Advancing trilateral integrated air and missile defence between Australia, Japan and the United States

Executive summary

• Recent conflicts in Europe and the Middle East have highlighted the changing nature of modern warfare across all domains, particularly with respect to integrated air and missile defence (IAMD). Specifically, the proliferation of low-cost drone and missile capabilities among a range of state and non-state actors has challenged traditional notions of Russia-Ukraine and US-Iran conflicts, which have highlighted both the rapid nature of technological development and the importance of industrial capacity to sustaining and prevailing in this domain.
• These trends have clear implications for Australia, Japan and the United States (AJUS). Indeed, it is no coincidence that the three countries are already advancing their IAMD cooperation, creating a bespoke trilateral data-sharing arrangement and planning to hold a trilateral demonstration activity at Exercise Talisman Sabre 2027. This cooperation is being driven by a shared perception of the threat posed by China’s burgeoning arsenal of short-, medium- and long-range missiles, unmanned aerial vehicles, stealthy submarines and long-range bomber aircraft.
• However, further progress on this agenda is complicated by a global shortage of missile interceptors and precision missiles; the challenge of adapting to rapid technological change; limited industrial capacity and available funding; incremental progress on missile supply chain integration; force structure weakness across the three countries; and moving from bilateral to trilateral approaches to operational planning for regional air defence.
• Therefore, AJUS IAMD will require attention across multiple avenues of the trilateral defence cooperation agenda. This report presents the views of four policy thinkers and professionals from across the three countries on the current state of AJUS IAMD cooperation, identifying points of consensus between the three countries as well as a range of next steps for advancing collaboration. These include:
  • Pursuing greater trilateral operational planning to establish effective divisions of labour between the partners’ short- and long-range air defence capabilities across a range of scenarios.
  • Prioritising greater coordination on defence supply chains for missiles and interceptors, including harmonising and coordinating bilateral initiatives and finding an acceptable division of labour between the partners’ industrial bases.
  • Exploring options for trilateral cooperative programs for new or upgraded missile interceptors and drones to minimise commercial and political barriers to industrial base cooperation.
  • Including industrial and production requirements for IAMD capabilities into trilateral simulation and wargaming activities.

Introduction

Tom Corben
Research Fellow, Foreign Policy and Defence, United States Studies Centre

Recent global conflicts have demonstrated both the centrality of integrated air and missile defence (IAMD) to modern warfare and its changing character. In Ukraine, Kyiv’s survival has depended on its IAMD networks, in particular its ground-based air defence and innovative drone-based missile interception techniques, to protect civil and military infrastructure from long-range Russian attacks.¹ Russian salvos have mixed sophisticated missiles with masses of small and medium drones to complicate Ukrainian defensive efforts and to drain limited stocks of advanced missile interceptors.² Meanwhile, Iran’s inability to sustain IAMD systems has allowed the United States and Israel to establish air superiority and to strike almost at will in two successive attacks in 2025 and 2026³ while US and Israeli air defences performed exceptionally well against Iran’s own missile and drone salvos.⁴ Yet over time, these advantages have not prevented Iranian drones and missiles from inflicting serious damage to American regional force posture and limited air defence assets.⁵ Indeed, American and Israeli forces have quickly burned through high-end interceptors and precision strike weapons at unprecedented rates without having decisively eliminated Iran’s capacity to strike back.⁶

Australian, Japanese and United States personnel salute their national flags during the opening ceremony of Exercise Orient Shield 2025 at Sekiyama Training Area, JapanSource: US Army

Many of these same challenges are also present in the Indo-Pacific. Large Chinese and North Korean stockpiles of long-range missiles and unmanned aerial systems (UAS) have posed serious challenges to US, Australian and Japanese defence posture and planning for many years.⁷ Yet experts and officials increasingly worry that the operational and strategic risks being incurred in Asia as a result of another American military campaign in the Middle East will only exacerbate those challenges.⁸ Apart from providing China with valuable information about US military capabilities and political decision-making, the sophisticated offensive and defensive munitions fired against Iranian targets are the same sorts that would be acutely relevant to a potential US-China conflict — both for US forces and for allies who buy these same systems from Washington.⁹ The second Donald Trump administration has taken some steps to expand missile production rates and to field new low-cost strike and interception capabilities — including through its signature ‘Golden Dome’ initiative — to invert the unfavourable cost curve between expensive American missiles and inexpensive adversarial drones and to replenish depleted stockpiles.¹⁰ Yet these initiatives will take years to deliver new numerical and capability advantages, suggesting that US capacity and innovation will be insufficient to meet the needs of the moment.

Experts and officials increasingly worry that the operational and strategic risks being incurred in Asia as a result of another American military campaign in the Middle East will only exacerbate those challenges.

It is for these reasons that experts have argued that countering Chinese missile and drone capabilities will require a more networked approach to IAMD between the United States and its close allies and partners.¹¹ As the ‘core’ of a strategy of regional collective deterrence, the trilateral defence partnership between Australia, Japan and the United States will be central to those efforts.¹² In fact, IAMD is already central to the trilateral agenda, with the three nations’ defence ministers recently flagging the development of “a networked air and missile defence architecture to counter the growing range of threats throughout the Indo-Pacific.”¹³ Thus far, such a network has included greater information sharing, industrial cooperation, combined exercises and a trilateral live-fire demonstration event as part of Exercise Talisman Sabre 2027.¹⁴ However, these trilateral efforts remain largely in their infancy, in part due to asymmetric progress at the national and bilateral levels. For instance, while IAMD has long been a key mission for the US-Japan alliance, as reflected in the two countries’ respective force structures and exercise agenda, it has only recently become a focus of the Australian Defence Force and the US-Australia alliance. Advancing an effective trilateral IAMD initiative will require deeper collaboration across the full spectrum of defence cooperation: information-sharing, defence industrial and technology development, operational planning, the harmonisation of bilateral agendas behind a trilateral effort.

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 the three countries to identify the art of the possible across a number of areas for practical cooperation. It is convening a series of five workshops featuring experts and officials from Australia, Japan and the United States who are 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 fourth in that series, featuring contributions from three leading experts from Australia, Japan and the United States, which collectively unpack the current state of trilateral air and missile defence cooperation and offer policy options for advancing this critical component of the overall AJUS agenda.

Advancing trilateral air and missile defence cooperation in the Indo-Pacific — a US perspective

Bryan Clark
Senior Fellow and Director, Center for Defense Concepts and Technology, Hudson Institute

Introduction

The US, Australian and Japanese militaries have cooperated in integrated air and missile defence (IAMD) for decades. Mostly, this has consisted of Japanese and Australian forces using US-supplied airborne early warning and control aircraft (AEWC) and air defence systems, which promoted commonality in operational concepts as well as technology.¹⁵ Australian and Japanese militaries pursued US IAMD capabilities largely because they expected to operate in concert with their US counterparts. The Australian Defence Force (ADF) has participated in every major US conflict since the First World War and was integral to 21st-century campaigns in Iraq and Afghanistan. And, consistent with Japan’s defence strategy, the Japan Self-Defense Force’s (JSDF) primary duty is to protect Japan alongside US forces. The allies view common equipment as a path to greater interoperability.

Despite their bilateral cooperation with the US military on IAMD, the ADF and JSDF equip very differently for the mission based on their geography and threat environment. Australia’s remote location reduces the ADF’s need for ground-based air defences (GBAD), as evidenced by its emphasis on air defence ships, fighter aircraft, and short-range GBAD (SRGBAD) systems for overseas missions. The Australian Department of Defence (hereafter, Defence) only recently invested in the US-developed National Air and Missile Defense System (NASAMS) and announced an intent in its new defence strategy to field a medium-range ground-based air defence (MRGBAD) system.¹⁶ In contrast, Japan lacks the geographic depth to create sanctuary for its military forces from local adversaries. The highest-priority mission for both the JSDF and the US-Japan alliance is homeland IAMD. In addition to fielding many current US GBAD and sea-based IAMD capabilities, the Japan Ministry of Defense (JMOD) and US Department of Defense (DoD) co-developed the SM-3 Block IIa surface-to-air missile (SAM) and are collaborating on the Glide Phase Interceptor (GPI) designed to counter hypersonic missiles.

