weapons.26 The Trump administration should build on these efforts and work with Australia and Japan to integrate them to the degree possible. Australia and Japan are acquiring many of the same systems, including ship-launched cruise missiles and a variety of air-to-air and air-to-ground weapons. An integrated approach to manufacturing these weapons would allow for more efficient manufacture and exchange of parts, components, and final assembly, to supply all three militaries and ultimately export to third countries.
Integrating elements of DICAS and GWEO would require significant political will — and likely policy change as well. The United States would need to take significant steps to expand information and technology release with its partners, an impediment that has constrained co-production initiatives with both partners, and particularly Japan, a scarcity of high-technology components manufactured only in the United States has limited Japan’s production of Patriot missiles under the DICAS initiative, for example. These are steps that the Trump administration may be more willing to take than its predecessors — provided the benefits to US industry are clear.
To strengthen the business case for co-production, Australia and Japan would likely need to adopt policy that supports exports to other like-minded countries — effectively becoming global production platforms that allow industry to yield economies of scale. The Japanese and Australian markets alone are unlikely to be large enough to warrant establishing new lines of production. Although Japan has significantly loosened constraints on defence exports in recent years, exports of weapons that could be deemed “offensive” continue to be controversial and limited to case-by-case consideration. Australia and Japan could improve the viability of a trilateral arrangement by providing blanket export approval of trilaterally co-produced items up front to an agreed list of partners, included finished weapons.
A critical opportunity: Australia’s frigate competition
No single step would do more to advance trilateral defence industrial cooperation and promote interoperability than Australia’s selection of Japan to build the RAN’s future frigate, to replace the aging ANZAC-class ships. Japan’s Mitsubishi Heavy Industries, which builds the Mogami class frigate for the Maritime Self Defense Force, and Germany’s ThyssenKrupp Marine Systems, which builds the MEKO A-200, are competing to win the bid, which will likely culminate with a decision by Canberra sometime in 2025.27 Selecting the Japanese option would require a leap of faith for Australia: Japan has never exported a major combat system of this scale, and the requirement to build eight of the ships in Australia would test Japan’s ability to transfer technology and build a local supplier base in Australia’s shipbuilding and defence industry. Germany is clearly the safer choice; it built the ANZAC-class and has the benefit of decades of experience working with Australia.
No single step would do more to advance trilateral defence industrial cooperation and promote interoperability than Australia’s selection of Japan to build the RAN’s future frigate, to replace the aging ANZAC-class ships.
But selecting Japan would cement ties between the countries’ defence industries and their navies for years to come. American defence firms would likely supply some of the ship’s weapons systems, making the frigate program truly a trilateral project. Japan will have to demonstrate that the Mogami offers the capabilities Australia needs at a competitive price, and it will have to present a credible plan for technology transfer and local production. But the strategic logic of selecting Japan should factor highly in Canberra’s decision-making. And as Australia expands its shipbuilding capacity as part of the AUKUS initiative and the frigate program, it could be integrated into the DICAS line of effort on naval ship maintenance, repair, and overhaul (MRO).
The Australia-Japan-United States trilateral defence partnership: A Japanese perspective
Professor Tetsuo Kotani28
Professor, Meikai University and Senior Fellow, Japan Institute of International Affairs
Introduction
It’s fair to say that Japan’s approach to regional security challenges in the Indo-Pacific has changed dramatically in recent years. Yet despite occupying the lion’s share of public analysis and commentary, this defence policy revolution has been about more than simply developing Japan’s own capabilities. It has also been about diversifying and modernising Japan’s defence partnerships, too. While the US alliance remains Japan’s priority defence relationship, it has also designated Australia as its most important security partner thereafter. Further, it has also sought to network these relationships through security minilaterals that leverage its alliance with the United States to engage more deeply with partners like Australia, the Philippines and South Korea. These policy trends have come about in response to the deterioration of the regional strategic environment characterised by China’s growing military capabilities, North Korea’s nuclear and missile programs, Russia’s invasion of Ukraine and subsequent activities around Northeast Asia, and questions of US capacity to resource its regional strategy appropriately — all of which amount to what Japan views as an unfavourable shift in the regional power balance.
