A next-generation agenda: South Korea-US-Australia security cooperation

Issue brief A next-generation agenda: South KoreaUS-Australia security cooperation

Written by Lauren D. Gilbert, Kester Abbott, Hannah Heewon Seo

Bottom lines up front

• There is great potential for expanded trilateral cooperation among the United States, South Korea, and Australia, but they will need to overcome the “tyranny of distance” and the resulting diverging threat perceptions.

• The three partners should do more to take advantage of the varied applications of critical and emerging technologies, as well as engage further with other partners in the region on these topics.

• The partners can focus their efforts on concretely developing cooperation through public-private collaboration through avenues such as defense industry cooperation, research and development (R&D), and infrastructure projects.

Executive summary:

South Korea and Australia have consistently built upon cooperation as two “middle powers” in a region of ever-growing global importance and dynamism. At the same time, the two countries have bolstered their respective alliances with the United States, building regional bilateral and multilateral collaboration. Ultimately, capitalizing on the potential for growing collaboration and cooperation between the United States, South Korea, and Australia could be key to maintaining security and prosperity in the Indo-Pacific. However, when it comes to bringing several countries together in a collaborative environment, there are inherent challenges to reaching a consensus.

Through this project, next-generation experts from the United States, South Korea, and Australia identified several obstacles to cooperation—namely, differing geostrategic circumstances, diverging threat percep-

tions, different strategies for engaging with China, and a lack of consistent engagement between the countries. Despite this, there are several key opportunities to bolster cooperation—namely, defense industrial cooperation, joint endeavors in science and technology, developing maritime security, and collaborating on engaging additional partner countries and multilaterals.

Therefore, this publication proposes that the countries should aim to

y cultivate defense industry collaboration and public-private cooperation;

y institutionalize relationships and expand joint exercises;

y foster expanded R&D of critical technologies; and

y develop disaster-resilient infrastructure projects and early warning systems.

A next-generation agenda: South Korea-USAustralia security cooperation

Introduction

As the global security landscape continues to evolve, increased coordination among likeminded friends and allies is key to defending their common interests—and this holds true beyond the region in which a country lies. To this end, the Atlantic Council, with support from the Korea Foundation, has built an annual project series to bridge regional perspectives among a rising generation of experts and practitioners in national security and international relations, in order to expand collaboration and improve understanding among the United States, South Korea, and other relevant countries and regions around the world.

This year, to advance this aim, the project took a practical approach to expanding collaboration and improving understanding among the United States, South Korea, and Australia. It focused on defining areas in which flexible, action-oriented, and informal collaborative arrangements among these countries can provide mutual benefits, creating a basis for deeper and more meaningful collaboration moving forward. To advance coordination among the three countries moving forward, it is vital that next-generation experts and officials come together to explore novel methods of collaboration and action-oriented policy recommendations.

Throughout the project, the Atlantic Council and the Korea Foundation convened two private virtual workshops with rising US, South Korean, and Australian junior and mid-career experts who represent the next generation of policymakers, academics, and private-sector leaders who will operationalize this cooperation during their careers. This Next-Generation Network discussed challenges and opportunities for bridging perspectives and bolstering both traditional and nontraditional cooperation in security. Based on the ideas raised during the workshop discussions, the participants offered concrete and actionable recommendations for a next-generation agenda, with a particular emphasis on how policymakers, scholars, and private-sector experts in each region can collectively implement the agenda.

This issue brief provides background on recent events involving cooperation before highlighting an analysis of the key challenges and opportunities at hand, followed by concrete policy recommendations for bridging perspectives on security cooperation among the United States, South Korea, and Australia.

Background

As the regional and global geopolitical environment continues to become more dynamic—through the increasing nuclear and non-nuclear threats from North Korea, China’s maritime aggression and nuclear buildup, Russia’s continued war against Ukraine, and the growing collusion among the three—close coordination among likeminded allies and partners is essential to securing and defending common interests. It is in this context that, over the past several years, South Korea and Australia have consistently built upon cooperation as two “middle powers” in a region of ever-growing global importance, including the 2021 announcement of the Comprehensive Strategic Partnership.1

Most recently, in May 2024, the two countries’ defense and foreign ministers held a 2+2 dialogue in Melbourne. In this meeting, Australia and South Korea committed to reaffirm service-to-service memorandums of understanding, build maritime security, take part in joint and multilateral exercises and trainings, build defense industry collaboration, and more.2 Security and defense cooperation between the two countries is underpinned by the concurrent growth in people-to-people relations, science and technology innovation, and climate security policies, highlighting the two countries’ growing roles as regional and global innovation leaders.

At the same time, the two countries have been bolstering their bilateral alliances with the United States, as well as building regional bilateral and multilateral collaboration. Australia has taken a larger role in maintaining the security environment on the Korean Peninsula through the United Nations Command (UNC), with Australia posting a senior officer as the deputy commander of the UNC Headquarters.3 This shows Australia’s commitment to the defense of South Korea and to the overall defense and deterrence posture in the Indo-Pacific. Admiral David Johnston, chief of the Australian Defence Force, stated, “This appointment will further enable Australia to work closely

1. “Australia-ROK Comprehensive Strategy,” Consulate of the Republic of Korea, December 14, 2021, https://overseas.mofa.go.kr/aumelbourne-en/brd/m_1958/view.do?seq=751292.

2. “Australia-Republic of Korea 2+2 Joint Statement,” Australian Department of Defence, May 1, 2024, https://www.minister.defence. gov.au/statements/2024-05-01/australia-republic-korea-22-joint-statement.

3. “Australian Officer to Serve as Deputy Commander, United Nations Command in the Republic of Korea,” Australian Department of Defence, September 19, 2025, https://www.defence.gov.au/news-events/releases/2025-09-19/australian-officer-serve-deputy-commander-united-nations-command-republic-korea.

