On 30th May, the defence secretaries of the three AUKUS partner countries – the United Kingdom (UK), United States (US), and Australia – released a joint statement announcing the first Signature Project of AUKUS Pillar II. In keeping with the overall focus of providing advanced capabilities, this maiden project aims to provide cutting-edge Uncrewed Undersea Vessels (UUVs), with delivery commencing in 2027.
AUKUS Pillar I is centred around the provision of the SSN-AUKUS class of nuclear-powered attack submarines (SSNs), while Pillar II has a broader scope, with the UUVs being only the first of its Signature Projects. This wide lens forms the basis of this week’s Big Ask, in which we asked three experts – as well as Gemini, Google’s Large Language Model (LLM): What should be the next priority for AUKUS Pillar II?
Research Fellow (National Security), Council on Geostrategy
AUKUS Pillar II has for a long time now been associated with a ‘say-do’ gap. Much was promised on the potential of the many strands of collaboration. Several years on from its inception, very little has been programmed.
Part of this is due to uncertainty over what Pillar II was meant to do. To some, it was about regulatory changes to ensure Britain, America, and Australia could work together on these defence technologies more seamlessly; to others, it was about co-developing the technologies which would go on the submarines to be delivered as part of Pillar I; and perhaps to most, it was something grander – a set of bold programmes which would require plenty of funding but which could accelerate the technological dominance of the AUKUS partners in several fields. Given how challenging it has been to get to the point of a first Signature Project, the time is right for a moment of reflection and rationalisation.
In terms of regulatory changes, Pillar II has so far been remarkably successful. Many barriers which had previously existed are no longer there. The continued review and revision of defence industrial policy and laws should continue to fall under the remit of Pillar II, but it is perhaps time for the project strands to be consolidated.
Given the importance of getting Pillar I right, and of the – at times intense – debate over AUKUS (mostly in Australia), Pillar II should be consolidated into focusing on capabilities which will either go in or work with SSN-AUKUS and the next generation of US Navy SSNs. This will include software, sensors, weapons, and collaborative platforms. That is not to say that the three partners cannot work together on projects which fall under what the strands identified, nor that these will not make use of the regulatory element of Pillar II.
Ultimately, some less ‘say’ and some more ‘do’ will go a long way.
Gemini
Council on Geostrategy staff have prompted Gemini, Google’s LLM, to reflect on this week’s Big Ask.
The next priority for AUKUS Pillar II should be the rapid transition from regulatory alignment to the delivery of tangible capability outcomes. Since its inception, Pillar II has been rightly focused on setting the conditions for streamlined cooperation across the British, Australian, and American defence industrial bases. While harmonising export controls and dismantling bureaucratic barriers are essential prerequisites, they are not an end state. The geopolitical environment in the Indo-Pacific, characterised by the largest military buildup in 80 years by the People’s Republic of China, demands urgency that administrative reforms alone cannot provide.
To prevent Pillar II from losing credibility, the three participating governments should establish a dedicated funding structure and a formalised acquisition framework to transition collaborative research into operational mass. Currently, the initiative lacks the specific financial mechanisms required to incentivise industry and move advanced technologies – such as Artificial Intelligence (AI), UUVs, and attritable autonomous systems from the laboratory to the battlespace. Furthermore, narrowing the immediate focus from the expansive eight workstreams to a select number of vital projects would galvanise visible progress.
Procuring interoperable, autonomous systems at scale, akin to the American Replicator Initiative, offers a prime opportunity to demonstrate that the trilateral partnership can generate genuine military advantage. By pooling resources and establishing combined production lines, AUKUS can build supply chain redundancy and buy back essential mass. Ultimately, the success of Pillar II hinges on demonstrating that collaborative defence innovation can translate into deployable hard power capabilities before the strategic balance shifts irreparably.
Adjunct Fellow, Council on Geostrategy, and non-resident Senior Fellow, Australian Foreign Policy Institute
It is difficult to make informed judgments about where the AUKUS partners should concentrate their Pillar II efforts, because much less is known about Pillar II than Pillar I, other than what emerges from occasional joint statements. This void of information has encouraged outside observers to treat it as a sounding board for their pet projects.
What is clear is that Pillar II has struggled to establish momentum, and it is disappointing that it has taken almost five years to agree upon a Signature Project. The choice of payloads and enabling systems for UUVs for the first such project suggests an emphasis among AUKUS partners on supporting Pillar I via the undersea capabilities workstream, although ‘enabling systems’ leaves open the possibility that it could substantially cut across other Pillar II technologies like quantum, AI, and autonomous systems.
It is also noticeable that recent AUKUS joint statements do not mention expanding Pillar II project work to include Asian or other ‘Five Eyes’ partners. That is not to say expansion is definitively off the table, but for now the AUKUS partners appear intent on maintaining a small-yard, high-fence approach to collaboration, and towards supporting and protecting Pillar I as their priority.
While conservative, this approach makes sense given that underwater autonomy is a force multiplier for crewed submarines, potentially forestalling near-term undersea warfare capability gaps from emerging among the AUKUS partners. The UK is having particular problems keeping its Astute class boats seaworthy, while the universal vulnerability of seabed infrastructure is glaring.
International Fellow, Council on Geostrategy; Founder and Principal, Barrier Strategic Advisory; Adjunct Fellow in Naval Studies, UNSW Canberra; and Expert Associate, ANU National Security College
The announcement at the AUKUS defence secretaries’ meeting that the trilateral partnership would focus on payloads for UUVs as a signature AUKUS Pillar II project was welcomed. Almost five years after the AUKUS announcement, the status and achievements of Pillar II had remained unclear, with commentators consistently arguing that it needed a narrower focus.
With its Signature Project now confirmed, the next priority should be to build on the undersea focus and identify the technological advances that can enhance it. This should include undersea capabilities, communications, and Command and Control (C2) of UUVs. Doing so would build on the first Signature Project, while also leveraging existing initiatives across the AUKUS partners and the work already undertaken through the AUKUS Maritime Innovation Challenge 2025 on this topic.
While AUKUS Pillar II may have many threads, and will continue to branch out as trilateral collaboration develops, keeping its goals and Signature Projects clear will be pivotal to success. Developing world-leading undersea capabilities enhances the success of AUKUS Pillar I, while building on the newly announced Signature Project and previous work. Expanding trilateral UUV capability and leveraging initiatives such as the Maritime Innovation Challenge is a positive way to focus cooperation and maximise impact.
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