In the summer of 1963, British mandarins in Whitehall were left scratching their heads about a peculiar suggestion from Kitamura Takeshi, the Japanese secretary-general of the national defence council. He proposed an Anglo-Japanese joint R&D collaboration programme on military technology. Japan’s new ‘pacifist’ constitution, combined with its wartime history, left the British surprised, though mildly supportive of further talks. Indicative of some of these pressures on Japan’s geopolitical position, the wider Japanese government quickly retreated from the idea, almost ‘embarrassed by the lengths Mr Kitamura had gone’, regarding defence cooperation.

Over 60 years later, the defence ministers of Australia, the United States and the United Kingdom (AUKUS) announced that scoping talks will begin with an eye on including Japan in the wide-ranging Pillar II – the technology collaboration element – of the AUKUS trilateral defence and security partnership. Indeed, in stark contrast to the relatively low-posture approach to geopolitics that Japan adopted for large parts of the Cold War – known as the ‘Yoshida Doctrine’ after its creator, Prime Minister Yoshida Shigeru – this move comes during a week that will see a major announcement on the US-Japan Security Alliance and an additional ‘historic US-Japan-Philippines trilateral meeting’.

It is important to stress that this announcement solely concerns Pillar II of the AUKUS arrangement. Unlike its headline grabbing Pillar I – to secure for Australia a fleet of nuclear-powered attack submarines – Pillar II focuses on collaboration in eight advanced military capability areas: artificial intelligence (AI); quantum technologies; innovation and information sharing; cyber; autonomous undersea systems; hypersonic and counter-hypersonic; and electronic warfare. For the Japanese, Pillar I may currently be a bridge too far, with nuclear propulsion remaining controversial domestically and viewed with scepticism by Prime Minister Kishida Fumio, as highlighted by his comments during the Liberal Democratic Party (LDP) leadership contest. Among the AUKUS partners, Australia and Britain in particular do not wish to complicate the already herculean task of delivering a nuclear submarine capability.

Since its inception, there have always been musings of turning AUKUS into JAUKUS, an acronym born from White House Press Secretary Jen Psaki’s joking dismissal of the suggestion in September 2021. For the most part, Japanese officials played down the idea of joining at the time. What was notable was that when the story surfaced again in the Spring of 2021 – through the Sankei Shinbun  newspaper – it was the Japanese who were approached with the idea of joining rather than vice-versa. Whether it was the UK Parliament’s foreign affairs select committee in August 2023 or American ambassador to Tokyo Rahm Emanuel in April 2024, suggestions of JAUKUS usually came publicly from elements of the AUKUS nations, rather than Japan itself.

The international context has changed to such an extent since AUKUS’ inception, however, that a JAUKUS pact would appear beneficial. In the wake of the 2022 Russian invasion of Ukraine, the security environment has shifted to the extent that Japan has been forced to take stock. It’s three national security documents of 2022 – National Security Strategy (NSS), National Defence Strategy (NDS), and Defence Buildup Programme (DBP) – were followed eight months later by Defense of Japan 2023, which identified China and North Korea as posing, respectively, ‘an unprecedented and the greatest strategic challenge’ and a ‘grave and imminent threat’. It also highlighted Russian aggression as breaching ‘the very foundation of the rules that shape the international order’. In this new paradigm of rule breaking and increased military activities in East Asia, an effective deterrence was deemed vital.

This is where JAUKUS’ definition will prove crucial. JAUKUS would not be a security alliance like the formal North Atlantic Treaty Organisation (NATO), or a non-binding collective security agreement like the Australia, New Zealand, United States Security Treaty (ANZUS). While Japan does have bilateral defence and security arrangements with all three members of AUKUS, only the United States – through the US-Japan Security Treaty of 1951 and its 1960 revision – is committed to defending Japan from outside attack. Thus, in terms of conventional deterrence, the signalled upgrade to the Security Treaty – the ‘biggest’ in over 60 years – that will shortly be announced, is of far greater importance to Japan.

What JAUKUS is, and where it would still be of great use to Japan and fellow AUKUS states, is an industrial and technological strategic alliance. Despite the continued importance of the US-Japan Security alliance for Japanese deterrence – particularly nuclear – there is now a recognition that Japan needs to do more to generate its own conventional deterrence to buttress both the American position in the Indo-Pacific and safeguard its own security.

In the wake of the new strategic documents, the new general strategy to achieve this calls for ‘fundamentally reinforcing Japan’s own capabilities’. These take the form of the so-called ‘counterstrike capabilities’, new expensive capabilities such as uncrewed systems, and increased investment in stockpiles, passive base defences, cyber and space capabilities. Many of these issues would fall under the eight capabilities outlined by AUKUS Pillar II.

To achieve this, the pledge to increase the annual defence budget from 5.4 trillion yen in 2022 ($40 billion) to 8.9 trillion yen in 2027 ($67 billion) will put a strain on Japanese society. Parliamentary debate has focused on a combination of sources for this revenue – ranging from tax increases and debt spending to expenditure cuts and moving money around in the budget – but polling has shown a clear opposition to tax hikes, and with ‘internal fissures… already’ emerging publicly in the LDP, the prime minister may not possess the full political capital required to raise and sustain such spending.

Longstanding issues around multi-national industrial agreements will need to be ironed out. In particular, the issue of security remains a consistent theme in any collaborative work with Japan. Part of the reason the 1960s R&D project failed was that Japan could not guarantee the security of intellectual property or technological secrets. Similarly, today, both the UK and Australia remain concerned about Japan’s lack of security systems. While Japan does now possess an Act on the Protection of Specially Designated Secrets, this does not cover information in the economic and technological fields. In many instances, despite intelligence sharing, the ‘level of trust in the intelligence domain’ between the Americans and Japanese is still said to be ‘inadequate’.

Closer collaboration in the West is to be celebrated. Working together in such a manner is what separates the ‘West’ from those it labels as strategic competitors. For Japan, faced with three close neighbours deemed belligerent and a threat in some form or another, joining AUKUS Pillar II can offer great benefits to its rapid military build-up and modernisation programmes, spreading the costs associated with the capabilities required to produce an effective deterrence. Naturally, it brings its still vast technological and industrial base, which can only be of benefit to the current AUKUS members. Several questions do remain: to what extent has this merger been a US dictate to its fellow members? To what extent does Japan want to be a member of AUKUS Pillar II? And to what extent does Japan’s inclusion benefit the overall aims of Pillar II for its current members? The answers to these may come to define JAUKUS’ success.