In that context, pursuing tangible operational defence cooperation through deterrence-focused minilateral security partnerships has become a top priority for Japanese policymakers. In recent years, the Australia-Japan-United States trilateral defence relationship has become one of the most important of those minilaterals for Tokyo, reflected in the grouping’s ambitious agenda and efforts to modernise Japan’s defence relationships with Australia and the United States with the explicit goal of facilitating trilateral defence cooperation. However, there remains much to do for the Australia-Japan-United States defence partnership to have a meaningful impact on the regional strategic balance. The three countries have articulated a robust agenda across the full spectrum of defence cooperation, and have taken early steps to establish more regular joint exercises, explore new command and control arrangements, and to consult on regional strategic challenges, among other pursuits.29 However, translating these efforts into operational cooperation with a real deterrence value will require focusing all three countries’ time and resources on activities that will most immediately contribute to deterring China’s coercion in Japan’s near abroad, while contributing to a more favourable and stable regional balance of power going forward.
The role of the Australia-Japan-US defence partnership in Japan’s strategy
From Japan’s perspective, the Australia-Japan-United States defence partnership fits neatly with two core tenets of Tokyo’s new national security and regional strategies: leveraging its alliance relationship with the United States to deepen other important regional defence relationships, like that with Australia, and to network these relationships in the services of a collective defence strategy; and, in turn, amplifying the effectiveness of Japan’s investments in its own defence capabilities. Japan’s 2022 National Security Strategy identifies the trilateral partnership as among several US-centric minilateral security partnerships that Japan regards as one grouping “among a multilayered network” of relationships essential to “strengthen deterrence” and to achieve “a Free and Open International Order.”30 Among these partners, however, Australia is afforded special status. The 2022 National Defense Strategy states clearly that “[g]iven the prospect of cooperation among Japan, the United States and Australia with Australia,” Japan will seek to “build the closest cooperative relationship second only to the Japan-U.S. defense cooperation,” including through strategic consultations, logistics support and greater information sharing.31
This focus on deterrence-oriented minilaterals is consistent with the elevation of deterrence in Japan’s defence policy settings. This is reflected in the tone of Japan’s 2022 national security documents, the vast increases to defence spending announced in 2022 and subsequently implemented in recent years,32 and the way in which successive prime ministers have spoken about the place and role of defence capabilities in Japan’s national outlook. For instance, Prime Minister Ishiba Shigeru has framed more robust national defence capabilities as “the ultimate guarantee of Japan’s security” amid a shifting power balance, both as an independent means to national ends and as a way of ensuring “the continuing commitment of the United States to the region” in the interests of achieving a favourable regional strategic balance.33 That imperative is also reflected in Japan’s relationship with Australia which has been framed by both countries as intended to support a long-term US regional presence and to facilitate greater trilateral defence cooperation.34 In that respect, from Japan’s perspective, efforts to modernise the US-Japan alliance — whether through new command and control arrangements, defence industrial cooperation, or maritime surveillance operations — will almost certainly benefit, if not require, similar engagement with Australia if Japan is to meet its national defence objectives.
Of course, the election of the second Donald Trump administration has raised questions for many regional analysts over America’s approach to alliances going forward and the fate of regional security minilaterals. While, at the time of writing, there is only limited evidence of how the Trump administration will approach alliances in the Indo-Pacific, early indications suggest that it will persist with existing minilaterals as long as they are deemed good for the America First agenda.35 In that context, the administration’s clear focus on “reestablishing deterrence” in the region and its designation of China as America’s number one national security priority will place the Australia-Japan-US defence partnership in good stead.36 Indeed, from Japan’s perspective, this partnership will likely take on even greater significance given recent political developments in the Republic of Korea (ROK) and the dampening effects that a change of government in Seoul or a prolonged political crisis could have on Japan-ROK-US defence cooperation.37
Towards practical cooperation
While the three countries have articulated an increasingly detailed cooperation agenda at a series of Trilateral Defence Ministers’ Meetings in recent years, there are several areas of particular relevance for Japan given its objectives of generating near-term deterrence effects through bolstering its own capabilities and better networking its top-tier defence partnerships.