A next-generation agenda: South Korea-US-Australia security

with the ROK [Republic of Korea], the United States and other regional partners to pursue our shared values and security interests for regional peace and stability.”4 Similarly, South Korea has further engaged in US and Australian defense initiatives such as the Talisman Sabre exercise in 2025, in which the South Korean forces took part in an amphibious operation.5 South Korea has also shown great interest in joining projects under AUKUS Pillar II, which is a mechanism between Australia, the United Kingdom, and the United States for jointly developing advanced technologies with military applications and military systems.6 This would be a key step in building the security architecture in the Indo-Pacific, as well as building deter-

rence against mounting regional threats, and furthering South Korea’s role as a growing leader in the defense industry.

All three countries held recent elections, making this an opportune time to develop a new agenda for future cooperation.

Australian Prime Minister Anthony Albanese was reelected and showed a consistent willingness to work with both the United States and South Korea in his first term.7 While it is not yet clear how the second Donald Trump administration will prioritize Australia and South Korea, it appears that the AUKUS deal will survive the Pentagon review and Trump has shown a willingness to continue a high level of cooperation with South

4. Ibid.

5. “Exercise Talisman Sabre 2025 Concludes,” US Navy, August 4, 2025, https://www.navy.mil/Press-Office/News-Stories/display-news/Article/4263100/exercise-talisman-sabre-2025-concludes/.

6. Lewis Jackson, “South Korea Discusses Joining Part of AUKUS Pact with US, UK and Australia,” Reuters, May 1, 2024, https://www. reuters.com/world/south-korea-confirms-talks-aukus-pact-with-us-uk-australia-2024-05-01/.

7. Rod McGuirk and Tristan Lavelette, “Australian Prime Minister Anthony Albanese Wins a Second 3-Year Term,” Associated Press, May 3, 2025, https://apnews.com/article/australia-election-albanese-dutton-251063e866513dfa48b773fb4d6b0d29.

Korea.8 Finally, South Korean President Lee Jae-Myung is still developing his stances on various foreign policy issues but has had success engaging with Trump and has vowed further cooperation with Australia.9 Ultimately, capitalizing on the potential for growing collaboration and cooperation between the United States, South Korea, and Australia could be key to maintaining security and prosperity in the Indo-Pacific.

Challenges

When it comes to bringing several countries together in a collaborative environment, there are inherent challenges to reaching a consensus. Furthermore, when incorporating countries from different linguistic, cultural, and regional backgrounds, these challenges become significantly more pronounced. Throughout the first workshop discussion, next-generation experts from the United States, South Korea, and Australia identified several obstacles to cooperation—namely, geographic complexities, diverging threat perceptions, differing strategies for engaging with China, and a lack of consistent engagement between the countries.

Positioned at opposite ends of a Pacific triangle, South Korea, Australia, and the United States face considerable geographic challenges as they attempt to bolster security cooperation. The US regional alliance system, having long provided Washington with in-theater basing arrangements for stationing its forward-deployed defense assets, has underpinned Washington’s strategic presence in the Western Pacific, making it no stranger to projecting force across vast geostrategic spaces. Still, many in the United States have discussed concerns regarding the “tyranny of distance” and how it would affect sustainability, logistics, maintenance, and more in the case of

conflict or increased tensions.10 United States Forces Korea (USFK) Commander General Xavier Brunson has argued for the strategic value of USFK in overcoming these geographic constraints on US operations in the broader region, saying, “The Indo-Pacific region represents many challenges . . . largely defined by the tyranny of distance, especially when it comes to sustainment.”11

By comparison, resource-constrained middle powers like South Korea and Australia have often found their strategic bandwidth consumed by more immediate security concerns or capability gaps. This has constrained their ability to sustain defense commitments beyond select Indo-Pacific sub-regions in which their respective equities are most directly engaged and effective.

For Australia, recent strategic documents such as the 2023 Defence Strategic Review (DSR) and 2024 National Defence Strategy (NDS) have identified a “strategy of denial”—aimed at deterring a potential adversary’s attempt to project power against Australia and upholding a favorable regional strategic balance—as Canberra’s overall framework for defense planning.12 To achieve these deterrence objectives, Australian policymakers have focused such efforts in its “primary area of military interest,” which spans the northeast Indian Ocean through maritime Southeast Asia and into the Pacific.13 Despite Canberra’s long-term regional balance strategy, as articulated in the aforementioned strategic documents and in Albanese’s declaration at the 2023 Shangri La dialogue that Australia is “not opting out of the big questions on security and stability” in the region, Australia remains less directly engaged in issues of North Asian security dynamics—including potential flashpoints such as North Korea, Taiwan, the East China Sea,

8. David Crowe and Paul Sakkal, “‘AUKUS Is Safe’: Pentagon Backs Plan to Sell Submarines to Australia, Report Says,” Sydney Morning Herald, September 30, 2025, https://www.smh.com.au/world/north-america/aukus-is-safe-pentagon-backs-plan-to-sellsubmarines-to-australia-report-says-20250930-p5myue.html; “President Donald Trump Hosts a Bilateral Meeting with President Lee Jae-myung of the Republic of Korea,” White House, August 25, 2025, https://www.whitehouse.gov/gallery/president-donaldtrump-hosts-a-bilateral-meeting-with-president-lee-jae-myung-of-the-republic-of-korea/.

9. Kim Eun-Jung, “Lee, Australian PM Agree to Bolster Cooperation on Addressing N. Korea’s Nuclear Issue,” Yonhap News Agency, June 17, 2025, https://en.yna.co.kr/view/AEN20250617002100315.

10. “Advance Policy Questions for Admiral John C. Aquilino, USN Nominee for Commander, U.S. Indo-Pacific Command,” US Senate Armed Services Committee, March 23, 2021, https://www.armed-services.senate.gov/imo/media/doc/Aquilino_APQs_03-23-21. pdf.

11. “Gen. Brunson Stresses Strategic Value of USFK Presence in Overcoming ‘Tyranny of Distance,’” Korea JoongAng Daily, May 16, 2025, https://koreajoongangdaily.joins.com/news/2025-05-16/national/defense/Gen-Brunson-stresses-strategic-value-of-USFKpresence-in-overcoming-tyranny-of-distance/2309010.

