November 4, 2025
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.