Command and control
Firstly, the three countries should explore possibilities for greater cooperation on command-and-control (C2) arrangements. Indeed, it would not be entirely novel for Australian personnel to embed with the appropriate US or US-Japan joint command, considering that the Australian Defence Force is already deeply embedded with the US Indo-Pacific Command, and considering that Australia and Japan are already pursuing reciprocal exchanges of liaison officers between our respective joint headquarters, including in the JSDF’s Joint Operations Command once established.38 This also raises the prospect for Australian personnel to embed with the American joint forces command under US Forces Japan. In either case, this could facilitate greater trilateral operational and contingency planning, as well as provide a firmer basis for coordination of joint operations. Looking further ahead, there is an emerging discussion in the US-Japan context going on over whether to establish a standing combined joint task force to defend the first island chain in the event of a regional contingency. While there’s no clear consensus in Japan over whether this is desirable or feasible, it would make sense for Australia to participate in that arrangement should it come to pass, but this will naturally require steps to be taken now I think coordination among these three countries is very good.
Missile defence: Production, stockpiling and technology
Secondly, the three countries should seek to enhance their cooperation on missile defence, particularly in terms of stockpiling present capabilities and developing the next generation of hypersonic interceptors. In the immediate term, all three countries are seeking to enhance the production and stockpiling of munitions and missile defence capabilities. The United States and Japan are seeking to co-produce medium-ranged air-to-air missiles and PAC-3 missile interceptors and to stockpile these and munitions across American and Japanese military facilities in Japan for joint use.39 Meanwhile, Australia and the United States are also cooperating on weapons production through the Guided Weapons and Explosive Ordnance (GWEO) with a focus on strike weapons, though this will seemingly need to expand to include missile interceptors as Australia looks to develop its own missile defence capabilities.40 Greater coordination of these efforts, including trilateral co-production initiatives and expanding stockpile access to all three partners, will be essential for underwriting effective trilateral operations in the near term.
Australia, Japan and the United States should also consider greater coordination on next-generation missile defence research and development. For instance, the three countries should seek to cooperate through the US-Japan Glide Phase Interceptor (GPI) Cooperative Development (GCD) Project Arrangement established in May 2024 to develop a means of countering hypersonic missiles.41 This would have clear synergies with US-Australia hypersonic strike weapons cooperation, both at the bilateral level and through AUKUS Pillar II with the United Kingdom, under which Japan has recently started participating in uncrewed undersea vehicle activities. The three countries could also cooperate on space and satellite-based tracking measures for missile defence, noting that the United States and Japan have commenced cooperation on the establishment of a satellite constellation to track the hypersonic missiles, and considering Australia’s advantages and interests in space cooperation.
Maintenance, repair and overhaul
Thirdly, the three countries should consider better coordinating their other defence industrial cooperation initiatives, particularly with respect to maintenance, repair and overhaul. While the production and stockpiling of ammunition should be a first-order priority, Japan should consider inviting Australia to participate in the US-Japan Defense Industrial Cooperation, Acquisition, and Sustainment (DICAS) Forum, especially the initiative focused on naval maintenance and shipbuilding. Ensuring that all three countries’ facilities can provide essential MRO support for trilateral naval and air operations will be essential for sustaining joint deterrence and, in the event of a contingency, combat operations. For Japan, this would not only better support a credible and enduring US presence in Northeast Asia but would also provide it with access to additional strategic depth and extra industrial and maintenance capacity were Australian facilities are to be opened to Japanese use. The rationale for such cooperation would only be further boosted were Mitsubishi Heavy Industries to succeed in its bid to supply the Royal Australian Navy with its next generation of frigates, through MRO cooperation should proceed irrespective of the outcome of that process given the three countries’ growing operational agenda and particularly given plans for Japan to rotate more forces through Australian facilities.42
The trilateral plus?
Lastly, the three countries should consider where their cooperative agenda could be expanded to incorporate other regional partners. The Philippines stands out as a particularly promising candidate, given the growing number of maritime cooperative activities that it has conducted with Australia, Japan and the United States.43 The so-called ‘Squad’ should be further enhanced beyond the defence ministers’ meetings and naval exercises to encompass greater air force cooperation, ground forces cooperation, and Coast Guard cooperation to reinforce Manila’s alignment with the trilateral partnership and to send the right signal to Beijing about the credibility of collective deterrence in the region. This would fit neatly with Japan’s recent efforts to supply the Armed Forces of the Philippines with advanced radars and other capabilities and to conclude formal reciprocal access and logistics arrangements to facilitate more regular defence engagements across all services, not just the Navy.44 The success of the Squad could pave the way for engagement with other regional partners, including the Republic of Korea, Singapore and Vietnam.
