Is Japan joining AUKUS? Not formally – its cooperation will remain limited for now

With Japanese Prime Minister Fumio Kishida visiting Washington this week, rumours have circulated that Japan might soon join the AUKUS security pact between Australia, the United States and the United Kingdom.

Australian Prime Minister Anthony Albanese has downplayed the suggestion, indicating this is not something that will happen soon. He added any cooperation would, for now, be on a project-by-project basis.

What role could Japan possibly play in the alliance? And what are the potential complications?

Australian and US defence and foreign officials gathered for a security summit.
US Defence Secretary Lloyd Austin (left), US Secretary of State Antony Blinken (centre) and Australian Foreign Minister Penny Wong (right) at a security summit in Australia in 2023.
Darren England/AAP

Partner on the ‘Pillar II’ level

Japan has grown increasingly uncomfortable at China’s assertiveness in the Indo-Pacific region, including its “wolf warrior” diplomacy, frequent cyber attacks and harassment of other countries’ ships and aircraft. China also has an ongoing dispute with Japan over islands in the East China Sea.

It’s not surprising, then, that Japan has doubled down on its alliance with the US and security ties with other like-minded nations. It was an early supporter of AUKUS, viewing the alliance as a positive step for regional security that would counterbalance China’s heavy-handed influence.

For some time now, Japan was talked about as a potential fourth partner in the agreement. While the US, UK and Australia have all said they are interested in working with Japan, however, a formal invitation to become a so-called “Pillar I” partner is not likely anytime soon.

The Pillar I level of the partnership involves the US transferring nuclear submarine propulsion technology to Australia. In the meantime, the US will operate a rotational submarine force in Western Australia, until Australia is supplied with refurbished, second-hand US Navy Virgina Class submarines, expected in the mid-2030s.

However, as Rahm Emanuel, the US ambassador to Japan, wrote last week, Japan is about to become the alliance’s first “Pillar II” partner. This level focuses on the sharing of technology related to artificial intelligence, autonomous systems, hypersonic missiles and precision guided munitions.

Japan has advanced technological capabilities that are very much in demand in AUKUS – not just in the Pillar II space, but also within Pillar I.

This includes nuclear research and technology, which could prove useful as the AUKUS partners look to accelerate the quantity, scale and speed of production of nuclear-propulsion submarines. Japan’s expertise does not necessarily extend to weapons-grade nuclear technology, but its civil nuclear energy capability places it at the forefront of potential candidates for engagement on this front.

Japan, however, has its own robust diesel-electric and air-independent propulsion submarine production lines, which does not make participation in AUKUS Pillar I that important for the country. With a much shorter coastline to traverse, its submarines can remain submerged and undetected for the majority of their potential missions – unlike Australia with its long transits between coastal ports.

Nonetheless, Japan has strong capabilities and critical skills in the areas covered by the Pillar II level of cooperation. And Japan has a keen interest in making sure those skills and capabilities are honed and world class. This makes participation in Pillar II key to its national interests.

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Complications to AUKUS expansion

There is a complicating factor, though. AUKUS is still a very new partnership. As such, it is struggling to translate good will and its high level of political support in all three countries into practical benefits. This includes ensuring the drafting and implementation of procedural mechanisms to allow technology transfers to take place between the members.

That is difficult enough to organise between three countries that speak the same language and are culturally very close. Japan, while increasingly seen as a trusted member of western partnerships, remains a country that is culturally very distinct and comes with a deeply ingrained historical reticence toward militarisation.

In addition, Japan has acquired a reputation as being relatively vulnerable to cyber attacks and espionage. More than 70 years of leaning on the US as its defence guarantor has generated what has been perceived as a relatively lax approach toward security, secrecy and maintaining trusted and watertight networks, although recent legislation could address these shortfalls.

While the AUKUS countries have had their own fair share of domestic security challenges and leaks, they see themselves as having learned from past mistakes in a way that Japan has not yet mastered.

My latest book Revealing Secrets (co-authored with Clare Birgin) also points to the trusted inter-generational top secret collaboration that binds Australia with the US and UK as part of the Five Eyes arrangements (along with New Zealand and Canada).

This has not been replicated with any other international partners to quite the same level, extent or duration. This intimate, familial collaboration is not widely understood by outsiders, but cannot be easily replicated and is handled with delicacy by these countries. No one inside AUKUS wants to mess with the dynamics that have enabled such close and trusted ties.

In addition, there is a reluctance to go beyond three core members of AUKUS until the envisioned technology sharing is proven to work. It remains a fragile endeavour, in part because all three members are rambunctious democracies that are going to have multiple elections in the lifetime of the project.

And the next couple of elections – if not, most importantly, the next one in the US in November – is going to consolidate the direction of the alliance.

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A delicate balancing act

Yet, there is a real appetite for encouraging Japan to participate as a trusted collaborator with the US and Australia. This is demonstrated in the trilateral arrangements between them, as well as the quadrilateral ties with India (known as the Quad). Japan is also boosting its ties with the Philippines, South Korea and the United Kingdom.

So, it is a delicate balancing act to encourage Japanese engagement in external security arrangements, while being mindful the country still has a constitution that binds it to a strictly defensive and relatively benign military posture. (It is, however, more willing now to acquire offensive military capabilities.)

No doubt, such initiatives will be frowned upon by China. But this isn’t happening in a vacuum. Indeed, the AUKUS alliance would not be politically possible were it not for the dramatic upsurge in Chinese defence spending and its relentless cyber attacks and “grey zone” operations in the region.

On balance, it appears Japan’s inclusion in a number of discreet components of AUKUS looks like the next natural step in response to these rising challenges.

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