The two US allies also diverge in terms of their operational cooperation with the US military. Japan Air Self-Defense Force (JASDF) units operate US-provided Patriot missile defence systems and routinely exchange personnel and expertise with Japan-based US Army Air Defense Artillery units. Japan Maritime Self-Defense Force (JMSDF) destroyers operate the Aegis Weapon System (AWS) like their US counterparts and practice combined IAMD operations. US-Japan IAMD cooperation will likely grow as the JSDF fields new communication systems like the Cooperative Engagement Capability (CEC) between AWS-equipped ships and E-2D AEWC aircraft. Operational IAMD cooperation is much less developed between US and Australian forces. ADF ground troops shared some SRGBAD systems and tactics with US forces during their Middle East deployments. The Royal Australian Air Force (RAAF) operates common fighters and AEWC aircraft with the US Air Force and Navy and practices defensive counter-air (DCA) operations with US forces during annual or biannual exercises. But these cooperative IAMD engagements are infrequent.

The divergent bilateral technological and tactical connections between US and Australian or Japanese forces reduce opportunities for trilateral cooperation. But the changing operational environment is creating new opportunities and demands for the three militaries to work together.

The divergent bilateral technological and tactical connections between US and Australian or Japanese forces reduce opportunities for trilateral cooperation. But the changing operational environment is creating new opportunities and demands for the three militaries to work together. Over the last two years, the Hudson Institute ran a series of tabletop exercises (TTX) exploring how US, Japanese, and Australian militaries could better counter Chinese aggression, specifically in the event of a potential Chinese blockade of Taiwan. In these scenarios, the US military attempted to restore access while Japanese and Australian militaries attempted to prevent People’s Liberation Army (PLA) forces from passing beyond the First Island Chain comprising Japan, the Philippines and Indonesia. The TTXs were not air defence-centric, but the rapidly expanding PLA air and missile threat made IAMD the most important mission for teams to address. These TTXs identified three IAMD missions where allied needs and technology opportunities intersect and could form a basis for increased collaboration:

• Long-range counter-air capabilities and operations to defeat People’s Liberation Army (PLA) bombers before they can launch strike weapons.
• Short-range air defence (SHORAD) capabilities to address the growing scale of air and missile threats.
• New approaches to IAMD command, control and communications (C3).

Countering the People’s Liberation Army bombers

The PLA’s force design emphasises long-range firepower strike systems that can attack opposing militaries on the ground, in the air, or at sea and slow the introduction of allied forces from outside the theatre. As shown in Figure 1, the PLA could deploy thousands of weapons per day against US allies and bases, mostly from bombers launching cruise missiles or guided glide bombs.¹⁷ Here, the allies’ most pressing air defence problem is that they lack the capacity to shoot down every bomb or cruise missile. To protect their infrastructure, bases, and command and control (C2) nodes, the allies would need to conduct long-range attacks against PLA bombers before they can launch weapons.

Figure 1. PLA strike capacity per day compared with range¹⁸

The Hudson Institute TTXs identified two promising approaches for holding PLA bombers at risk. One approach, which was more relevant to Japan’s geography, used very long-range SAMs (VLR-SAM) to threaten bombers up to 500 nautical miles (nmi; 926 kilometres) from Japan’s coast. The other approach, which was more relevant to Australia, used Collaborative Combat Aircraft (CCAs) to create long-range kill chains that could reach more than 1,000 nmi (1,852 kilometres), to attack bombers beyond their cruise missile launch points. Both concepts are relevant to US forces, which operate from forward bases close to China and more distant locations in the United States or Australia.

Ground-based very long-range surface-to-air missiles

Several militaries field VLR-SAMs, and more are in development. For example, the US SM-6 missile is likely able to engage air targets more than 200 nmi (370 km) away and SM-3 missiles can reach more than 1,500 nmi (2,778 km) away.¹⁹ However, these weapons cost between US$5–15 million each — likely more than the weapons they are engaging — and are in short supply following the recent wars in the Middle East. Instead of using VLR-SAMs only for missile defence, the allies should employ them preferentially against enemy fighters, bombers and AEWC aircraft, which cost ten times more than VLR-SAMs. Figure 2 depicts results using this approach in an air-focused TTX. Teams complemented their attacks on bombers by engaging PLA fighters with uncrewed expendable aircraft such as CCAs or runway-independent Longshot one-way attack (OWA) drones carrying short- or medium-range air-to-air missiles (AAM).

By pushing bombers out past 500 nmi (926 km), ground-based systems like VLR-SAMs can reduce PLA strike effectiveness because bomber-launched missiles will have less fuel for manoeuvres or low-altitude flight that can help them evade air defences.

Long-range kill chains

To impose enduring reductions on PLA strike capacity, the allies need to be capable of shooting down bombers before they can launch missiles, which will require long-range kill chains that can reach more than 1,000 nmi (1,852 km) from the defended coastline. Figure 3 depicts a typical long-range anti-air kill chain used by teams during Australia and Japan-focused TTXs. In this approach, a ground-based over-the-horizon (OTH) radar like the JORN system or a persistent uncrewed sensor such as a high-altitude balloon (HAB) initially detects the bomber.²⁰ It relays the contact to a C2 cell ashore or on an AEWC aircraft, which coordinates the attack.

Figure 3. Depiction of long-range anti-air kill chains used in Hudson Institute wargames

Strike-fighters lack the range to engage bombers more than 1,000 nmi (1852 km) away without refuelling support, which constrains JSDF and ADF counter-air capacity. The JASDF fields four KC-46 Pegasus refuelling tanker aircraft and plans to eventually fly 11 KC-46s.²¹ These could support several combat air patrols 1,000 nmi (1,852 km) from Japan. However, PLA bombers could launch land attack cruise missiles (LACM) from Chinese airspace, which would place vulnerable tankers in range of PLA ground-based SAMs. US forces would face this same challenge. In contrast, while PLA fighters are unlikely to reach the RAAF’s seven KC-30 tankers, they are not sufficient to maintain more than two to three combat air patrols 1,000 nmi (1,852 km) from Australian territory.²²

Figure 3 shows an option to reduce the threat to tankers and demands on aerial refuelling capacity. In this concept, fighters would maintain combat air patrols near their maximum unrefuelled range, using tankers to increase their time on station. From there, fighters could either launch VLR AAMs or deploy CCAs like the MQ-28 Ghost Bat or Longshot. New VLR AAMs like the US AIM-174 can likely engage targets more than 200 nmi (370 km) away, giving strike-fighters an effective reach of about 1,000 nmi (1,852 km).²³ The MQ-28 or Longshot can fly more than 1,000 nmi (1,852 km) after deployment and either hit the bomber themselves or use a medium-range AAM like the AIM-120D to attack, giving the entire kill chain a potential reach of more than 2,000 nmi (3,704 km).²⁴

Long-range kill chains will need a way to provide CCAs and AAMs updates on target location in flight. Allied AEWC aircraft will not be able to track enemy bombers more than 1,000 nmi (1,852 km) away. In the Hudson Institute TTXs, teams used HABs and short take-off and landing MQ-9B UASs launched from amphibious assault ships (LHAs) to provide target updates.²⁵

The kill chain shown in Figure 3 would demand at least two refuelling tankers and a half-dozen fighters. To reduce the number of kill chains needed, allies could use deception and an extended air-defence concept to ‘herd’ enemy bombers into narrow lanes where fighters or CCAs could intercept them. For example, the concept shown in Figure 4 would deploy a small number of real SRGBAD launchers, such as NASAMS, and a larger number of decoy air-defence systems on medium uncrewed surface vessels (MUSVs).

Figure 4. Deception scheme to reduce the air defence capacity needed to stop bombers

Allies would need to buy uncrewed systems and decoys to implement the concept shown in Figure 4. However, these costs are much smaller than buying and crewing a larger air force. When not needed for IAMD, the uncrewed systems can also be stored with minimal maintenance and support, or repurposed to other missions like intelligence, surveillance, and reconnaissance (ISR) or anti-submarine warfare (ASW).²⁶

The United States could help Australian and Japanese militaries maximise the benefits from their investments in uncrewed systems and decoys. The US military is planning to buy hundreds of MUSVs and CCAs and thousands of smaller uncrewed vehicles as part of its efforts to evolve into a larger and more heterogeneous force.²⁷ However, unlike past military buildups, the US DoD intends to buy most of these capabilities via commercial contracting practices and expects industry to do most of the product development and some post-delivery system sustainment. If US, Japanese, and Australian militaries can pursue similar or identical systems, the multi-billion-dollar US investment in its industrial base and new technologies can lower prices, create scale and improve supply chain resilience for all three allies.