The three countries should consider where their cooperative agenda could be expanded to incorporate other regional partners. The Philippines stands out as a particularly promising candidate, given the growing number of maritime cooperative activities that it has conducted with Australia, Japan and the United States.
The Australia-Japan-United States trilateral defence partnership: Matching deterrence signalling with credibility
Professor Peter J. Dean
Director Foreign Policy and Defence, United States Studies Centre, University of Sydney
The conceptual foundation of Australia’s regional security is deeply etched in the nation’s foreign and defence policy. Australia’s approach has been founded on the principle of protecting the sovereignty of the state through political and strategic instruments, mainly alliances with great and powerful friends and a military defence capability aimed at deterring conventional threats in the Indo-Pacific. While great and powerful friends — Great Britain and, now, the United States — have been the bedrock of Australian security policy, since the Second World War this has been supplemented by active bilateral relationship-building and multilateral diplomacy in Asia.45
More recently, Australia’s approach to regional diplomacy and strategic partnerships in an increasingly multipolar order has been characterised by a focus on minilateral groupings. Something of a ‘new black’ of Australian regional security policy, these relationships ostensibly provide greater strategic utility compared with the flagging effectiveness of post-Cold War multilateral institutions, given that they are more “task-oriented, exclusive, and more conducive to reaching consensus” and “more agile and adaptable” to evolving circumstances and requirements.46
The ’new black’ of security cooperation has seen Australia enter more than 20 minilateral groupings. But for Canberra, not all minilaterals are created equal. Indeed, the inner circle of Australia’s top-tier minilaterals is comprised of three groupings. Firstly, the Quad relationship has progressed significantly since its revival in 2017 and elevation in 2021 to encompass a wide range of regional order-building initiatives. Secondly, AUKUS has driven defence industrial and technology integration between Australia, the United Kingdom and the United States, with the potential for Japan, the ROK, Canada and New Zealand to participate in future. Thirdly, the Australia-Japan-United States (AJUS) partnership — comprised of Trilateral Strategic Dialogue meetings of foreign ministers and Trilateral Defence Ministers Meetings — has pursued an increasingly ambitious integration agenda, underscored by the 2022 invitation to Japan to integrate into joint US-Australia force posture initiatives in Australia.47
Each of these groups are unique in their own way. AUKUS includes Australia’s current and former major power alliance partners and is squarely focused on developing and delivering asymmetric defence technology advantages over China. The Quad is more focused on regional order-building, includes a major non-alliance partner in India, and has a region-wide scope. AJUS offers something different again. Anchored in mutual US alliance partnerships, it triangulates three maritime powers resident in the north, south and east of the Pacific to form the ‘core’ of each country’s collective regional deterrence strategies.
AJUS in Australia’s regional strategy
The AJUS is increasingly central to all three countries’ strategic policy. For the United States, AJUS fits with a shift from a hub-and-spokes alliance system in Asia to a ‘latticework’ of alliances,48 including by encouraging spoke-to-spoke engagement and coordination. Australia and Japan have embraced such an approach, both in partnership with the United States and more unilaterally. In both Japan and Australia emphasis has increasingly been on their bilateral defence partnership, being regarded as the next most strategically important partnership after their respective alliances with the United States.
Indeed, it is important to note just how far Australia’s strategic partnership with Japan has come in recent years. Since the 2016 Defence White Paper linked United States force posture initiatives “to partners in the Indo-Pacific, including Japan,”49 successive strategic policy documents have increasingly focussed on Japan as central to Australia’s national interests and security objectives amid a deteriorating regional security environment.50 Indeed, the 2024 National Defence Strategy refers to Japan as Australia’s “indispensable partner for achieving regional peace and prosperity,” and notes that the two countries’ Special Strategic Partnership “is underpinned by a strong convergence of values and interests and our growing interoperability, including in a trilateral context with the US.’51 This inclusion of Japan in the NDS section on the US-Australia alliance is a particularly noteworthy structural change from recent documents, which previously treated these relationships as entirely separate discussions, and is reflective of the centrality of trilateral defence cooperation to Australia’s regional strategy.