12. “National Defence: Defence Strategic Review 2023,” Australian Department of Defence, 2023, https://www.defense.gov.au/ about/reviews-inquiries/defense-strategic-review; “2024 National Defence Strategy and 2024 Integrated Investment Program,” Australian Department of Defence, 2024, https://www.defense.gov.au/about/strategic-planning/2024-national-defense-strategy-2024-integrated-investment-program.

13. “2024 National Defence Strategy and 2024 Integrated Investment Program,” 21.

A next-generation agenda: South Korea-US-Australia security

South Korea, Australia, and the United States are positioned at opposite ends of a Pacific Triangle. Regional allies and partners, including Japan, New Zealand, Pacific Islands countries, and members of ASEAN, are in green.

and the South China Sea—than in those of its more immediate subregions.14

In South Korea’s case, these geographic influences are arguably stronger obstacles to its own regional security engagement, as frequent North Korean provocations and the larger challenges posed by North Korea have constrained Seoul’s strategic ambition by keeping its attention closer to home.15 Even when Seoul has sought to widen its strategic aperture— including Lee Myung-bak’s 2008 Global Korea, Moon Jae-In’s 2017 New Southern Policy, and Yoon Suk Yeol’s 2022 Glob-

al Pivotal State—its efforts struggled to garner sufficient resources and sustain momentum.16 Consequently, to generate meaningful strategic effects on shared regional security issues alongside the United States, Seoul and Canberra will need to navigate competing security priorities and address capability shortfalls that have historically limited sustained security engagement in the broader region.

The tyranny of distance further exacerbates the key challenge trilateral cooperation faces—the differences in threat perception between the countries. South Korea’s security focus has

14. Anthony Albanese, “Keynote Address,” speech at the IISS Shangri-La Dialogue, 20th Asia Security Summit, Singapore, June 2, 2023, https://www.iiss.org/events/shangri-la-dialogue/shangri-la-dialogue-2023/keynote-address/.

15. Wongi Choe, “Australia and Korea: Middle Powers in Uncharted Waters,” in Lena Duchene and Chris Khatouki, eds., Australia and Korea: Middle Power Parallels, Asia Society Australia, July 2022, https://asiasociety.org/sites/default/files/2022-06/Australia_and_ Korea_Middle_Power_Parallels_Report.pdf.

16. Kester Abbott, “What Does Lee Jae Myung’s Victory Mean for South Korea’s Indo-Pacific Strategy, and for Australia?” United States Studies Centre, University of Sydney, June 26, 2025, https://www.ussc.edu.au/what-does-lee-jae-myung-s-victory-mean-for-south-korea-s-indo-pacific-strategy-and-for-australia.

remained mainly on North Korea, given its geographic proximity, the potential for conflict, and the larger question of the unresolved political division of the Peninsula. By contrast, Australia’s 2024 NDS expresses concern over China’s military expansion and the risk of escalation, particularly in the Taiwan Strait and the South China Sea, as well as the implications that a conflict with China would have for Australia’s national security.17 Canberra also faces growing maritime concerns as Chinese naval activity increases in its exclusive economic zone.18 Meanwhile, the United States straddles both issues, maintaining deterrence against North Korea while managing strategic competition with China. The apparently deepening alliance between North Korea and China—alongside North Korea’s formalized Comprehensive Strategic Partnership with Russia and growing signs of a trilateral partnership among the three countries—is not yet seen as a serious, cohesive threat to the region. Signs of the tightening China-Russia-North Korea security axis during the August 2025 Victory Day celebrations in Beijing—followed by similar signs during the October 2025 eightieth anniversary of North Korea’s ruling party in Pyongyang—could heighten the alertness of the United States, South Korea, and Australia.19 Yet, Australian and South Korean views of Washington’s relative decline in influence in Asia, along with its “America First” policies and rising trade protectionism, have encouraged the allies to place greater emphasis on enhancing their sovereign defense capabilities. While Australia and South Korea are advancing many of these efforts through the parameters of their respective alliances with the United States, a significant misalignment in security agendas arising

from these challenges could hinder cohesive military planning and resource allocation, leaving cooperation vulnerable to external shocks such as leadership changes.

Contrasting risk tolerances regarding China create another key challenge. Washington is increasingly pressuring its partners, particularly in Asia, to align more explicitly, leaving less room for hedging positions.20 This creates a dilemma for South Korea, which has long pursued a dual-track policy of “economy with China, security with the United States.”21 Seoul has sought to avoid antagonizing Beijing, especially after experiencing economic retaliation and a diplomatic freeze following the 2016 Terminal High-Altitude Area Defense (THAAD) deployment, which cost $15.6 billion in tourism revenue alone.22 Although Lee has acknowledged the shrinking viability of this balancing strategy, deeper security cooperation with Australia and the United States—especially in military activities beyond the Korean Peninsula—could provoke renewed tensions with Beijing.23 Australia, by contrast, has been more willing to align proactively with the United States, despite temporarily suffering tariffs and bans on barley, wine, coal, and beef in 2020 by China.24 These different risk tolerances complicate consensus on the “China issue.” Without such an alignment, trilateral security cooperation is likely to remain limited.

Another obstacle to developing trilateral security cooperation is the inconsistency with which Seoul and Canberra have regarded each other as critical partners on shared security challenges. Their respective strategic imaginations and perceived hierarchies of relationships have rarely placed the other at the

17. “2024 National Defence Strategy and 2024 Integrated Investment Program.”

18. Euan Graham, “China’s Warships Reveal More Than a Need to Strengthen the ADF,” Strategist, Australian Strategic Policy Institute, March 27, 2025, https://www.aspistrategist.org.au/chinas-warships-reveal-more-than-a-need-to-strengthen-the-adf.

19. Nectar Gan, Yong Xiong, and Gawon Bae, “Kim and Putin Top XI’s Guest List for China’s Huge Military Parade in Defiant Show of Unity,” CNN, August 28, 2025, https://www.cnn.com/2025/08/27/china/china-military-parade-putin-kim-intl-hnk; Joyce Lee and Josh Smith, “North Korea Holds Military Parade, Shows off New Intercontinental Missile,” Reuters, October 11, 2025, https://www. reuters.com/world/asia-pacific/north-korea-holds-military-parade-shows-off-new-intercontinental-missile-2025-10-10/.

