A Perspective from the ROK

The South Korean perspective toward ROK-Australia-Japan cooperation in the Indo-Pacific region is distinctive, given divergent threat perceptions and sensitivity to Chinese responses. What makes South Korea distinctive from the other key US Indo-Pacific allies: Japan and Australia? Above all, the threat from North Korea is more intense, particularly than in Australia. Moreover, dependency on China is felt more acutely, due both to concern for China’s response to a North Korean contingency and the extraordinary degree of economic interdependency at stake. As the Indo-Pacific region has grown more dangerous, Seoul has joined other US allies and partners in doubling down on security ties, but in the late 2010s it was more reluctant than some states, notably Japan, to endorse an agenda extending across the Indo-Pacific. Although it has, in stages since 2021, adjusted its rhetoric in ways criticized by China, reservations have not disappeared. Welcoming the ROK-Japan-Australia minilateral, it remains somewhat wary.

This commentary starts with a brief background of the recent upsurge in trilateral cooperation in the region. Then, it explains the value of this cooperation beyond the existing bilateral ties that South Korea has. Finally, it focuses on the different priorities of the ROK, as well as agendas that Seoul needs to consider for its future contribution to this trilateral cooperation. As the Yoon administration awaits new leadership in Washington and Tokyo, its caution continues.

We are witnessing an increasing number of minilateral groupings in the Indo-Pacific region. This is a relatively new but interesting trend, considering that traditionally, regional countries preferred bilateral cooperation, as represented by the hub-and-spokes system led by the United States. Indeed, these minilateral cooperations often consist of the US and its allies that share similar values, such as liberal democracy and a capitalist market system. Examples of these are the Quadrilateral Security Dialogue and the AUKUS partnership. However, considering that most regional minilateral groupings are US-led, the cooperation between the Republic of Korea, Australia, and Japan is intriguing. It supplements US policy but also hints at more autonomy.

Background

Two major factors for trilateral cooperation between the ROK, Australia, and Japan are (1) the rise of China and its threats to the international rules-based order (also known as the liberal international order); and (2) shared values among the three countries. The first is a geopolitical variable that affects the survival of these three countries. There are academic debates on whether China is challenging the liberal international order or not,¹ but there are certain challenges to this order that they recognize, buttressing trilateral national security ties.

One of the most significant challenges is the threat to the maritime liberal order in the Indo-Pacific, which is evident in the South China Sea. China is currently claiming territorial rights over its self-drawn nine-dash line within the South China Sea and, to support its claim, is constructing and fortifying artificial islands.² In 2016, the United Nations Convention on the Law of the Sea, which is a legal body of the current rules-based order at sea, concluded that China’s maritime territorial claims over the South China Sea are unlawful. However, China continues to fortify its territorial claims, showing that it is violating the liberal maritime order in the South China Sea. One of the biggest concerns for the ROK, Australia, and Japan regarding the violation of the rules-based maritime order in the region is China’s potential control over major sea lines of communication (SLOCs), as the three countries heavily rely on them. The South China Sea is especially critical, not only for commercial reasons but also for strategic ones. The trade flows that transit through the South China Sea include the core energy sources of these three countries, such as crude petroleum and refined oil. For example, South Korea relies on the Middle East  for around 86 percent of its oil import, almost all of which transit through the South China Sea.³ Japan shares a similar concern; around 90 percent of its energy imports rely on the SLOCs of the South China Sea.⁴ Although Australia does not import much crude oil, more than 90 percent of its refined oil imports come from Northeast and Southeast Asia, and these flows also transit through the South China Sea.⁵ Currently, the energy imports that transit there are safeguarded by the norm of freedom of navigation, which is respected by the current rules-based order. If China breaks the liberal maritime order by successfully claiming maritime territorial rights over the South China Sea, it could potentially control the flow of maritime trade in the region. This would give China significant strategic leverage over the ROK, Australia, and Japan by controlling their energy supplies. Therefore, the rise of China and the violation of the maritime liberal order is a shared concern for the three.

