This article, originally published by Pacific Forum, is republished with permission.
As President Lee Jae-myung takes office in South Korea, his new government is poised to begin rebuilding domestic trust and setting forth a new foreign policy agenda.
South Korea has been in political limbo for the past six months since former president Yoon Suk Yeol briefly declared martial law in December 2024 – and in the meantime the international arena has been thrown into chaos. As South Korea reemerges into this new global context, it faces some difficult decisions about how to manage its relationships with its key economic and security partners.
Precisely because of this uncertain outlook, now is a critical time for the governments in South Korea and Japan to recommit to further strengthening their bilateral relations to deal with shared problems.
Prior to the recent period of limbo, Japan-South Korea ties had improved markedly as part of a push by former President Yoon, former Japanese Prime Minister Fumio Kishida and former US President Joe Biden to strengthen trilateral relations among their countries. Since the trilateral Camp David Summit in August 2023, over 80 US-Korea-Japan dialogues have been convened to promote collaboration in areas ranging from economics to security to people-to-people exchange.
However, with recent changes in political leadership, there are questions as to how Japan-South Korea relations will evolve in the coming months under the Shigeru Ishida and Lee administrations as the two leaders begin to engage.
Why should the governments of Japan and South Korea recommit to cooperation now? To begin with, the two governments face worsening security threats. Both Japan and South Korea harbor long-standing concerns about China, as well as about North Korea’s nuclear weapons and ballistic missile programs.
Concerns about North Korea have been compounded by deepening cooperation between Pyongyang and Moscow in the war in Ukraine and the likelihood that Russia is rewarding North Korea’s support with the transfer of military technologies.
In addition, Japan and South Korea depend heavily on an international economic order that is currently in crisis.
For years, the World Trade Organization has been stalled by disagreements among developed and developing countries and challenged by the practices of China’s state-led economic system. Now, the trade system is under immense strain as the United States imposes unilateral tariffs that undermine the “most favored nation” principle, and escalating trade war looms as a possibility.
Japan and South Korea share an interest in stabilizing the existing economic order, maintaining relatively free flow of goods and services and strengthening their own economic security and national resilience.
US ally problem: Disruption trumps stability
Moreover, Japan and South Korea must deal with a mutual US ally that is increasingly a source of disruption rather than stability.
Both countries run significant trade surpluses with the US, which has made them top targets for tariffs. Japan and South Korea currently face reciprocal tariffs of 24% and 25% respectively, as well as Section 232 tariffs on autos, auto parts, steel, and aluminum. Japanese and Korean companies are being asked to invest more in the US.
The two governments are also facing US pressure to boost their defense spending and host nation support and to increase other kinds of alliance burden-sharing at the same time as the US is considering reducing its military presence.
In general, the return of an “America First” approach to US foreign policy throws traditional alliances and institutions into question, leaving Japan and South Korea in a more vulnerable position.
How can Japan and South Korea work together to address these challenges?
The first step is to maintain the positive progress that has been achieved over the last two years.Cooperative mechanisms have been established, and plans have been set in motion to start addressing many of the common concerns mentioned previously. Some initiatives will need to be reexamined under new national leadership, but they constitute an important baseline that should not be lost.
Although the Trump administration has reaffirmed support for trilateral US-Japan-South Korea cooperation so far, Tokyo and Soul may need to push forward bilaterally without Washington in some cases.
Second, Japan and South Korea may benefit from consulting with one another regarding their respective bilateral negotiations with the US on trade and security issues. In some cases, they may even find creative ways to coordinate their efforts.
For example, SK Group Chairman Chey Tae-won recently proposed that South Korea and Japan could respond to US pressure by jointly purchasing liquefied natural gas from the US, “to increase deal size and leverage greater buying power to secure lower prices.”
This type of approach could be applied in other areas. Tokyo and Seoul could also quietly consult on their respective bottom lines, to avoid one government taking a “bad” deal with the US that sets a negative precedent for the other.
Third, Japan and South Korea can build upon the foundation of the last two years to cultivate more widespread support for improving bilateral ties among their domestic stakeholders including legislators, civil society organizations, scholars and the general public.
There have already been modest improvements in the two countries’ public sentiment toward each other, and now is the time to build on this momentum. The more stakeholders who see Japan-South Korea ties as valuable, the more resilient their relationship will be to negative episodes in the future.
There are also likely to be opportunities to build ties in the trilateral context; for example, the US House of Representatives recently introduced bipartisan legislation to establish an inter-parliamentary dialogue among elected politicians in the US, Japan and South Korea.
Fourth, Japan and South Korea will benefit from embedding their bilateral cooperation in broader regional and international coalitions.
Most of the problems that these two countries face cannot be solved through bilateral cooperation alone; instead, Tokyo and Seoul must partner with other governments in the Indo-Pacific, Europe, and elsewhere to address transnational security and economic challenges.
For example, Lee, the new president, has already announced that he will be attending the June summit of the G7, which is an important venue for South Korea to consult with other like-minded countries as a guest. Japan and South Korea can continue to strengthen their cooperation with NATO as part of the “Indo-Pacific 4.”
The two countries should also explore ways to shore up the international economic system through broader trade initiatives.
For example, they could work together to revitalize discussions on the Free Trade Area of the Asia-Pacific at the APEC summit in Gyeongju in November, and South Korea could considering joining the Comprehensive and Progressive Trans-Pacific Partnership as well as the WTO’s Multi-Party Interim Appeal Arbitration Arrangement.
Participation in such minilateral initiatives will help further reinforce and stabilize Japan-South Korea bilateral efforts.
The path ahead will not be easy. Internal politics in both countries are complex, and leaders will have to balance competing domestic and foreign policy priorities moving forward. The grievances that haunt Japan-South Korea relations cannot simply be ignored, and it will require careful, sustained effort to find mutually acceptable resolutions.
However, taking steps now to put Japan-South Korea relations on a more resilient footing will help to facilitate these difficult conversations – and the costs of not cooperating will increase if the international system becomes more unstable.
Kristi Govella (kristi.govella@nissan.ox.ac.uk) is an associate professor of Japanese politics and international relations at the University of Oxford and senior advisor and Japan chair at the Center for Strategic and International Studies (CSIS).