20. Kanishkh Kanodia, “US Indo-Pacific Allies Are Unhappy about Trump’s Defense Demands. But They Have to Comply,” Chatham House, July 14, 2025, https://www.chathamhouse.org/2025/07/us-indo-pacific-allies-are-unhappy-about-trumps-defense-demands-they-have-comply.

21. Evans J. R. Revere, et al., “How Will South Korea Navigate U.S.–China Competition in 2025?” Brookings, January 22, 2025, https:// www.brookings.edu/articles/how-will-south-korea-navigate-us-china-competition-in-2025/.

22. Darren J. Lim and Victor Ferguson, “Chinese Economic Coercion during the THAAD Dispute,” Asan Forum, July 29, 2019, https:// theasanforum.org/chinese-economic-coercion-during-the-thaad-dispute/.

23. Victor Cha, “Statesmen’s Forum: His Excellency Lee Jae Myung, President of the Republic of Korea,” Center for Strategic and International Studies, August 25, 2025, https://www.csis.org/analysis/statesmens-forum-his-excellency-lee-jae-myung-presidentrepublic-korea.

24. Georgia Edmonstone, “China’s Trade Restrictions on Australian Exports,” United States Studies Centre, University of Sydney, April 2, 2024, https://www.ussc.edu.au/chinas-trade-restrictions-on-australian-exports.

A next-generation agenda: South Korea-US-Australia security cooperation

center, both at the official and public levels.25 While this dynamic has been reinforced by the US “hub-and-spokes” bilateral security architecture and a decades-long institutional habit of turning to Washington to address key security challenges, Seoul and Canberra have missed important opportunities in which deeper engagement with one another could have provided valuable support in fulfilling their respective regional and national strategic objectives. For example, Moon’s New Southern Policy sought to widen South Korea’s strategic aperture and strengthen ties across Southeast Asia, yet Australia was absent from that strategy despite clear areas of alignment.26 Australia’s approach to South Korea has been no less inconsistent. Australia’s 2017 Foreign Policy White Paper

identified South Korea as a regional power of consequence but, just three years later, the 2020 Defence Strategic Update omitted it as a strategic partner entirely.27 The launch of the Comprehensive Strategic Partnership between the two countries in 2021 sought to resolve this neglect and represented South Korea’s most ambitious strategic partnership at the time beyond its alliance with Washington. Yet, when contrasted with Canberra’s rapidly expanding ties with Japan and India—and Seoul’s concurrent prioritization of other relationships, including with Japan and trilateral security cooperation with the United States—the Australia-South Korea partnership appears to reflect leaders’ current view of the relationship as one to sustain rather than to significantly elevate.

25. Peter Dean, “The South Korea-Australia Partnership: State of Play,” United States Studies Centre, University of Sydney, October 23, 2024, https://www.ussc.edu.au/the-south-korea-australia-partnership-state-of-play.

26. Peter Dean and Kester Abbott, “Buffeting Winds: Moving the Australia-ROK Partnership Forward in a Period of Uncertainty,” United States Studies Centre, University of Sydney, May 1, 2025, https://www.ussc.edu.au/moving-the-australia-rok-bilateral-partnershipforward-in-a-period-of-uncertainty.

27. Dean, “The South Korea-Australia Partnership,” 4.

Opportunities

While the aforementioned challenges pose obstacles, there are also numerous opportunities to advance trilateral cooperation. While many of the challenges are based in the long-standing strategic landscape of the region, building upon new avenues of both traditional and nontraditional security cooperation offers key areas of promise. Throughout the second workshop discussion, next-generation experts identified several key opportunities to bolster cooperation—namely, defense industrial cooperation, joint endeavors in science and technology, developing maritime security, and collaborating on engaging additional partner countries and multilaterals.

First, federated defense industrial cooperation offers a significant opportunity for the United States, South Korea, and Australia to build momentum in developing a trilateral security partnership. By pooling their respective defense capabilities and technical expertise, the three countries can help ensure regional security and overcome persistent logistical and resourcing challenges facing the United States in the Indo-Pacific. China’s expanding anti-access/area-denial (A2/ AD) systems have created new operational challenges for sustaining forward-deployed US forces in conflict. While the United States has undertaken important efforts to mitigate these threats, such as prepositioning munitions across the Indo-Pacific, these stockpiles and the accompanying storage facilities would remain exposed to adversary strikes.28 As Beijing’s long-range strike and subsurface warfare capabilities increasingly threaten US logistical and resupply operations, South Korea’s geographic proximity to a regional contingency and Australia’s strategic depth provide options to support forward deployments while also developing shared capabilities that could offset enduring limitations facing the US defense industrial base (DIB). Enhancing interoperability among the three partners is especially critical given that the US DIB is current-

ly constrained in meeting allied demand, countering China’s growing industrial capacity, and ensuring the timely delivery of essential defense materiel to the three countries and their partners’ forces in a conflict.29

Existing multinational frameworks, such as the Partnership for Indo-Pacific Industrial Resilience (PIPIR), offer a vital avenue for this effort. Launched in 2024 and reinforced since, PIPIR provides a mechanism for identifying comparative industrial advantages, reducing duplication, and aligning production timelines to better resource collective deterrence.30 To date, such US efforts have focused on bilateral initiatives, such as leveraging South Korea’s shipbuilding capabilities and Australia’s developing Guided Weapons and Explosive Ordinance (GWEO) enterprise.31 Yet, closer trilateral coordination would strengthen this relationship and be beneficial to broader PIPIR ecosystems. Aligning Australian and South Korean industrial sectors as complementary to the US DIB would maximize the benefits of geographic proximity to potential flashpoints and would provide a more resilient defense industrial foundation for resourcing future collective extended deterrence efforts in the Indo-Pacific.