Growing local air defence capacity

For more than a decade, the US military argued its pacing threat has been the PLA.²⁸ But since Hamas terrorists launched a large-scale attack on Israeli civilians in October 2023, the Pentagon has once again become operationally focused on the Middle East. Normally, this kind of strategy-action mismatch would be a problem for force planning, but it may have an unintended benefit for US IAMD concept and capability development. By committing US forces to defend Israel, shipping in the Red Sea and Persian Gulf allies, the DoD has gained valuable insights and experience on OWA drones and commercially derived cruise and ballistic missiles that are proliferating worldwide.²⁹

After expending billions of dollars’ worth of SAMs intercepting these threats, the US military developed alternative tactics and is pursuing new technologies that offer higher capacity and lower costs.³⁰ Shorter-range IAMD systems, such as guided cannon-based air defence (CBAD) artillery rounds and short-range SAMs like the Evolved Sea Sparrow Missile (ESSM) or Rolling Airframe Missile (RAM), are smaller than longer-range interceptors. Ships or ground units can carry them in larger numbers, and militaries can buy them in greater quantities.³¹ The US military also renewed its reliance on electronic IAMD capabilities including electronic warfare (EW) systems and directed-energy weapons such as high-power microwave (HPM) and laser systems. These systems offer a nearly limitless magazine but are constrained in range due to dispersion and the need to remain within the target’s line of sight. Electric weapons are especially effective against OWA drones, whose guidance systems depend on GPS or other radiofrequency signals, and use commercial electronics that are susceptible to electromagnetic disruption. US forces used EW against Houthi drones during attacks in the Red Sea and Persian Gulf countries reportedly did the same to Iranian drones and missiles in 2026.³² US troops are also using HPM systems in the Middle East.³³

They should take advantage of the expanding variety of short-range defence systems emerging from conflicts in Ukraine and the Middle East, many of which are commercially derived, self-contained and more affordable than their long-range counterparts.

Though the threat posed by PLA bombers is the most pressing, US, Japanese, and Australian forces will also need increased short-range defensive capacity to protect bases, airfields and critical infrastructure from ballistic missiles, or OWA drones and LACMs from surviving bombers. They should take advantage of the expanding variety of short-range defence systems emerging from conflicts in Ukraine and the Middle East, many of which are commercially derived, self-contained and more affordable than their long-range counterparts. For example:

• The ESSM and Rolling Airframe Missile (RAM) SAMs are built by a consortium of multiple countries and are already used by Australia and Japan.³⁴ The allies should expand production of these SAMs into Australia and Japan to increase capacity and supply chain resilience.
• Technology sharing between the ADF and US military is strong in EW and HPM. This should be expanded to cooperation with Japan, using commercially derived capabilities as a starting point.
• Several companies are building CBAD rounds that can integrate with existing ship and ground force artillery. These guided rounds should have few, if any, export controls, but they could be relatively expensive if built in small quantities. The US DoD should cooperate with Defence and JMOD to identify common CBAD rounds to inform large-scale production runs that can lower prices.

Distributing IAMD C2/C3

Allied IAMD concepts that combine long-range attacks on bombers with short-range defence against missiles and bombs could dramatically increase the number of weapons defeated. However, implementing these approaches will require effective C2 to ensure, for example, that long-range SAMs are not used against inexpensive drones.³⁵ The United States, Australia and Japan should cooperate in IAMD C2 to ensure effective weapon-target pairing. Since the Cold War, the US and allied approach to IAMD C2 incorporated two main elements: AEWC aircraft to manage counter-air operations and C2 nodes such as Aegis-equipped ships or Army Air Defence Artillery headquarters to coordinate missile defence. However, as demonstrated by wars in Ukraine and the Middle East, on-surface ships and C2 nodes are increasingly under threat. Several potential adversaries are fielding OWA drones or missiles designed to find and attack easy-to-detect AEWC radars that will prevent using these aircraft forward in support of long-range kill chains.³⁶

The US, Australian, and Japanese militaries will need alternative approaches to IAMD C2 that are resilient in the face of growing and improving air threats and their ability to preferentially target C2 nodes. Ongoing conflicts in Ukraine and the Middle East are showing that distributed C2 and communications (C3) architectures can persist in a highly contested battlespace. The allies could apply these insights to IAMD by cooperating across four capabilities:

• Low-earth orbit (LEO)-based commercial satellite communications (COMSATCOM) for battle management. Although they cannot transmit data needed for remote engagements, COMSATCOM systems can be as resilient as their military counterparts and are useful for managing weapon-target pairing.³⁷ Within a local IAMD network, such as for a base, allies could use commercially derived line-of-sight (LOS) mesh networks or 5G architectures to allocate targets between engagement systems.
• Uncrewed sensors for target updates and to support decision-making. Long-range kill chains depend on target updates for SAMs or AAMs in transit. If threats prevent moving AEWC aircraft forward, long-endurance UAS such as the MQ-9B or MQ-4C and ground-based radars can provide target-quality data using active radars. They are also increasingly capable of passive targeting, which would enhance their survivability and endurance because they would not need to carry and power a large radar.
• Distributed C2 nodes. The allies will need to move from a few monolithic C2 centres to a more distributed architecture. Although they may not always be able to operate their radars, AEWC aircraft could maintain LOS communications and coordinate IAMD operations across hundreds of miles. Ground-based IAMD C2 could complement AEWC aircraft to provide resilience. To support this distributed architecture, allies should cooperate on interoperable IAMD C2 systems that combine foundational C2 software that executes engagements, such as the US Aegis Weapon System or Integrated Battle Management Command and Control System, with new C2 software suites such as Anduril’s Lattice for battle management and target allocation.
• AI-enabled battle management. The size and heterogeneity of strike salvos demand C2 systems that can rapidly identify and classify threats and determine which defensive systems are appropriate to engage them. Ukrainian and now US IAMD C2 systems are incorporating artificial intelligence (AI) to help operators implement tactics;³⁸ Australian and Japanese militaries should do the same.

Rapidly expanding opportunities

The US, Australian, and Japanese militaries face growing IAMD challenges. The number and diversity of threats continue to grow, from highly capable ballistic and hypersonic missiles to inexpensive and ubiquitous OWA drones. However, the commercialisation and proliferation of militarily relevant technology apply to defence as well. The allies should exploit the expanding availability of sensing, engagement and C2 capabilities to level the playing field.

IAMD among Japan, the United States and Australia: Establishing a cooperative framework for wartime requirements

Admiral (Ret.) Tomohisa Takei
Senior Fellow, Sasakawa Peace Foundation

Introduction: Current status of Japan’s IAMD program

Japan is an island nation, so threats to its territory always come from the sea and air. Keeping North Korea’s ballistic missile threat in mind, Japan introduced a missile defence system in December 2003. For over 20 years, Japan has developed its own air defence system, which includes equipping Aegis destroyers with ballistic missile defence capabilities and introducing the Patriot PAC-3 missile. These trends continue today. The 2022 National Defense Strategy (NDS) clearly stated that there are seven key capabilities that Japan needs to improve, the second of which is integrated air and missile defence (IAMD) capability, after stand-off defence capabilities (i.e. long-range strike).³⁹ The IAMD initiative aims to comprehensively enhance Japan’s air defence capabilities, including those of conventional ballistic missile defence (BMD).

Japan’s IAMD program has two parts: missile defence and counterstrike capabilities. The goal is to prevent airborne attacks by using these capabilities together. First, Japan will use its missile defence system to stop missiles flying over the open ocean and its own airspace. Second, to defend itself and prevent further missile attacks, Japan will use its long-range missile capabilities to conduct an effective counterstrike against the opponent’s territory.⁴⁰ Based on the 2022 National Defense Strategy, Japan has begun to strengthen its IAMD systems, including the construction of two new Aegis system-equipped vessels, upgraded early-warning radars and improvements to missile interceptor systems. Additionally, Japan and the United States signed a joint development agreement in May 2024 for a glide phase interceptor (GPI) to counter hypersonic glide vehicles (HGVs).⁴¹

The world is entering a new era where even terrorist organisations are using weapons like anti-ship ballistic and cruise missiles to challenge the regional order. In the past, these weapons were only used by regular armies, but now they are proliferating globally.