This was off the back of the 2022 Australia-Japan Joint Declaration on Security Cooperation that engaged a decision for each country to ‘consult each other on contingencies that may affect our sovereignty and regional security interests, and consider measures in response’ — language that mirrors that of the ANZUS Treaty.52
This is also reflective of the growth in stature of the Australia-Japan defence partnership, both in its own right and within the broader context of AJUS since the first of the Trilateral Security Dialogue meetings in 2001. Indeed, advances in bilateral cooperation are largely intended to facilitate trilateral integration. As Tom Corben has noted, Canberra and Tokyo have repeatedly cast bilateral defence cooperation “as mutually reinforcing their respective alliances with Washington and for their trilateral cooperation.”53 This is evidenced through the alignment of each country’s national defence strategies and their focus on deterrence by denial, high-tech capability development and national resilience aimed at maintaining the regional strategic balance.
Practical cooperation
Taken together, the above marks a considerable transformation in the place of Japan and the AJUS with the United States in Australian strategy. Yet much work remains to give this alignment its full operational expression. To be sure, the three countries have increased the number of exercise engagements, sought to deepen their coordination in the Pacific Islands countries and collaboration with ASEAN, and to align their foreign policy approaches to issues in the South China Sea and the Taiwan Strait. Practical defence engagement has focussed on “expanding air-to-air refuelling pairings” between air forces, “unit exchanges and more complex exercises” (i.e. Exercise Talisman Sabre, submarine search and rescue trainings, amphibious operations, etc.) and “enhancing cooperation on strategic capabilities” including on guided weapons, integrated air and missile defence (IAMD), undersea warfare (USW), and intelligence, surveillance and reconnaissance (ISR), all intended to help “to develop a common foundation for optimised and agile operational cooperation.’54
But many of these measures, while important, are largely tactical actions looking for a strategic effect. Greater IAMD, ISR and USW collaboration have the potential to generate greater strategic effects, but there is little public evidence of substantial progress in any of these areas since their announcement in 2022. This means that the deep strategic alignment that has progressed around both the Australia-Japan special strategic partnership and the AJUS has reached a level of maturity that is not being matched by the operational actions required to meet the strategic ambitions that each country has in the region, individually and collectively.
This limited focus on exercises and tactical cooperation has led some Australian scholars to argue the significance of the relationship with Japan and its utility in terms of supporting an enduring US presence in the region have both been over exaggerated,55 and that key developments like the 2022 Reciprocal Access Agreement have simply “given rise to more of the same hyperbole” of a quasi-alliance relationship without the robust operational cooperation to match it.56 Rather than dismissing the relationship out of hand, however, the fundamental question is instead how to seize this current moment of alignment to generate tangible outcomes that address the key defence policy areas of each country: enhancing deterrence and maintaining a favourable regional strategic balance in the face of an increasingly aggressive and capable China.
For Australia, achieving more tangible outcomes will require two related sets of actions: aggressively prioritising the AJUS as a top-tier minilateral within Australian strategic policy, and identifying distinct high-level trilateral operational initiatives that will have impacts on deterrence posture.
The first priority must include a recognition across the Australian system that not all minilaterals are equal. The explosion of the number of minilateral groupings Australia participates in has stretched Australia’s already limited bureaucratic and financial resources, particularly when taken in combination with AUKUS and the Quad. In defence terms, there should be a strong focus on resourcing and preparing dedicated action plans and programs of work on three ‘Tier 1’ groupings: AUKUS, the Quad, and AJUS. Each of these groupings has clear, complementary roles to play in Australia’s regional strategy, and should be prioritised as such. AJUS sits between AUKUS and the Quad in terms of resources, operational focus, and strategic logic. While the latter is evident, its degree of operationalisation does not yet match either the strategic need or the political rhetoric. AJUS needs to assume a more prominent place in Australian thinking, along with a more coherent operational role, and it needs to be resourced to match those ambitions.
Along with Australia’s bilateral alliance with the United States, the AJUS should be the security ‘core’ of Australia’s defence posture in Asia. All three countries are aligned in their strategic ambitions and the advanced nature of the levels of cooperation and trust in the partnership as a vessel for maintaining a balance of power and providing for effective collective deterrence must now be fully embraced across the system. Collective measures are the only means through which an effective balance can be maintained and through which effective deterrence can be achieved — this means that the reality of collective action must match collective rhetoric or the gap between signalling in deterrence and credibility will only widen over time.