The second factor that makes trilateral security cooperation between the ROK, Australia, and Japan possible is their shared values. Generally speaking, shared values include well-known aspects such as liberal democracy and participation in the capitalist market system. However, another important shared value among these three countries is their identity as middle powers. Often, the definition of a middle power is understood based on material capabilities. In reality, it does not simply refer to countries that possess medium-sized economies and militaries within the international community. In particular, when it comes to the foreign policy-making of middle powers, these countries often emphasize three embedded concepts: internationalism, multilateralism, and being good global citizens.⁶ This means that, since middle powers have limited material capabilities, they often prefer utilizing international norms and rules, which comprise the international order, to achieve their best interests in the global arena. In this context, the ROK, Australia, and Japan can be regarded as middle-power countries that do not possess large material capabilities compared to the US and China, and therefore, they prefer to choose diplomatic options over solely military ones when negotiating the norms and rules of the international order. This middle-power reality is related to the concerns over the maritime order discussed above. As middle-power countries, the ROK, Australia, and Japan would prefer multilateral approaches to resolve conflicts peacefully and emphasize shared norms and rules, such as freedom of navigation, as good citizens of the international community.

Values of Trilateral Cooperation from the ROK Perspective

Considering that the liberal maritime order is under threat and is crucial for South Korea’s survival, the greatest benefit of trilateral cooperation among the ROK, Australia, and Japan, beyond existing bilateral cooperation with the US, is having partners to address concerns over the international order together. This becomes especially important given the potential uncertainty of the US commitment to the rules-based order in the region in the future. For instance, presidential candidate Donald Trump has made ambiguous statements regarding the defense of Taiwan and countering Chinese dominance in the South China Sea.⁷ This means that the US may decrease its commitment to the rules-based maritime order in the region if Trump gets re-elected, even though the survival of its partners is heavily dependent on a liberal maritime order. Moreover, this is related to the concerns over the fear of abandonment and increasing burden-sharing demands from the US from the ROK perspective. Not only has Trump made ambiguous statements towards the South China Sea and Taiwan, but he also mentioned “[South Korea is] a very wealthy country” that needs to pay “more” for its own defense. Some of his advisors even commented that Trump mentioned a potential withdrawal of the US Forces Korea in case the ROK government does not increase the burden-sharing.⁸ This issue is related to the fundamental American commitment to the Korean Peninsula, which is not very different from the situation of the South China Sea and Taiwan. Therefore, the ROK, Australia, and Japan need to seek a stronger mutual partnership to uphold the liberal order in the region. From the ROK’s perspective, cooperation among the three countries is valuable in the case of decreased US commitment.

Trilateral cooperation also improves the ROK’s defense posture against North Korea, an enduring security threat to South Korea, of even greater concern due to its tightening security relationship with Russia. For the first time in 24 years, President Vladimir Putin visited Pyongyang in June 2024, which puts Seoul in a less favorable position in the balance of power on the peninsula. Some ROK experts have warned of potential involvement by Moscow in future conflicts there.⁹ Russia can shape the perceived balance of power on the peninsula in favor of the DPRK. This means that South Korea should seek potential partners to reshape the balance of power in its favor. In fact, during the first trilateral defense ministerial talks among the ROK, Australia, and Japan at the 2024 Shangri-La Dialogue, South Korea raised the North Korean threat as one of the key topics of discussion.¹⁰

The Priorities and Assessment

One of the uncomfortable realities from the ROK’s perspective is that North Korea is a second-tier priority for Australia and Japan, while the Chinese threat to the liberal maritime order in the Indo-Pacific is a higher priority. For instance, Australia’s 2024 National Defence Strategy mentions that the “Increasing strategic competition between the US and China is a primary feature of Australia’s security environment… Our primary area of military interest… encompassing the Northeast Indian Ocean through maritime Southeast Asia into the Pacific.”¹¹ Meanwhile, North Korea is only briefly mentioned in the booklet, which implies that it is not a high priority.¹² Compared to Australia, Japan has a higher awareness of the security environment on the Korean Peninsula due to direct missile threats from North Korea. Nonetheless, in the 2024 Japanese Defense White Paper, while the issues surrounding the South China Sea and the East China Sea are mentioned as major security concerns in the Indo-Pacific region, North Korean missile threats are not mentioned.¹³ This means that Japan also prioritizes maritime security issues in the Indo-Pacific region compared to threats posed by North Korea.