However, the environment surrounding IAMD has changed significantly since the 2022 NDS was issued three years ago. The world is entering a new era where even terrorist organisations are using weapons like anti-ship ballistic and cruise missiles to challenge the regional order. In the past, these weapons were only used by regular armies, but now they are proliferating globally. As technology improves and becomes cheaper, governments and other actors can now use drones and missiles to attack with greater accuracy and longer range. Japan’s 2025 Defense White Paper noted that ballistic missiles are becoming more diverse, complex and sophisticated, while cruise missiles are increasingly accurate.⁴² The paper also noted the stealth and multi-role capabilities of manned and unmanned aircraft,⁴³ which pose further complications for tracking and intercepting IAMD threats.

These developments make it important for Japan to adapt its IAMD program to new environments. Although the 2022 NDS was intended to cover a period of around 10 years, Prime Minister Sanae Takaichi has ordered a review of it well in advance of its expiration in light of rapid changes to Japan’s security environment.⁴⁴ The main agenda items are expected to be equipment and operational challenges, the size of the defence budget and how to secure financial resources, including for IAMD.⁴⁵

The Ukraine War and its implications for trilateral IAMD cooperation

The war in Ukraine has a particular bearing on Japan’s defence planning. Now entering its fourth winter, ground combat between Russia and Ukraine is at a stalemate, and yet the exchange of drones and missiles continues unabated. In both offence and defence, IAMD and strike operations have assumed far greater centrality compared to the early days of war. These developments underscore the necessity of trilateral cooperation between Australia, Japan and the United States in IAMD, lessons from which can be divided into three main categories: (1) IAMD development and innovation competition; (2) levels of war preparedness during peacetime; and (3) preparing for a protracted war of attrition.

1. IAMD development competition

A competition to develop and field unmanned assets is currently underway on the Ukrainian battlefield. As the war in Ukraine drags on, battlefield superiority between Russia and Ukraine continues to fluctuate. At the start of the invasion, Russia’s ground forces overpowered Ukraine’s front lines. However, Ukraine gained the upper hand by employing asymmetric measures. When Russia developed its own countermeasures, Ukraine then employed inexpensive commercial drones for military operations, regaining the superiority. Meanwhile, Russia has established an advanced technology centre — the Rubicon Center for Advanced Unmanned Technologies — to adapt to the rapidly changing battlefield, offsetting areas where Ukraine previously held the advantage.⁴⁶ This back-and-forth competition involves racing to innovate and implement new technologies for both offensive measures or to develop new countermeasures, and the side that dominates this cycle can gain clear advantages over its adversary. The European Union has been actively supporting Ukraine’s defence industry behind the scenes with technical and financial assistance, enabling Ukraine to produce the necessary military equipment more quickly, at lower cost and closer to the battlefield.⁴⁷

This back-and-forth competition involves racing to innovate and implement new technologies for both offensive measures or to develop new countermeasures, and the side that dominates this cycle can gain clear advantages over its adversary.

Regarding drone warfare, there is a competition to develop new equipment as well as new operational concepts. This could be described as a hider-finder competition, where players hide their location while discovering and attacking the enemy. In June 2025, for instance, Ukraine launched a large-scale drone attack against a military base in Siberia, more than 4,300 kilometres from the front lines of war, damaging more than 40 Russian long-range military aircraft.⁴⁸ The remarkable point is that Ukraine, which lags behind Russia in many resource measures, has managed to develop, equip and mass-produce weapons in an extremely short time while fighting. Four factors have contributed to Ukraine’s successes with drone warfare and have played a crucial role in maintaining the resilience of its industrial base: substantial support from the United States and the European Union; a high degree of military-civilian integration; the deployment of highly skilled personnel; and strong government leadership.⁴⁹

2. Level of war preparedness during peacetime

The second issue highlighted by the war in Ukraine is the appropriate level of military preparedness — specifically, the number of weapons and ammunition that should be stockpiled during peacetime. While this challenge is not unique to IAMD, it is particularly relevant for consumables like ammunition. In situations where a protracted war of attrition is anticipated, it is essential to maintain a foundational stockpile during peacetime while simultaneously securing the means to produce or procure additional supplies during wartime.

The developments in the war in Ukraine provide important implications for the level of preparedness that Australia, Japan and the United States should maintain in peacetime. According to reports, Russia launched 3,654 missiles of various types across the whole Ukrainian territory within five months after the invasion.⁵⁰ Ukraine’s land territory is 1.6 times larger than Japan’s. If Japan were to participate in a Taiwan contingency, China possesses an even greater number of missiles than Russia, meaning all of Japan could potentially be subjected to a barrage of various missiles. Assuming all 3,654 missiles are ballistic missiles, attempting to intercept them with a BMD system having a 70% single shot kill probability would require approximately 7,000 interceptor missiles.⁵¹ Based on Japan’s current 24 Patriot battalions and eight Aegis Destroyers,⁵² a simple calculation shows each asset would require about 220 interceptor missiles to meet those requirements.

A Japan Air Self-Defense Force Patriot missile system at Marine Corps Air Station Iwakuni, Japan. Source: US Marine Corps

Possessing this quantity of missiles in peacetime is not impossible for Japan, but some issues need to be resolved. The first issue is the limited capacity of the ammunition magazines. Japan is setting up more magazines, but there are still not enough to store the quantities of interceptors required. The Japanese Government plans to significantly increase ammunition stockpiles to enhance its war-sustaining capabilities. To this end, it intends to construct approximately 130 new ammunition magazines nationwide by 2035. As missiles become larger with increased range, new storage facilities and expansions of existing ones will be necessary.⁵³ Second, unlike artillery shells, missiles cannot be stored long-term: solid fuel degrades over time, and periodic maintenance of electronic components is costly. Thirdly, rapid technological advances are increasing the frequency of necessary missile upgrades. In short, the cost of a single nation possessing large quantities of completed missiles poses a significant financial burden in peacetime. To address these challenges, weapons and ammunition should be stored in a decentralised manner among allied and friendly nations during peacetime. Then, in times of crisis, they should be consolidated and deployed to the nations requiring them. This approach reduces the burden on any single nation and enhances resilience during wartime by diversifying storage locations.

In addition, the war in Ukraine demonstrates the importance of developing sufficient strike capabilities ahead of potential future conflicts. NATO’s moves to strengthen its long-range strike capabilities to deter Russia from attacking Europe could serve as a useful reference for Japan’s counterstrike capability program.⁵⁴ Observing the development of the war in Ukraine, NATO members have begun to recognise the necessity of assuming responsibility for their own conventional security on the continent. A key means of doing so is developing long-range strike capability. NATO members have adopted a policy to reduce dependence on the United States in three core areas: (1) sufficient ammunition stockpiles; (2) missile production capabilities; and (3) kill chain construction capabilities.⁵⁵ Only by overcoming these dependencies can Europe fulfil its responsibility for deterrence and defence through conventional forces. In July 2024, France, Germany, Italy and Poland launched the “European Long-Range Strike Approach,” advancing the development of a European-made ground-launched cruise missile with a range of 1,000 to 2,000 kilometres by the 2030s.⁵⁶

3. Preparing for a protracted war of attrition

The third perspective is the challenge of preparing the defence industrial base for the possibility of a protracted war of attrition. It has been a long time since the war in Ukraine turned into a protracted war of attrition. The war suggests that when nuclear superpowers become involved on opposing sides, both sides prioritise avoiding escalation to nuclear weapons, making protracted conventional warfare more likely to occur.⁵⁷ Applying these lessons to East Asia, it could be surmised that if China attempts to alter the status quo in the Taiwan Strait, and the situation escalates to US military intervention, both the United States and China would likely avoid nuclear war. This would make a Taiwan contingency a protracted war of attrition.

In the event of war, IAMD attrition will increase exponentially. Ukraine’s experience is illustrative. From February 2022 to August 2025, Russia launched more than 9,600 missiles of various types and nearly 14,000 suicide drones towards Ukrainian territory.⁵⁸ The Ukrainian Ministry of Defence says that Ukraine had eliminated 434 aircraft, 4,073 cruise missiles and 93,166 operational-tactical level UAVs as of 23 December 2025.⁵⁹ Ukraine has been able to maintain IAMD production due to the high resilience of its domestic defence industrial base and multilateral cooperation centred on the European Union and the United States. If a Taiwan contingency persists for an extended period, and if Japan is involved, its current industrial base cannot produce enough interceptor missiles to counter the thousands of missiles and tens of thousands of drones that could be fired at it in the same manner as Ukraine has managed to defend itself. To prepare for a contingency in Taiwan, Japan should encourage its domestic defence industry to diversify and become more resilient to maintain the capability to sustain protracted warfare. To diversify its production base, Japan should establish a multinational joint production framework that coordinates with domestic initiatives and strengthens the comprehensive production system for IAMD equipment.