Another key area of opportunity is cooperation on further R&D and training for critical technologies. The three countries have all recently pushed for further funding of emerging and critical technologies to bolster both national security and domestic markets. Trump has launched the President’s Council of Advisors on Science and Technology (PCAST) to spearhead US innovation and competitiveness, Albanese’s several initiatives include the Advanced Strategic Capabilities Accelerator’s (ASCA) Emerging and Disruptive Technologies (EDT) program to “advance the development of existing and new capabilities that help deter hostile acts against Australia and in our region,” and Lee has made artificial intelligence (AI) a key pillar of his economic plan for South Korea as a “super innovation econ-

28. Kester Abbott, “Empowering Allies’ Defense Industrial Capabilities to Bolster Deterrence in Asia,” Pacific Forum, August 15, 2025, https://pacforum.org/publications/yl-blog-147-empowering-allies-defense-industrial-capabilities-to-bolster-deterrence-in-asia/.

29. Adam Kozloski, “In a War against China, the US Could Quickly Exhaust Its Weapons. A New Indo-Pacific Defense Initiative Might Be the Answer,” Atlantic Council, October 17, 2024, https://www.atlanticcouncil.org/blogs/new-atlanticist/in-a-war-against-chinathe-us-could-quickly-exhaust-its-weapons-a-new-indo-pacific-defense-initiative-might-be-the-answer/.

30. Adam Kozloski and Markus Garlauskas, “In the Indo-Pacific, US Defense Industrial Partnerships Go Much Deeper than AUKUS Submarines,” Atlantic Council, July 15, 2025, https://www.atlanticcouncil.org/blogs/new-atlanticist/in-the-indo-pacific-us-defenseindustrial-partnerships-go-much-deeper-than-aukus-submarines/.

31. Peter K. Lee, “An Indo-Pacific Allied Shipbuilding Enterprise,” Asan Institute for Policy Studies, January 24, 2025, https://www.asaninst.org/bbs/board.php?bo_table=s1_2_eng&wr_id=87&sfl=wr_subject%7C%7Cwr_content&stx=World+War&sop=and; Cynthia R. Cook and Kester Abbott, “Partnering for Forward Deterrence in the Indo-Pacific: Overcoming Barriers to US-Australia Cooperation on Australia’s GWEO Enterprise,” United States Studies Centre, University of Sydney, July 2025, https://www.ussc.edu.au/ partnering-for-forward-deterrence-in-the-indo-pacific-overcoming-barriers-to-us-australia-cooperation-on-australia-s-gweo-enterprise.

A next-generation agenda: South Korea-US-Australia security

omy” and plans to make South Korea one of the top nations in AI.32

AUKUS Pillar II has also created a key venue for cooperation on developing advanced capabilities, with six of its eight working groups focusing on technology.33 While formally joining AUKUS is not viable, South Korea could cooperate with specific projects or serve an observer or associate role in select

working groups that include less contentious areas such as AI ethics, dual-use cases for quantum, and cyber resilience. Focusing on the potential of dual-use technologies—such as AIbased navigation systems, autonomous underwater vehicles, or long-range radars—provides alternatives for cooperation on low-risk technologies. Further, the United States, Australia, and South Korea can take leading roles in the norms and governance element of critical and emerging technologies.

32. “Fact Sheet: President Donald J. Trump Launches PCAST to Restore American Leadership in Science and Technology,” White House, January 23, 2025, https://www.whitehouse.gov/fact-sheets/2025/01/fact-sheet-president-donald-j-trump-launches-pcastto-restore-american-leadership-in-science-and-technology/; “Albanese Government Invests in Australian Innovation to Give Defence a Technological Edge,” Australian Department of Defence, press release, November 18, 2024, https://www.minister.defence. gov.au/media-releases/2024-11-18/albanese-government-invests-australian-innovation-give-defence-technological-edge; Charlie Campbell, “President Lee Jae-Myung’s Plan to Reboot South Korea,” Time, September 17, 2025, https://time.com/7317953/southkorea-president-lee-jae-myung-cover/.

33. “AUKUS Pillar 2 (Advanced Capabilities): Background and Issues for Congress,” Congressional Research Service, May 21, 2024, https://www.congress.gov/crs-product/R47599.

The United States previously led the development of the Political Declaration on Responsible Military Use of Artificial Intelligence and Autonomy, with both Australia and South Korea signing on as endorsing states.34 South Korea recently hosted the second Summit on Responsible Artificial Intelligence in the Military Domain (REAIM), demonstrating a precedent for it providing a leadership role in issues of norms and governance of emerging technologies.35

Further, maritime security cooperation in Southeast Asia presents a promising avenue for deepening trilateral collaboration. The region serves as a natural geographic convergence between South Korean, Australian, and US strategic priorities. It is also a critical commercial shipping corridor of geoeconomic significance and a central arena of strategic competition across all domains. Although freedom of navigation operations in Southeast Asia have increased in recent years, they do not provide a sustained year-round presence to deter Chinese maritime coercion against Southeast Asian partners.36 Additionally, current US and Australian contributions to bolster Southeast Asian partners’ maritime resilience, such as ad hoc transfers of secondhand vessels or loans for domestic shipbuilding, are helpful but insufficient to match the scale of China’s shipbuilding trajectory.37 A collective shipbuilding effort could mitigate market-driven competition that has often seen US allies and partners bidding against one another, resulting in Southeast Asian states acquiring disparate vessels and systems that require more extensive workforce training programs and already stretched resources to operate. For example, the Australian shipbuilder Austal, which produces patrol boats for the South Pacific, was initially contracted to build offshore patrol vessels (OPVs) for the Philippines, but the agreement collapsed due to rising production costs. South Korea’s Hyundai Heavy Industries later secured the contract to deliver six OPVs instead.38 Therefore, more coordinated South Korea–US–Aus-

tralia trilateral efforts could help mitigate the challenges that arise when Southeast Asian partners struggle to absorb disparate maritime resilience-building initiatives. With US and Australian shipbuilding operating at full capacity, leveraging South Korea’s shipbuilding expertise while drawing on US and Australian strengths in maritime infrastructure development and personnel training would provide a more sustainable and complementary approach.