This requires the AJUS to deliver more operational measures to provide credible deterrence effects — more exercises and air-to-air refuelling won’t deliver on this alone. IAMD, USW, and plans for ISR can form a foundation for new levels of cooperation, but they need to be accelerated and implemented effectively. IAMD requires functional intelligence, operational, and industrial components, ideally cohered through a public declaration and plan of action. This would be of major benefit to Australia, whose current investment and strategic plans lack a focus on ‘delivering minimum viable capability in the shortest possible time’ for IAMD as required by the 2023 Defence Strategic Review.57 Australia is yet to announce its medium-range missile defence program nor has it identified a pathway for the production of surface-to-air missiles as part of its GWEO plan.58 This is prescient as the 2024 Guided Weapons and Explosive Ordnance plan flagged a reassessment of these areas in the forthcoming 2026 National Defence Strategy and Integrated Investment Plan. IAMD also offers a fruitful area for cooperation on force posture, including through camouflage, concealment and deception, maintenance, sustainment repair, and joint testing as part of a trilateral program of posture work.
The focus on USW should be expanded to include a greater focus on anti-submarine warfare, including operational elements such as a Western Pacific-focused combined anti-submarine warfare operations centre.59 Maritime exercises should have a clear high-end trilateral ASW focus. This is critical as USW and ASW are areas identified where the United States and its allies have a clear asymmetrical military capability advantage. While recent trilateral ISR and MDA activities in the seas around Japan provide encouraging evidence that the three countries are headed in the right direction, it will be important to move beyond simple presence operations to focus on demonstrating high-end deterrent effects and capabilities.
Australia and the United States must balance the risks and rewards of sharing more information with Japan and work towards establishing mechanisms and procedures that will smooth information exchanges and allow for more expedited sharing of intelligence.
The AJUS needs to also advance new areas such as detailed joint contingency planning, discussions that are occurring between Australia and the United States and Japan and the United States, respectively, but not yet at the trilateral level.60 This should occur across three key levels of war: coordination in competition for deterrence; planning for limited regional conflict; and identifying strategic priorities and clarifying roles, responsibilities, posture and capabilities for major war in the region. The development of a new joint HQ in Japan and the standing up of a new US four-star HQ in Japan seemingly provide a new degree of impetus to pursue such collaboration.
These areas of cooperation require capitalising on strategic moments at the operational level, building on the high levels of trust between the three partners, which in turn requires improved intelligence and information-sharing. This is where Japan must enhance its protective security measures and cyber security as a matter of urgency.61 For their part, Australia and the United States must balance the risks and rewards of sharing more information with Japan and work towards establishing mechanisms and procedures that will smooth information exchanges and allow for more expedited sharing of intelligence, particularly in real-time.
Conclusions and recommendations
Tom Corben
Research Fellow, Foreign Policy and Defence, United States Studies Centre
The three expert contributions and trilateral 1.5 workshop conducted in support of this publication suggest that Australia, Japan and the United States are well-placed to translate their ambitious agenda into action. However, these also suggest that not all lines of effort are created equal and that different sorts of activities will pay off over different time horizons depending on whether they are ‘inputs’ (e.g. technology cooperation, joint planning, etc.) or ‘outputs’ (e.g. integrated surveillance operations, etc.) for collective deterrence, and the degree to which the three countries can agree on shared sets of requirements and objectives for each of those lines of effort. The recommendations below capture the main contours of those findings and areas for further investigation.
1. Australia, Japan and the United States are well positioned to translate their unprecedented strategic alignment into tangible operational outcomes, but doing so will require discipline and prioritisation.
The three countries agree on the nature of the regional strategic environment and the imperative of pursuing a coherent collective deterrence strategy in response and have begun to craft an agenda to facilitate that objective. These recent steps have been largely enabled by the rapid advancements in the Australia-Japan defence relationship, an agenda that in many ways has the facilitation of greater trilateral cooperation at its core.62 The primary challenges at hand are to identify a rank order of priorities amongst an increasingly lengthy ‘to-do’ list for the trilateral partnership and to implement those lines of effort at the speed of relevance. Doing so will also require considerable senior-level attention, consistent resource allocation, and political and bureaucratic discipline from all three countries, particularly given the number of other regional minilateral security partnerships that each country is a part of, the global scale of US strategic interests compared to Australia and Japan, and the relative resource and capacity constraints that Canberra and Tokyo face compared with Washington’s largesse. Naturally, this will also require coordinating efforts to modernise the trilateral’s constituent bilateral relationships to ensure that AJUS is well and truly more than the sum of its parts.63
2. The three countries should prioritise the creation of more robust trilateral information security and intelligence-sharing protocols, the essential enabler for all other forms of impactful cooperation.