Challenges for trilateral IAMD cooperation

In light of the lessons learned from the war in Ukraine, Australia, Japan and the United States should establish a cooperative framework for IAMD collaboration of defence industrial base that functions even in times of contingencies. The basic directions of cooperation lie in diversifying risks and sharing burdens while strengthening the resilience of a shared defence industrial base. The following areas demonstrate potential for collaboration: (1) research, development and production of IAMD systems; (2) securing sufficient quantities of arms stockpiles through joint storage; and (3) strengthening supply chains through common production bases and geographic dispersion. However, there are challenges that must be addressed to advance this cooperation.

The first challenge concerns accelerating Japan’s defence equipment transfer procedures and defence innovation capacity. Historically, the Japanese Government has imposed strong self-restraint on the overseas transfer of defence equipment. While export controls have gradually eased in recent years as security policy adapts to changing strategic circumstances, including expanding the types of transferable weapons and the range of recipient countries, decision-making still takes an excessive amount of time.⁶⁰ Political decisions on high-priority programs like IAMD cooperation require prioritisation and speed. Furthermore, Japan’s current defence equipment administration struggles to keep up with IAMD development competition over emerging technologies — from research and development to deployment — as seen in the Ukraine war. Efforts to incorporate knowledge from startups into new equipment are only just beginning. If the three countries can collaborate in their respective areas of strength, they have the potential to gain an advantage in development competition.

Cooperation will require common logistics, including the standardisation and commonality of production processes, the skill levels and capacity of defence industries and engineers, inventory procedures and other considerations.

Second is the issue of interoperability within the defence industrial base, which serves as the engine for trilateral defence cooperation. Although the three countries have some experience in joint development at the bilateral level, they have virtually no experience with joint production involving all three countries. Furthermore, they lack a history of dividing labour among production bases and supply chains based on the premise of mutual support in times of emergency. Furthermore, Japan’s defence industry has a long history of primarily serving the Self-Defense Forces as its customer, with limited experience in multilateral cooperation. The defence industries of the three countries operate under different business practices, adapted to their respective domestic systems and regulations. Cooperation will require common logistics, including the standardisation and commonality of production processes, the skill levels and capacity of defence industries and engineers, inventory procedures and other considerations.

Third, shared joint operational plans are indispensable when considering IAMD cooperation in times of contingency. While the three countries have bilateral operational plans based on treaties, at present, they lack any trilateral operational plan. Even without assuming a new alliance, there should be areas where plans can be shared. Scenario-based studies should be conducted to facilitate equipment sharing during specific contingencies, determine the appropriate size of peacetime stockpiles and optimise storage levels across the three countries. The three countries should all consider joint logistics requirements to overcome the tyranny of distance of the Pacific Ocean, particularly for maritime transport through contested seas during wartime, to underwrite resilient IAMD cooperation in a conflict scenario.

Trilateral Integrated Air and Missile Defence: The logic and limitations of Australian engagement

Peter J. Dean
Professor of Strategic Studies, Australian National University

Introduction

This paper provides an overview of the logic, constraints and prospective pathways for trilateral Australia–Japan–United States (AJUS) cooperation on Integrated Air and Missile Defence (IAMD) from an Australian perspective. It argues that, despite positive efforts in the 2026 National Defence Strategy, Australia’s current IAMD posture remains heavily weighted toward sensors, command-and-control, and air and maritime platforms, while ground-based air defence and active missile defence depth remain comparatively limited. It also assesses that the range and number of missile-defence platforms available to the Australian Defence Force (ADF) are very limited. This is both a problem for national defence and trilateral cooperation, but also an opportunity for Australia to enhance its self-reliance in IAMD through AJUS. The paper assesses capability and investment settings, outlines practical barriers to deeper integration, and identifies some near- to medium-term opportunities for cooperation spanning force design, industrial capacity and enabling technologies.

Strategic context and the emerging requirement for homeland defence

The foundation of the Australia–Japan–United States (AJUS) strategic partnership remains solid. Despite the turmoil of the second Trump administration, the strategic drivers of the Indo-Pacific and the mutual regional threat assessments of all three countries remain broadly aligned. The issue of modernising the US alliance system and expanding it through cooperation in minilateral groups like AJUS is still overwhelmingly driven by a mutually reinforcing effort to manage China’s rise, to deter the People’s Republic of China (PRC) from using force to achieve its political objectives and to ensure a regional strategic balance.⁶¹

However, the national landscape in the Indo-Pacific is changing, US policy priorities are shifting and the character of war is evolving, with contemporary conflicts demonstrating that the importance of IAMD has never been greater. For example, the ability to field a robust IAMD system has been a critical foundation for the tactical and operational success of the United States and Israel in their recent conflicts with Iran.⁶² In addition, the vulnerability of traditional air defences to new forms of attack, driven by the expanded use of uncrewed systems, has been evident across other recent conflicts such as the war between Russia and Ukraine and the recent India-Pakistan conflict.⁶³

A key lesson from recent conflicts has been the need for ‘full-spectrum air defence’. Full-spectrum air defences need to be able to address threats from Uncrewed Aerial Systems (UASs) as well as cruise missiles and ballistic missiles, which may be used in isolation or in combination, or to exert political pressure on key economic or political areas of a state. Central to the success of modern IAMD systems has been their ability not only to provide full-spectrum defence but also to integrate sensors and effectors from multiple manufacturers and countries, improving performance through the interchangeability of data, systems and information.

The massive expansion of long-range missile systems by the PRC, including hypersonic, cruise and ballistic missile systems, means that once sanctuary areas on the Australian mainland are now vulnerable to attack.

Australia’s strategic context is also shifting. It is no longer able to operate under an umbrella of US air control, or even potentially US air superiority, in the Indo-Pacific.⁶⁴ The survivability of ADF systems, platforms, infrastructure and deployed units in a high-end contingency has been significantly eroded. The massive expansion of long-range missile systems by the PRC, including hypersonic, cruise and ballistic missile systems, means that once sanctuary areas on the Australian mainland are now vulnerable to attack.⁶⁵ That has ramifications not only for Australia, but also for its military partners. The most recent Chief of the Defence Force, Admiral David Johnston, has often noted the requirement for Australia to conduct operations from the continent, including homeland defence, in partnership with allies in the event of a major contingency.⁶⁶ Furthermore, Australia is pursuing Enhanced Force Posture initiatives with the United States and a growing Force Posture Agreement with Japan,⁶⁷ which will necessitate a shift in Australian — and collective — IAMD preparedness.

The core of Australian IAMD structure: AIR 6500

AIR 6500 is Australia’s principal modernisation program for IAMD and has been in place since at least 2016.⁶⁸ It initially comprises three elements: a Joint Air Battlespace Management project, a medium-range ground-based air defence program and an advanced missile defence program. The first component has dominated ADF investment in this area.⁶⁹ The latter two components were originally standalone projects, AIR6502 and AIR6503, and while these have now been consolidated into AIR6500,⁷⁰ they receive minimal funding in comparison to the former.