Beyond the security realm, two main opportunities lie in furthering regional diplomatic engagement with Southeast Asia and the Pacific Islands themselves. The Australia-Republic of Korea 2+2 Joint Statement in 2024 has already recognized the value of the two geographical areas by “[reaffirming] their commitment to ASEAN [Association of Southeast Asian Nations] centrality and ASEAN-led regional architecture and for cooperation with the Pacific Islands Forum.”39 These regions are not only strategically important but provide practical arenas in which the three countries’ complementary strengths can be combined. South Korea’s close diplomatic relationship with Southeast Asia, cultivated through ASEAN+3, provides one source of complementary strength. Australia’s deep-rooted ties with the Pacific Islands, reinforced through the Pacific Islands Forum, offer another. The United States provides the critical security backbone and deterrence capacity that neither South Korea nor Australia can guarantee independently.

All three countries have explicitly incorporated Southeast Asia into their strategic policies, recognizing the region’s position at the crossroads of the Indo-Pacific. For South Korea, ASEAN engagement has been institutionalized since the 1990s, strengthened in the New Southern Policy, and later carried into the Korea-ASEAN Solidarity Initiative in Strategy for a Free, Peaceful, and Prosperous Indo-Pacific under two recent administrations.40 Australia has deepened its ties with ASEAN

34. “Political Declaration on Responsible Military Use of Artificial Intelligence and Autonomy,” US Department of State, last visited October 7, 2025, https://www.state.gov/bureau-of-arms-control-deterrence-and-stability/political-declaration-on-responsible-military-use-of-artificial-intelligence-and-autonomy.

35. “Outcome of Responsible AI in Military Domain (REAIM) Summit 2024,” Ministry of Foreign Affairs, Republic of Korea, press release, October 9, 2024, https://overseas.mofa.go.kr/eng/brd/m_5676/view.do?seq=322676.

36. Raymond Kuo, Contests of Initiative: Countering China’s Gray Zone Strategy in the East and South China Seas (Washington, DC: Westphalia Press, 2021).

37. Peter K. Lee, et al., “Many Hands: Australia-US Contributions to Southeast Asian Maritime Security Resilience,” United States Studies Centre, University of Sydney, November 28, 2022, https://www.ussc.edu.au/australia-us-contributions-to-southeast-asian-maritime-security-resilience#footnote-def-29.

38. Frances Mangosing, “Navy to Order 6 More Patrol Vessels from South Korea,” Cebu Daily News, May 23, 2022, https://cebudailynews.inquirer.net/442806/navy-to-order-6-more-patrol-vessels-from-south-korea.

39. Richard Marles and Penny Wong, “Australia-Republic of Korea 2+2 Joint Statement,” Australian Department of Defence, May 1, 2024, https://www.minister.defence.gov.au/statements/2024-05-01/australia-republic-korea-22-joint-statement.

40. “ASEAN Overview,” Ministry of Foreign Affairs, Republic of Korea, last visited September 1, 2025, https://www.mofa.go.kr/eng/ wpge/m_5466/contents.do.

A next-generation agenda: South Korea-US-Australia security cooperation

through the Southeast Asia Development Partnership Plan (2024–2028) and the ASEAN-Australia Comprehensive Strategic Partnership (2025–2029).41 The United States has similarly prioritized ASEAN in its Indo-Pacific Strategy, pledging sustained diplomatic and security engagement.42 The combination of South Korea’s longstanding ASEAN networks, Australia’s development focus, and US deterrence capacity can deliver complementary benefits through trilateral cooperation.

As the Pacific Islands gain prominence in regional geopolitics, they have emerged as a key arena for cooperation. The Pacific Islands are increasingly central to Australia’s security outlook, as reflected in new agreements with Papua New Guinea.43 South Korea, though a newer player, signaled its interest through the inaugural 2023 Korea-Pacific Islands Summit, while the United States formalized its approach with the Pacific Islands Partnership Strategy and the Pacific Islands Forum’s

41. “Australia–Southeast Asia Regional Development Partnership Plan 2024–2028,” Australian Department of Foreign Affairs and Trade, May 2025, https://www.dfat.gov.au/publications/development/australia-southeast-asia-regional-development-part nership-plan-2024-2028; “Australia’s Regional Partnership with Southeast Asia,” Australian Department of Foreign Affairs and Trade, last visited September 1, 2025, https://www.dfat.gov.au/geo/southeast-asia/development-assistance/australias-regional-partnership-southeast-asia.

42. “The United States’ Enduring Commitment to the Indo-Pacific: Marking Two Years Since the Release of the Administration’s Indo-Pacific Strategy,” US Department of State, February 9, 2024, https://2021-2025.state.gov/the-united-states-enduring-commitment-to-the-indo-pacific-marking-two-years-since-the-release-of-the-administrations-indo-pacific-strategy/.

43. Marian Faa, “Australia and Papua New Guinea to ‘Totally Integrate’ Military in Defense Treaty, Minister Says,” ABC News, September 13, 2025, https://www.abc.net.au/news/2025-09-14/australia-and-png-defense-treaty-to-integrate-military-forces/105770088.

2050 agenda.44 Crucially, all three countries have committed to its 2050 Strategy for the Blue Pacific Continent, which identifies climate change as the region’s most urgent security threat.45

In the long term, trilateral cooperation should also legitimize its purpose beyond the three countries themselves by demonstrating credibility across the Indo-Pacific. While South Korea and Australia often describe themselves as middle powers— particularly in comparison to the United States—their advanced capacities position them well above many regional neighbors. By responding to local priorities, the trilateral can present itself not merely as a strategic bloc against great-power rivalry, but as a trusted and constructive partnership committed to regional stability and development. Ultimately, Southeast Asia and the Pacific Islands are the very opportunities through which trilateral cooperation can be sustained.

Recommendations

At this point in the relationship among the three countries, it is vital to seize the opportunity to develop further understanding and collaboration. Throughout the project, the Next-Generation Network developed several concrete and actionable policy recommendations. These are by no means exhaustive; rather, they reflect topics raised by participants from various backgrounds. Therefore, this publication proposes that the countries should aim to

y cultivate defense industry collaboration and public-private cooperation;

y institutionalize relationships and expand joint exercises;

y foster expanded R&D of critical technologies; and

y develop disaster-resilient infrastructure projects and early warning systems.