However, from Seoul’s perspective, the priorities are the opposite. A larger concern is the increasing North Korean threat, and China’s challenges to the rules-based maritime order are a secondary priority. Indeed, North Korea is also a threat to the international rules-based order, but the nature of Pyongyang’s threat is different. The DPRK is not directly threatening the maritime rules-based order (although it is violating it through the smuggling of oil) in a similar manner to China, and therefore, it is not immediately affecting the survival of Australia and Japan by violating the norm of freedom of navigation in maritime domains. This means that Australia and Japan may not be interested in allocating more resources for deterrence against North Korea and may instead assign more military assets to the preservation of the liberal maritime order. South Korea may not gain as much as expected from the trilateral cooperation in terms of deterrence against North Korea.

Agendas to Consider: Maritime Security

Then, what should Seoul consider in terms of agenda-setting for trilateral cooperation between the ROK, Australia, and Japan? The big question that the ROK needs to answer is how to attract Australia and Japan to the defense of the Korean Peninsula despite the existing divided priorities. South Korea needs to acknowledge that deterrence towards North Korea and the preservation of the liberal maritime order in the Indo-Pacific can be connected agendas. This means that by increasing the ROK’s commitment to the maritime rules-based order in the Indo-Pacific, it can invite increased commitment from Australia and Japan to the defense of the Korean Peninsula against the DPRK. By emphasizing North Korea’s threat to the liberal international order together with South Korea’s increased role in protecting rules-based maritime order, the ROK can affirm these two issues are not separate from each other. To achieve this, the ROK needs to consider allocating some of its naval assets for a broader Indo-Pacific deployment to show its commitment to the rules-based order in the region. Currently, South Korea’s Indo-Pacific Strategy does not include a clear action plan although the strategy emphasizes the value of minilateral cooperation.¹⁴ Considering shared security concerns among the ROK, Australia, and Japan, Seoul needs to connect the Korean Peninsula issue to broader concerns over the maritime security in the Indo-Pacific through the trilateral cooperation, thus emphasizing its position as a good citizen within the current international rules-based order and that the North Korean threat is another significant concern for the liberal order that the three countries need to address together. The three can consider making a joint statement on the North Korea security issue.

Currently, South Korea’s commitment to the liberal maritime order is quite limited compared to that of Australia and Japan despite its importance regarding national survival. While Australia and Japan conduct their annual naval deployments toward a broader Indo-Pacific region, including the South China Sea, to show their commitment to the rules-based maritime order, the ROK does not.¹⁵ South Korea may try to give meaning to its Annual Cruise Training, which is deployed to different parts of the world every year to familiarize its naval midshipmen with sailing duty. So far, the ROK Navy (ROKN) has not conducted an “Indo-Pacific Deployment” as part of the Annual Cruise Training. It could add the “Free and Open Indo-Pacific” to its deployment to show increased commitment to the liberal maritime order. As the training is designed for midshipmen who will become future leaders of the ROKN, it can be even used as an opportunity to educate them on the values that they serve.

Trilateral cooperation between the ROK, Australia, and Japan can serve as a valuable minilateral commitment to the liberal rules-based order, which is critical for the survival of the ROK. Given the shifting geopolitical dynamics in the region such as China’s increasing maritime threats, strengthening ties between Russia and the DPRK, and the potential for reduced US commitment to regional security, this minilateral alliance has become even more crucial. While there are differences in security priorities among the three countries, these can be bridged through negotiation and issue linkage. From South Korea’s perspective, it is particularly important to connect the North Korean security issue with the broader threats to the liberal international order in the Indo-Pacific. To advance this agenda, Seoul must increase its commitment to the liberal maritime order by enhancing the ROKN’s presence in the region. Indeed, this is not an easy decision to take for South Korea considering its economic reliance on China as well as domestic political reasons. If the ROK decides to make an increased commitment to the current rules-based maritime order, Beijing can pressure Seoul with economic means in a similar manner to the Terminal High Altitude Area Defense (THAAD) system installation in 2017. However, South Korea needs to understand that the shift of liberal maritime order in the Indo-Pacific will make its security environment even more dangerous considering that dominance of the South China Sea by China means control over the ROK’s energy trade transits through the critical SLOCs. Moreover, the course of cooperation may be influenced by future domestic political discussions. For instance, due to the concerns over the economic retaliation by China in response to the ROKN’s increased presence, South Korea’s domestic political discussion may not agree with the deployment of the ROKN in a contested area of the Indo-Pacific. Nonetheless, considering the importance of upholding the liberal international order, the ROK should seek ways to increase its commitment to the partnership through the deployment of the ROKN, regardless of domestic political backlash.