The long range Derringer trailer-mounted Expeditionary Launch System is visited by a group of VIPs during Exercise Taipan Strike 2026 activities held at the Woomera Test Range in South Australia.Source: Australian Department of Defence

Current ADF IAMD capabilities include the Norwegian Kongsberg short-range National Advanced Surface-to-Air Missile System (NASAMS), which entered service with the Australian Army in 2025,⁷¹ and three Royal Australian Navy (RAN) air warfare destroyers (DDGs), which provide an additional modicum of active missile defence with their vertical launch systems. The remaining RAN surface fleet, however, lacks adequate missile defence capabilities for self-protection, let alone broader IAMD applications. These capabilities are rounded out by the Royal Australian Air Force (RAAF), which provides one squadron of EA-18G Growler electronic attack aircraft, one of F/A-18F Super Hornets multi-role fighters and three squadrons of F-35A Lightning II fifth-generation stealth fighters. The funding profiles for AIR6500 in the 2016, 2020 and 2024 government investment documents reflect the prioritisation of the joint air battle management system, E-7A Wedgetail airborne early warning and control aircraft upgrades/replacement and upgrades to the over-the-horizon Jindalee Operational Radar Network (JORN), with only a comparatively small allocation for active missile defence.⁷² In other words, the investment is weighted toward situational awareness, sensors and coordination, a critical but incomplete area for a complete IAMD architecture. If implemented as currently structured, the program may well deliver an integrated network capable of tracking inbound missiles at a high standard, but with limited capacity to defeat them. As Malcom Davis of the Australian Strategic Policy Institute has noted, this program structure risks making Australia’s IAMD capability “effectively toothless” without commensurate investment in active defence.⁷³

Australia’s IAMD posture: Capability gaps and 2026 National Defence Strategy

Contemporary conflicts have underscored the centrality of IAMD in the modern missile age. They especially highlight the importance of ground-based air defence to an integrated IAMD architecture, as well as the operational risks of an IAMD force design that is disproportionately reliant on air and naval assets.⁷⁴ However, Australia’s current capability in ground-based air defence is limited in both scale and sophistication. Australia does not field any ground-based ballistic missile defence system. Though the introduction of the NASAMS system greatly improves the ADF’s ability to engage cruise-missile threats, this capability is limited to two batteries, and counter-drone systems remain a critical vulnerability for the ADF. In addition, there remains no ground-based air defence for ballistic missile defence (BMD), and Australia remains overtly dependent on a limited number of air force and naval platforms for that purpose.

The 2026 National Defence Strategy (NDS) and Integrated Investment Program (IIP) provide for a significant boost to Australia’s priority for IAMD.⁷⁵ These documents heed the changing character of war and lessons from contemporary conflicts in Ukraine and the Middle East, with the Australian Government committing an additional A$7.2–10 billion for IAMD over the coming decade.⁷⁶ This funding includes a new medium-range ground-based air defence system, “missile defence to protect critical Defence infrastructure, [and] Defence facilities.”⁷⁷ The 2026 NDS also prioritises passive countermeasures, uncrewed systems and counter-UAS capabilities, as well as “accelerating our operational cooperation [and] advancing our cooperation on integrated air and missile defence,” with the Japanese Self-Defense Force, to protect the ADF from long-range and high-speed missile capabilities.⁷⁸ The Australian Government has also committed to a series of additional measures, including an Advanced Strategic Capabilities Accelerator (ASCA), through which Mission Black Thorn will focus “on rapid development of technology to degrade integrated air and missile defence systems of potential adversaries,”⁷⁹ as well as “investment in research, development and testing of sovereign hypersonic missile defence technologies, designed to counter emerging hypersonic threats.”⁸⁰

These new initiatives are exceptionally welcome news in filling what had become a critical capability gap for Australia. However, these new capabilities remain aspirational, and under current settings, Australia’s air and missile defence capabilities are unlikely to be sufficient to meet the demands of homeland defence, a major international deployment or a major contingency.⁸¹ In addition, concerns have been raised about the availability of the new funding in the 2026 IIP, with claims that the government has reduced the overall defence budget, from A$63.244 billion in 2025-26 to A$62.595 billion in 2026-27 (a difference of A$649 million).⁸² This reduction is achieved by repurposing money from future years to pay for the AUKUS submarine program and the Mogami frigates, with a return of around A$2-3 billion to the Australian Government due to the increasing value of the Australian dollar and funding allocated to sustainment.⁸³

Platform mix and availability constraints

The current state of Australia’s capabilities reflects a fundamental mismatch in how Australia has programmed investment for integrated air and missile defence. Australian strategic documents have long acknowledged the challenge of missile defence. Still, structural and cultural constraints within the Department of Defence have, until 2026, limited investment and the adoption of new technologies. This approach has led to the overreliance on RAAF and RAN capabilities. Sustainment and essential upgrades have also impacted ADF capabilities. One RAN destroyer has now entered refit to upgrade the Aegis Baseline system and enhance its ability to employ SM-6 missiles, strengthening ballistic-missile defence options. This means that in the coming year, one or more of the three DDGs will be offline for upgrades, and if the refit program slips in any way, two or all three Air Warfare Destroyers could be offline in the near to medium term.

The emphasis for much of Australia’s immediate IAMD needs falls on the Joint Air Battle Management System, the E-7A Wedgetail and its potential replacement and the over-the-horizon radar network. These capabilities are essential enablers for sensing, communications and integration, but do not, in themselves, provide the required depth for active missile defence. Looking ahead, the current air warfare destroyers are expected to be supplemented from 2029 by Mogami-class frigates and, from 2032, by a new Hunter-class frigate incorporating an Aegis air-warfare system.⁸⁴ However, reports suggest the Hunter-class frigates will field only 32 VLS cells, severely limiting their interceptor loadouts.⁸⁵ Therefore, much more emphasis needs to be placed on the RAN’s plan to introduce six Large Optionally Manned Surface Vessels (LOSVs) into service from the 2030s to carry missile launch systems.⁸⁶ In 2026, the Australian Army moved toward full operational capability for its new NASAMS batteries; however, only two batteries are currently planned.⁸⁷ Australia’s NASAMS configuration also differs from systems used in Ukraine or by the United States, integrating Australian CEA radars into the kill chain and certifying those radars within it.⁸⁸ The CEA radar component is frequently assessed as a relative strength of the Australian configuration.⁸⁹ In light of the 2026 NDS commitment to a new medium-range ground-based missile system, one straightforward way to enhance the existing system and to achieve ‘speed to capability’ would be to integrate the extended range AIM120 AMRAAM missile. However, two missile batteries will not provide the necessary coverage for Australia’s wider defence enterprise, while there are also questions of whether the Army’s new GBAD system will be focused on cruise missile and conventional air defence or on ballistic missile defence, the requirements of which differ.

Implications for northern basing and coalition operations

A sensor- and air/naval-dominated approach also reduces the ADF’s depth of capability to operate across the IAMD battlespace. It risks forcing air and naval assets into a point-defence role. The defence of northern Australia, especially Darwin and RAAF Base Tindal, in a high-end contingency illustrates the broader problem, particularly as Tindal is being upgraded to host additional US Air Force assets.⁹⁰ Absent substantial and timely reinforcement from US-based forces, Australia may be compelled to employ an Air Warfare Destroyer in a close protective posture for strategic facilities such as the Darwin-Tindal corridor and/or HMAS Stirling and rely on air combat patrols to generate a limited IAMD effect. This matters in a broader coalition and trilateral context because northern Australia is central to Enhanced Force Posture initiatives with the United States — and increasingly with Japan — only further enhancing the requirements for a robust trilateral IAMD system.⁹¹ Figure 5 illustrates that, while Australia has traditionally benefited from strategic distance, that buffer is diminishing as China’s ability to reach northern Australia grows.⁹²

Figure 5. The increasing reach of China’s strike capabilities
DF-21 and DF-26 mainland ranges measured from open-source estimates of associated PLA Rocket Force bases. All ranges are approximate given source limitations.

Source: Map provided courtesy of the Lowy Institute. Version reproduced for USSC.

Options for deepening trilateral cooperation

Overall, Australia is moving toward a requirement for homeland defence systems and architecture that is increasingly aligned with Japan’s capability needs. Further, as the US enhanced force posture in Australia increases, including as Submarine Rotational Force–West stands up at HMAS Stirling, force-protection requirements are only expected to increase. IAMD has been referenced in AUSMIN and Trilateral Defence Ministers’ statements; however, the language remains broad, and there is limited detail on the substance of trilateral IAMD implementation.⁹³

Publicly available statements suggest trilateral cooperation remains at a relatively modest level, emphasising information exchange and data sharing. Bilateral cooperation between Australia and the United States is far more developed, including personnel exchanges; however, trilateral progress appears to be limited in the available record.⁹⁴

Bilateral cooperation between Australia and the United States is far more developed, including personnel exchanges; however, trilateral progress appears to be limited in the available record.

An accelerated pathway may be feasible, although practical integration challenges — technical, organisational and political — remain significant.⁹⁵ The US Indo-Pacific Command’s Integrated Air and Missile Defence Vision for 2028 outlines a network architecture intended to be shared among allies and partners, including an aspirational “any sensor, any shooter” approach to engaging inbound threats, and emphasises the value of an integrated, layered sensor network.⁹⁶ Although current arrangements remain some distance from this 2028 vision, it provides a useful benchmark for identifying sequenced steps toward deeper integration.

