On 13 September, just days before the announcement of the AUKUS arrangement, Australia’s and South Korea’s foreign and defence ministers met in Seoul. The week before, South Korea displayed a new conventional submarine able to launch long-range ballistic missiles—and on 15 September North Korea test-launched two long-range ballistic missiles, notably while Chinese Foreign Minister Wang Yi was in Seoul. The implications of the dizzying speed of these events will take some time to play out, but it’s clear that here too the regional pace of change has accelerated.

If the AUKUS decision marked a significant strategic shift for Australia, what impact will it have on Australia’s security relationship with South Korea, a formal ally of the US and solid partner of the UK that’s located uncomfortably close to China?

All four previous Australia–Korea 2+2 meetings were marked by lengthy joint statements of shared views on a wide range of issues rather than concrete commitments.

The fifth was no different, with a series of largely unspecific promises to ‘cooperate on existing and evolving security threats’; to establish ‘dialogues’ on cyber, critical minerals supply chains and space policy; ‘to explore new institutional foundations to promote enhanced future defence cooperation’ (an intriguing formulation, left unexplained); and to continue cooperation on defence industry and materiel. In short, a lot of discussion, but few decisions.

But they agreed to increase joint exercises, training, port calls and aircraft visits to improve interoperability. That’s progress, even if, as is likely, modest. The recent conclusion of a potentially useful memorandum of understanding on mutual logistics support and cooperation was noted. Defence research, testing and evaluation appears to have finally got some limited traction, although we’re left to guess about its content. Defence Minister Peter Dutton separately said planning for a new infantry exercise was well advanced, without explaining how regular and intensified bilateral training on each other’s territory (outside the United Nations Command framework) could be conducted while Korea resists negotiating a visiting forces agreement with Australia.

So, the result continues a pattern of modest incremental gains, despite being billed as a meeting of ‘natural partners with shared strategic interests’ facing an ‘uncertain’ strategic environment. Doubtless the Korean government’s unwillingness to risk offence to China underpinned its reluctance to build a more substantive pattern of defence interaction with Australia, while Australia, which has arguably rarely given the Korean relationship the priority it merits, was no doubt focused on the impending announcements in Washington.

Perhaps the most specific, if indirect, reference in the statement of the growing challenges from China to the strategic environment was the ministers’ agreement on ‘upholding freedom of navigation and overflight in the South China Sea … in accordance with international law, including the United Nations Convention on the Law of the Sea’. Ministers called for the code of conduct for the South China Sea to be consistent with international law, to not prejudice the rights and interests of third parties, and to reinforce the existing inclusive regional architecture.

For two countries so heavily dependent on trade through the South China Sea, this was the minimum—but apparently also the maximum—on which, publicly, they could agree in the joint statement.

Australia’s decision to develop a fleet of nuclear-powered submarines, to arm them and other naval and air assets with long-range missiles, and to cooperate with the US and UK on advanced technology is not dissimilar to key parts of Korea’s own ‘Defense Reform 2.0’ program.

The program now goes well beyond capabilities necessary to deal with the North Korean threat and includes construction of an aircraft carrier and submarines able to launch missiles with ranges well beyond the peninsula. Following US President Joe Biden’s decision in May to remove range limits on Korea’s production of missiles, Seoul is developing local construction of a new generation of cruise and other missiles. They offer a more resilient strike and missile-defence capability against the North in the event of a renewed conflict on the peninsula, but they also offer Korea other options.

Three forces are driving this.

Seoul was deeply unsettled by former president Donald Trump’s transactional approach to the US–Korea alliance and his exorbitant claims for increased sharing of the costs of US forces on the peninsula, threats to reduce US force levels, and arbitrary cancellation of joint exercises during his talks with North Korean leader Kim Jong-un. Korea’s confidence in the durability of the American commitment to its security has been shaken, and the US withdrawal from Afghanistan and readiness to incur the wrath of major NATO partner France won’t have helped restore it. Korea fears a US in retreat globally and worries that, despite the Biden administration’s commitment to repair alliances and build a robust Indo-Pacific policy, ‘America first’ may extend well beyond Trump and the Republican Party—and that Trumpism could return.

Second, and related to this, Korea is building a significant defence industry of its own, less reliant on US platforms. Already, according to the Stockholm International Peace Research Institute, Korea has moved into the top 10 defence exporters globally. It intends to develop Korean-made missile defence, an independent satellite surveillance and reconnaissance capability, enhanced cyber defence, military drones, artificial intelligence and robotics. In short, it’s embarked on building a technology-intensive defence capability independent of the US.

Some in Korea are again arguing for it to develop nuclear weapons, and Seoul might see Canberra’s nuclear-propulsion decision as reason to consider developing its own. Unlike Australia, Korea has a sophisticated civil nuclear industry as a platform should it decide to do so. The issue of sovereign control is a live one in Korea, seen most obviously in its ongoing determination to be able to assert operational control of joint US and Korean forces during wartime.

The third force driving this is Korea’s intent to develop an ‘omnidirectional’ defence strategy for countering threats to its sovereignty from other than only North Korea. Clearly, Korea has China principally in mind and is developing capabilities that can reach well into the Chinese mainland. But it also sends signals to Japan, where Korea has been unable, and arguably unwilling politically, to repair longstanding grievances.

So, it’s time to view Korea as a significant regional player rather than largely a US client myopically focused on the Korean peninsula. Australia and Korea have embarked on different defence developmental paths, but the ‘natural partners with shared strategic interests’ need to review the potential advantages from closer bilateral integration. Australia has committed to buy Korean howitzers and may buy Korean armoured personnel carriers, but we need to consider Korea beyond capabilities best suited to the last war rather than to the next one. Samsung, LG and Hyundai, among others, should remind us that Korea is at the forefront of technological development, increasingly an innovator rather than a ‘fast follower’.

But how Seoul will view AUKUS in terms of Korea’s bilateral partnership with Australia remains to be seen. If it senses that alliance relationships are increasingly two-tiered or that Australia has retreated into an Anglo-American alliance at the cost of further developing its regional security and other relationships, there could be limits to the extent to which our bilateral defence cooperation could develop. And Korea, although sharing deep concerns about China, will be uncomfortable about association with their public articulation.

After the 2+2, and despite Australia’s inevitable preoccupation with operationalising AUKUS, both partners must lend substance to the ‘cooperation’, ‘commitments’ and ‘dialogues’ the joint statement foreshadowed. It’s in their ‘shared strategic interests’ to do so.