Cultivate defense industry collaboration and public-private cooperation. Utilizing the PIPIR framework, the three countries should identify defense industrial capabilities in which their respective industries can complement the US defense industrial base, help address logistical and materiel shortfalls in the US extended deterrence posture in the Indo-Pacific, and ultimately ensure allied defense capabilities provide more than the sum of their parts. Prospective allied contributions, however, must be matched by clear strategic coordination. Washington should engage in scenario-based planning with its allies

to determine which industrial assets can be mobilized during crises or conflicts. While some US allies and partners might accept heavier burdens in peacetime, they might hesitate in contingencies that carry risks of retaliation or horizontal escalation. For example, Australia has expanded security cooperation with the United States through rotational US bomber deployments and submarine sustainment initiatives, but the US-Australia alliance has yet to develop the type of integrated contingency planning that characterizes the US–South Korea and US–Japan alliances. Similarly, South Korea’s support for US naval maintenance, repair, and overhaul (MRO) and shipbuilding has not extended to direct South Korean participation in broader multinational operations such as freedom of navigation patrols in the Taiwan Strait. These disparities underscore the need to clarify how—and under what conditions—allied industrial capacity will be activated, enabling Washington to identify where US production must continue to remain central and where allies can best support.

Institutionalize relationships and expand joint exercises. The trilateral engagement of South Korea, the United States, and Australia has primarily taken place on the sidelines of multilateral, engagement-based initiatives, which—although this has led to some success—requires a more formalized apparatus to fully take advantage of opportunities for cooperation. Therefore, the countries should aim to build toward the institutionalization of cooperation, particularly through incremental, working-level policy initiatives. On a diplomatic level, this can include trilateral summits of ministerial-level and vice-ministerial-level officials, industry-based working groups, and other approaches. Furthermore, the three countries can build upon existing training mechanisms, such as formalizing South Korea’s role in Talisman Sabre exercises similar to Australia’s long-standing role in the Freedom Shield exercises as a key member of the United Nations Command on the Korean Peninsula. This can also provide support in building industrial cooperation. Whether to advance a more federated Indo-Pacific defense industrial ecosystem, test interoperability, or demonstrate reliability in resourcing shared collective deterrence, the United States should test allies’ capabilities during exercises in Australia and South Korea by bringing broken equipment without foreknowledge to explore allies’ regulatory environments and repair capabilities. Lessons learned and demonstrated successes would strengthen trust in allied defense and industrial capabilities, accelerating momentum toward deeper integration.

44. “Report: Declaration and Action Plan of the 1st Korea-Pacific Leaders’ Summit, 2023,” Pacific Islands Forum, May 29, 2023, https:// forumsec.org/publications/report-declaration-and-action-plan-1st-korea-pacific-leaders-summit-2023; “Fact Sheet: President Biden Unveils First-Ever Pacific Partnership Strategy,” US Embassy and Consulates in Australia, September 22, 2022, https:// au.usembassy.gov/fact-sheet-president-biden-unveils-first-ever-pacific-partnership-strategy/.

45. “2050 Strategy for the Blue Pacific Continent,” Pacific Islands Forum, 2022, https://forumsec.org/2050.

A next-generation agenda: South Korea-US-Australia

Foster expanded R&D of critical technologies. To further foster the three countries’ focus on critical and emerging technologies, trilateral and multilateral initiatives for R&D should be further expanded and facilitated. On a country-to-country level, South Korea can be added to several of the working groups in AUKUS Pillar II, allowing for collaboration on norms and governance, as well as R&D. Furthermore, institutions such as the US Defense Innovation Unit (DIU), Australia’s Next Generation Technologies Fund, and South Korea’s Defense Acquisition Program Administration (DAPA) could collaborate to provide trainings, courses, and other people-to-people collaborations to support interoperability and further stimulate the individual economies. This could also lead to a skills-based “passport” that is being discussed in the context of the AUKUS workforce and a student population that will allow for more streamlined training and formalized partnerships. Similarly, industry-led cooperation is key for furthering joint technological collaboration. Facilitating joint R&D programs and testbeds involving South Korean corporate giants, Australian tech firms, and the

US defense industry can provide opportunities that prove too sensitive for the government to tackle under the current security landscape. These initiatives can include projects such as co-developing AI-based navigation systems, as well as building secure semiconductor supply chains linking Australian critical minerals, South Korean fabrication, and US system integration.

Develop disaster-resilient infrastructure projects and early warning systems. Nontraditional security (NTS) issues provide the most practical entry points for trilateral cooperation. Unlike hard security initiatives, NTS issues cannot be solved unilaterally and are typically seen as less politically sensitive, offering responsive alternatives to China’s ambitious Belt and Road Initiative. Climate and disaster resilience stand out as the most urgent and legitimate areas for cooperation, particularly in Southeast Asia and the Pacific Islands, two of the world’s most climate-vulnerable regions. The three countries already possess institution-level linkages and expertise that can be

leveraged for joint NTS initiatives—South Korea’s Korea International Cooperation Agency and National Disaster Management Research Institute, the United States’ National Oceanic and Atmospheric Administration, and Australia’s Department of Foreign Affairs and Trade and Australian Humanitarian Partnership programs—strengthening both coordination and credibility. For example, the three countries should establish a cloud-based platform that integrates satellite, meteorological, and hydrological data to model risks such as floods, droughts, and wildfires. AI and machine learning further enhance predictive accuracy and response speed. Most importantly, this system must be connected to ASEAN mechanisms via the ASEAN Coordinating Centre for Humanitarian Assistance and the Pacific Islands Forum, ensuring local governments have access to timely information. Capacity building complements technology by standardizing responder protocols through joint academies, exchange programs for engineers, and establishing a fellowship program for the next generation of leaders and

professionals in disaster management. This approach fosters an integrated system for Southeast Asia and the Pacific Islands to enhance their preparedness while strengthening the triad’s soft power. Further, by pooling existing resources and expertise, the three countries can jointly develop guidelines for resilient infrastructure, including flood-proof housing, cyclone-resistant schools, and drought-resilient water systems. As a result, these infrastructures deliver visible community-level benefits while reinforcing the trilateral’s image as a constructive partnership.