The release of the Australian 2026 NDS and the forthcoming updates to Japan’s strategic documents in the same year provide platforms to detail new cooperative measures. This opportunity builds on the identified need in the US 2025 NDS for allies to share more of the burden and on the lessons emerging from the conflicts in the Middle East regarding the importance of IAMD to national, bilateral and trilateral defence measures. A clear area for data sharing, sensor integration and coordination of operational plans provides a basis for accelerated cooperation. From an Australian perspective, the identified need for a national missile defence architecture provides a clear area of cooperation through which the ADF can learn from and benefit from the deep experience and more advanced posture of both Japan and the United States. The purchase of complementary interoperable systems for the Australian Army’s new GBAD capability announced in the 2026 NDS provides a significant opportunity for trilateral collaborative development.

Industrial cooperation and munitions capacity

Integrated production is a major area for potential trilateral cooperation. Australia’s Guided Weapons Plan identifies gaps in surface-to-air and air-to-air missile capacity,⁹⁷ and the 2026 NDS has allocated an additional A$7.2–10 billion (total of A$21–30 billion) across the decade for a system to “deliver a layered, integrated air and missile defence capability to detect, track, counter, withstand and recover from missile attacks.”⁹⁸ However, there is a widely reported global shortage of these missiles and of manufacturing capacity,⁹⁹ with the implication that new and creative solutions are needed to meet the projected manufacturing, procurement and deployment demands. One approach is to disaggregate co-production objectives into different parts: Australia, as a Five Eyes nation already co-producing highly sensitive and advanced systems with the United States under the AUKUS agreement, could contribute to co-production of those components while all three countries coordinate on more mundane items. While this would be challenging from both a technology-transfer and intellectual-property perspective, it warrants consideration as a means of expanding allied capacity.

An Australian MQ-4C Triton long-range surveillance drone in its new Hangar at RAAF Base Tindal, Northern Territory.Source: Australian Department of Defence

All three AJUS countries share similar missile defence systems or families of interceptors. The combined trilateral industrial strength of the three countries and their individual expertise provide a platform for greater cooperation. For example, all three AJUS countries operate the Advanced Medium-Range Air-to-Air Missile (AMRAAM) missile family.¹⁰⁰ US manufacturing is currently restricted, but partnerships with Japan for casings, rocket motors and warheads, and with Australia for the manufacture of sensors, seekers and guidance systems, would enable a federated manufacturing process that would enhance the capabilities of each nation while also providing US forward-based in-region repair, maintenance and sustainment functions, greatly enhancing force readiness and preparedness. Depending on Australia’s choice for a ‘medium-range’ GBAD system, this could also open opportunities for trilateral defence cooperation on systems such as the Patriot PAC-3 MSE missile.

Concerns about technology sensitivity are often raised in this context. However, given the high levels of cooperation already pursued in other domains (including nuclear-powered submarines), expanded collaboration on missile-production enablers would represent a comparatively lower security threshold. Australia also has industrial capacity that could supplement US production in selected areas. In addition, security settings are about risk management. For the United States, the major consideration is not only Japan and Australia’s ability to protect sensitive technology but also a broader assessment of what represents the greater risk — untapped trilateral industrial capability to fill the void of industrial capacity and capability gaps or continued restriction of access to sovereign technology. In an era of US demands for greater alliance burden-sharing, US policy preferences would seemingly suggest that new forms of cooperation and the enablement of the industrial capabilities of its Indo-Pacific allies should remain a high priority.

Enabling technologies and cost-exchange dynamics

A central technical challenge for IAMD is magazine depth. Given the size of China’s arsenal and the unit costs of interceptors, IAMD faces a pronounced cost-exchange problem in which expensive interceptors may be required to defeat lower-cost threats at scale.¹⁰¹ Trilateral cooperation could prioritise directed-energy systems (laser and high-power microwave), research and development into a trilateral low-cost interceptor, counter-drone and enabling capabilities such as advanced radar, electronic warfare and AI-enabled IAMD.¹⁰² Australia’s ASCA has funded two companies under Mission Black Thorn to develop anti-integrated air and missile defence (IAMD) system capabilities for the Australian Department of Defence.¹⁰³ While relevant details are not publicly available, the presence of a dedicated program indicates sustained Australian interest in this line of effort.

Conclusion

More robust IAMD investment enhanced through practical trilateral cooperation — across capability development, production capacity and enabling technologies — is central to meet the needs of national defence priorities in all three countries. Such opportunities also need to be optimised through joint operations planning, joint exercises, information exchanges and data sharing. Investing in areas of trilateral cooperation will only enhance national efforts and improve outcomes. In a rapidly changing strategic environment and a rising China, coalition efforts amongst and within the US alliance network in the Indo-Pacific in IAMD are essential to enhance force protection and credible deterrence postures. Further research should test these arguments against classified force-design assumptions and operational analysis and should evaluate alternative sequencing options for trilateral integration.¹⁰⁴

Conclusions and recommendations

Tom Corben
Research Fellow, Foreign Policy and Defence, United States Studies Centre

The three expert contributions and trilateral Track 1.5 workshop conducted in support of this publication suggest that policy practitioners in Australia, Japan and the United States are generally well-aligned in their thinking about the requirements of trilateral integrated air and missile defence cooperation. Even so, there is evidently much work for all three countries to do to address a range of technical, political, legal and cultural challenges to advancing this agenda, including navigating concurrent needs to rapidly expand production for existing IAMD capabilities and to iteratively innovate new capabilities in response to the changing nature of warfare, and integrating distinct bilateral IAMD agendas into a coherent trilateral whole. The findings below capture the main contours of the three papers included in this report and the workshop discussions, as well as other areas for consideration and further investigation.

The three expert contributions and trilateral Track 1.5 workshop conducted in support of this publication suggest that policy practitioners in Australia, Japan and the United States are generally well-aligned in their thinking about the requirements of trilateral integrated air and missile defence cooperation.

1. The ongoing Ukraine-Russia and Iran-US conflicts hold clear technical, operational and strategic lessons for how Australia, Japan and the United States think about IAMD requirements. While the operational contexts, geographies and politics of these conflicts naturally differ, they have nonetheless highlighted the emergence of affordable precision mass as a key organizing principle for modern strike and IAMD.¹⁰⁵ They have also demonstrated that credibly resourcing these requirements demands that allied countries’ defence industrial bases are prepared to produce at a scale capable of meeting the needs of a protracted conflict, and that they are adaptable enough to innovate in response to changing battlefield conditions and rapid technological change. Traditional strike and interceptor systems will remain relevant to all three AJUS militaries for the foreseeable future, but the time presently required to replace these systems — many of which are produced only by the United States — is too long to meet increasingly acute short-term operational requirements, while the defence economics of the above trends heavily favours lower-cost drones or ‘dumber’ missile systems over time. These technological developments are also changing the ways in which both participating and observing militaries fight, with clear implications for how the AJUS countries think through their future operational planning, force structures and posture decisions at the national, bilateral and trilateral levels. In other words, this real-time evolution in IAMD and strike-based warfare will have clear ramifications across the full-spectrum of Australia, Japanese and US defence policy. Ensuring that these lessons are factored into the scope, scale and priorities of the trilateral agenda will be essential if AJUS is to make credible contributions to regional deterrence and warfighting requirements.

2. For a trilateral IAMD capability to be more than the sum of its parts, the three countries will need to more closely engage on divisions of roles and missions between their forces, including identifying priority investments in their respective national force structures to support those requirements. The expert contributions to this report highlighted that while the US-Australia and US-Japan alliances already factor air and missile defence challenges into their operational planning, efforts to trilateralise those plans remain relatively nascent beyond the recently announced trilateral data-sharing framework.¹⁰⁶ The imperative to deepen operational coordination has only increased. Already facing an increasingly complex targeting problem in China’s diverse air and missile capabilities, all three countries must now also account for an acute global shortage of interceptors and counter-strike weapons, with deliveries of key US weapon systems to Japan, Taiwan and other regional allies facing significant delays due to the US-Iran conflict.¹⁰⁷ Those deliveries — and shortfalls in US inventories — will take years to correct, meaning that the three countries may have to contend with even more difficult decisions about what, when and how to defend critical military assets, bases and operating locations from numerically superior missile and drone attacks.