Workshop participants and project authors agreed that overcoming the remaining barriers to information and intelligence sharing should be a top priority for all three governments. Doing so will be essential to enable the full spectrum of activities on the AJUS defence agenda, including sharing strategic assessments, contingency planning, command and control integration, operational scoping, and defence industrial integration and technology-sharing. Given the already close intelligence relationship between Australia and the United States, much of the onus seems to rest on Japan to pursue reforms to its security of information, security clearance, and cyber security settings to provide the necessary degree of assurance for its AJUS partners, challenges which appear largely technical and capacity-related rather than legal.64 At the same time, Canberra and Washington will need to provide clear guidance and assurances to Tokyo regarding the pathway to greater intelligence integration and will need to account for Japan’s own domestic political and institutional context in pushing for certain kinds of reforms and in weighing the risks and rewards of sharing more, rather than less, with Tokyo. In addition, Australia’s experience with intelligence and information security reforms may offer valuable lessons for Japan in thinking through the scope and scale of its own reform efforts, given that their governance structures are more comparable than with the United States system.65
3. Australia, Japan and the United States should accelerate the translation of joint exercises into real-world, unscripted operations, particularly in the maritime domain.
The trilateralisation of hereto bilateral joint exercises and a growing number of presence operations in the South China Sea are important initial steps. Yet for AJUS to generate credible deterrent effects will require demonstrating a shared capacity to mount unscripted, high-end maritime operations, particularly focused on domains like ASW, IAMD, ISR, and counterstrike. Australia’s invitation to join the US-Japan Bilateral Intelligence Analysis Cell (BIAC) marks an important step, though its precise role or footprint is yet to be fully determined,66 and could provide a useful template or baseline from which to establish more persistent regional ISR operations, including with other partners in appropriate circumstances. Regularising integrated ASW, ISR and MDA operations from Australian, Japanese and US facilities across the region by each country’s maritime patrol and signals intelligence aircraft, such as those already undertaken from Japanese facilities, would sync with similar activities being conducted in the Indian Ocean by Australia, India and the United States.67
4. The three countries should pursue trilateral contingency planning for major regional flashpoints, leveraging new command and control arrangements and the forthcoming Trilateral Defence Consultations mechanism.
Setting expectations and establishing guidelines for how all three countries will respond to a range of regional crises — individually and collectively — will be essential for cohering their practical cooperation around shared operational and strategic objectives. The three countries have committed to establishing “Trilateral Defence Consultations” to align “policy and operational objectives” for their respective defence forces “from peacetime to contingency.”68 Yet experts agree that it will be essential to ensure that these engagements are appropriately scoped to cover a wide range of plausible regional crises across a spectrum of grey-zone, conventional and nuclear scenarios.69 Broaching extended deterrence issues will require closing apparent institutional gaps between the AJUS’s constituent US alliances, whereby Japan and the United States engage in regular, more structured extended deterrence dialogues compared with the more informal unclear arrangements present in the US-Australia context.
5. The three countries should establish a new mechanism, or leverage existing forums, to harmonise their respective bilateral defence industrial and technology initiatives.
Initially, these efforts should focus on naval and aircraft maintenance, repair and overhaul (MRO), and missile and interceptor production. For instance, the three countries could consider how to harmonise MRO efforts under the US-Australia Enhanced Air Cooperation and Enhanced Maritime Cooperation initiatives with the US-Japan DICAS working group on air and naval MRO,70 while Australia and Japan should factor these requirements into their thinking about Mitsubishi Heavy Industries’ bid to supply the Royal Australian Navy with the Mogami-class multi-mission stealth frigate, as well as how to right-size JSDF rotations through Australian facilities. Likewise, the three countries should seek opportunities to harmonise their respective and complementary defence technology development initiatives, such as the US-Australia SCIFiRE hypersonic weapons program and the US-Japan counter-hypersonic glide vehicle program. Beyond providing material support for all three defence forces, these activities will also foster greater interchangeability and encourage a higher degree of standardisation between the capabilities employed by all three defence forces. Indeed, AUKUS Pillar II has been framed in precisely these terms,71 making Japan’s initial participation on uncrewed undersea vehicles (UUVs) an appropriate initial foray considering its own planned and emerging UUV capabilities.72