Commentators and participants (alphabetical order)

The views and opinions expressed in this report are those of the authors, and do not necessarily reflect those of participants or the organizations with which they are affiliated.

Kester Abbott

Research associate, United States Studies Centre, University of Sydney

Afeeya Akhand

Researcher, Cyber, Technology and Security, Australian Strategic Policy Institute

Chelsie Alexandre

Policy program officer, Korea Society

Melissa Alvisi

Fellow, National Foreign Trade Council

Alex Bristow

Senior analyst, Australian Strategic Policy Institute

Ethan Chiu

Master’s in public policy candidate, Yale University

Walter Conalghi

PhD candidate, Australian National University; consultant

Jarrad Edwards

Deputy director, Navy Strategic Policy, Australian Department of Defence

Charlotte Fitzek

PhD candidate, Department of Politics, Princeton University

Matthew Fleming

Nonresident James A. Kelly Korea fellow, Pacific Forum

Markus Garlauskas

Director, Indo-Pacific Security Initiative, Atlantic Council

Lauren Gilbert

Deputy director, Indo-Pacific Security Initiative, Atlantic Council

Lindsay Hendershott

Research program manager, Stanford University

Hoover Institution

Alyssa Hirai

Master’s candidate, Georgetown University Walsh School of Foreign Service

Eleanor Hughes

Research assistant, Center for Strategic and Budgetary Assessments

A next-generation agenda: South Korea-US-Australia

Kyoko Imai

Associate director, Indo-Pacific Security Initiative, Atlantic Council

Christopher Khatouki

Postdoctoral fellow, University of New South Wales

Emily Kim

Program assistant, Indo-Pacific Security Initiative, Atlantic Council

Yoon Kyum Kim

Master’s candidate, Georgetown University Walsh School of Foreign Service

Chan Mo Ku

Legislative researcher, Republic of Korea Embassy in the United States

Christina Lee

Senior associate, Beacon Global Strategies

Dongkeun Lee

Policy fellow, Asia-Pacific Leadership Network

Jinwon Lee

Senior teaching associate, University of Hong Kong

Lynn Lee

PhD in public policy candidate, Princeton University

Yoonki Lee

Master’s in philosophy in international relations candidate, University of Oxford

Hunter Marston

Adjunct fellow, Southeast Asia Program, Center for Strategic and International Studies

Sheewon Min

Research associate, East Asia Institute

Jacob Morton

Naval officer, United States Naval Reserve

Eunju Oh

Researcher, Center for Security and Strategy, Korea Institute for Defense Analyses

James Paisley

International cyber policy analyst, US Department of Homeland Security

Jinwan Park

Nonresident fellow, European Centre for North Korean Studies

James “JB” Park

Senior fellow, Indo-Pacific Studies Center

David Phillips

Major, Air Force Global Strike Command, United States Air Force

Carita Reid

Associate research analyst, Regional, Strategies, and Policy Division, CNA Corporation

Hyunji Rim

Lecturer, School of Advanced International Studies, Johns Hopkins University

Audrey Roh

Program assistant, Indo-Pacific Security Initiative, Atlantic Council

Shawn Rostker

Research analyst, Center for Arms Control and Non-Proliferation

Tim Seguna

Postgraduate student, Australian National University National Security College

Hannah Heewon Seo

Events administrator, The Australia Institute

Hyun Chul Shim

Former staff assistant to the president for international public relations, Office of the President, Republic of Korea

Gina Sinclair

Researcher, Center for International Security and Cooperation, Stanford University

Samreen Singh

Policy analyst, Nuclear Weapons Council Support Team, Leidos (National Nuclear Security Administration)

Angie Sohn

Master’s in public policy candidate, Harvard Kennedy School

Drew Starbuck

Program analyst, Systems Planning and Analysis

David Vallance

Research associate, International Security Program, Lowy Institute

Emma Whitmyer

Senior program officer, Asia Society Policy Institute

Michaela Wong

Director, Asia policy and standards policy, Information

Technology Industry Council

Seyeon Yoo

Intern, Indo-Pacific Security Initiative, Atlantic Council

Yerin Yoon

Master’s in law and diplomacy candidate, Tufts

University Fletcher School

About the authors

Lauren D. Gilbert is the deputy director of the Atlantic Council’s Indo-Pacific Security Initiative housed within the Scowcroft Center for Strategy and Security. In this role, she oversees research and programming focused on engaging with US, allied, and partner governments and other key stakeholders to shape strategies and policies to mitigate the most important rising security challenges facing the region.

Kester Abbott is a research associate at the United States Studies Centre at the University of Sydney and a non-resident James A. Kelly Korea fellow at the Pacific Forum. He works on US Indo-Pacific strategy, defense industry issues, and Northeast Asian security dynamics, with a focus on South Korean foreign relations.

Hannah Heewon Seo is the events administrator at The Australia Institute, with a background in international affairs organizations in Australia and South Korea. Her focus centers on foreign relations and diplomacy, particularly engagement with the Asia-Pacific, and the opinions expressed do not represent those of The Australia Institute.

About the center

The Scowcroft Center for Strategy and Security works to develop sustainable, nonpartisan strategies to address the most important security challenges facing the United States and the world. The Center honors General Brent Scowcroft’s legacy of service and embodies his ethos of nonpartisan commitment to the cause of security, support for US leadership in cooperation with allies and partners, and dedicated to the mentorship of the next generation of leaders.

The Indo-Pacific Security Initiative (IPSI) informs and shapes the strategies, plans, and policies of the United States and its allies and partners to address the most important rising security challenges in the Indo-Pacific, including China’s growing threat to the international order and North Korea’s destabilizing nuclear weapons advancements. IPSI produces innovative analysis, conducts tabletop exercises, hosts public and private convenings, and engages with US, allied, and partner governments, militaries, media, other key private and public-sector stakeholders, and publics.