That, in turn, would suggest that closer trilateral coordination and cooperation will be required to pool and assign kinetic IAMD resources, not simply sensors. Similar to proposals in this report, recent USSC simulation activities have identified “latent link” and “long sense, short defence” models for collective IAMD. This model would essentially see partner countries each invest in national short- to mid-range interception capabilities to defend against direct attacks while simultaneously fielding long-range sensing capabilities to collect and share missile tracking data with other friendly states, even if the sensing country is not itself under attack.¹⁰⁸ There is some evidence that this sort of cooperation is beginning to occur in other minilateral contexts in the region: for example, Japan, the Philippines and the United States conducted IAMD exercises in April 2026 which focused on sharing sensor data and coordinating engagements, including intercepts, across different platforms to defeat complex aerial attacks.¹⁰⁹ Emulating that model in the AJUS context would seem a logical next step.

Of course, this approach will require the AJUS countries to coordinate their investments in new capabilities to ensure that all three are capable of contributing to both detection and interception. This is particularly true for Australia, which possesses ample long-range sensors in the form of aircraft and radars, but lacks the ground-based IAMD capability required to defend against a large-scale missile attack targeting military infrastructure in the country,¹¹⁰ facilities which could also be utilised by US and Japanese forces in a theatre-wide conflict scenario. Both Australia and Japan also lack credible persistent low-earth orbit satellite capabilities that would allow them to better contribute to a trilateral ISR picture largely dominated by the United States, let alone independently identify and engage targets.¹¹¹ Though there will always be trade-offs between national and collective requirements, and the long lead times on procuring these systems means that they will not necessarily solve short-term vulnerabilities, there are evidently capability areas that all three states must fill that would meet both sets of needs.

3. The three countries should more closely coordinate their respective munitions supply chain initiatives, with a focus on missile defence capabilities. Given the shortages of US stockpiles brought about by operations in the Middle East, and well-known bottlenecks for component manufacturing for those capabilities, there are strong industrial and strategic incentives for the AJUS countries to expand their collective capacity to produce priority precision munitions. At first glance, standing up new production capacity for complete missile systems in Australia or Japan would make perfect sense. Japanese companies already produce large segments of US PAC-3 and SM-3 interceptors under license and Tokyo and Washington are looking to expand this cooperation to the SM-6; Australia is gradually increasing its capacity to produce a growing number of US-origin munitions, including some precision variants; and Japanese companies themselves are increasingly interested in exploring missile production opportunities in Australia.¹¹² However, a range of commercial, practical and political factors complicate the strategic logic of those proposals: perceived competition for market share, concerns over information-sharing and technology security, and sheer industrial capacity limitations all act as handbrakes on fully federating precision missile production in each of the three countries.¹¹³ For instance, these factors have constrained Japan’s efforts to scale up PAC-3 production both for its own and for US needs,¹¹⁴ while restrictions remain on missile technology sharing between the United States and Australia despite AUKUS-inspired defence trade control reforms.¹¹⁵

Greater harmonization between the US-Australia Guided Weapons and Explosive Ordnance and US-Japan Defense Industrial Cooperation, Acquisition, and Sustainment initiatives, both of which are seeking to ramp-up co-production for priority precision munitions, seems to be a logical step.

Even so, these realities should not preclude the three countries from more closely coordinating their national and bilateral missile production initiatives to the extent that they can. Specifically, greater harmonization between the US-Australia Guided Weapons and Explosive Ordnance (GWEO) and US-Japan Defense Industrial Cooperation, Acquisition, and Sustainment (DICAS) initiatives, both of which are seeking to ramp-up co-production for priority precision munitions, seems to be a logical step.¹¹⁶ Such trilateral coordination could potentially offset some of the information security and technology-sharing concerns that permeate different bilateral initiatives. Indeed, it is possible to imagine a trilateral division of labour for a catalogue of priority weapons including SM-6, Tomahawk and other missiles whereby Australian companies are licensed to produce more sensitive US missile components, such as seekers, while Japanese companies scale-up production for other less sensitive yet crucial components like rocket motors, already a priority for all three countries.¹¹⁷ Such a federated approach would effectively supplement US capacity in both areas without replacing it or removing commercial opportunities for US primes in either allied country.

Concurrently, Canberra and Tokyo should explore options for rapidly expanding their own bilateral cooperation on missile production in Australia, both to meet tangible operational requirements but also to galvanise action within the US system. For instance, leading Japanese experts have recently highlighted the operational and technological benefits of the Type-12 as a potential long-range anti-ship missile option for the Australian Defence Force.¹¹⁸ Anecdotal evidence also suggests that the comparatively rapid pace of Australia’s collaboration with Norwegian company Kongsberg on the Naval Strike Missile has acted as something of a forcing function for progress in the US-Australia relationship on other strike weapons.¹¹⁹ While neither country realistically seeks to pursue missile industrial base expansion without US input, demonstrating to Washington that the two allies are capable of moving ahead on their own terms can have a galvanising effect on the US system.

4. Along with supply chain integration, the three countries should consider a trilateral cooperative program for new missile interceptor, including drones, to build trilateral equities into IAMD industrial cooperation from the outset. History suggests that commercial and political reservations over licensing missile production can be minimised if the partners decided to pursue collaboration on specific strike and interceptor systems from the outset, including their co-development, co-sustainment and co-production. Indeed, this logic is in part driving US-Australia collaboration on the Precision Strike Missile (PrsM) and Hypersonic Attack Cruise Missile (HACM) and US-Japan hypersonic glide phase interceptor (GPI), with both programs evidencing a far greater degree of practical input from Australian and Japanese industry than in the past.¹²⁰ That the three countries are already exploring options for trilateral work on collaborative combat aircraft (CCA) and composite aerospace materials suggests that there may be appetite for further cooperative projects focused more explicitly on IAMD requirements.¹²¹

In that respect, the three countries could consider jointly nominating a trilateral cooperative program for a specific interceptor or unmanned system — whether a new model or a modernisation program for an existing US model — to build-in trilateral equities across the full lifecycle of the capability from development to fielding. Though other regional defence minilaterals such as the Partnership for Indo-Pacific Industrial Resilience are also exploring options for missile development and production,¹²² the trilateral is better placed to advance this cooperation at the speed of relevance given the level of strategic alignment between its members, the relative development of their industrial and technology bases, and ever improving and aligned information and cybersecurity protocols that will facilitate cooperation on advanced IAMD technologies.

5. The AJUS nations should consider integrating interceptor and missile production factors into trilateral wargaming and crisis simulations to test both present degrees of defence industrial base integration and to identify potential pathways for rapid progress on that agenda when circumstances demand and incentives align. The protracted nature of contemporary conflicts and the rapid innovation of IAMD capabilities within those contexts have demonstrated the need for defence industrial capabilities to be factored into national and collective wargaming alike. There are already signs that other nations are beginning to do just that. The UK Government, for instance, has conducted similar activities in recent years, designed to stress-test supply chain resilience for artillery munitions and unmanned systems amid a protracted conflict in the interests of ensuring that the country is capable of both production and innovation “at wartime speed.”¹²³

There is growing evidence that experts from the Australian, Japanese and US policy communities are conscious of this requirement. For instance, recent simulation activities by the United States Studies Centre including representatives from the AJUS countries (along with South Korea and Taiwan) have shown that the current political appetite for greater operational integration between aligned Indo-Pacific countries’ missile warning, tracking and interception capabilities varies between nations and, overall, remains relatively low. However, they have also underscored clear opportunities for collaboration on other latent enabling elements of a coalition IAMD capability that could facilitate rapid integration if needs arise, including through greater defence industrial base coordination and collaboration.¹²⁴ Further gaming the effects of a range of imaginable crisis scenarios on participant countries’ defence industrial bases would help to anticipate changes in individual and collective IAMD requirements across a variety of futures, and would help to spotlight both where technical and political barriers are likely to exist and where political or strategic circumstances may change national assessments of the cost-benefit profile of integration. Similar activities are beginning to take place within the context of other regional defence industrial partnerships,¹²⁵ suggesting that a bespoke AJUS activity would complement the emerging trilateral IAMD agenda ahead of the expected trilateral live-fire demonstration at Talisman Sabre 2027.