South Korea’s next gov't must cooperate with Japan
Published: 21 Apr. 2025, 00:04
The author is a visiting professor at Keio University and former Korean ambassador to Malaysia
The return of Donald Trump to the White House for a second term is shaking the foundations of the global order. For Korea, where a new government will take office in just two months, both domestic and external uncertainty are rapidly intensifying.
During my academic leave in Tokyo, I have had many conversations with Japanese policymakers and scholars. A recurring concern is the future of South Korea-Japan relations. “We’re worried about what will happen once South Korea’s new administration is in place,” one expert told me. While it is premature to speculate about the next government’s Japan policy, the international environment surrounding the two countries has changed significantly.
![The top diplomats of South Korea, the United States and Japan pose for a commemorative photo ahead of their meeting in about two months at the North Atlantic Treaty Organization (NATO) headquarters in Brussels, Belgium, on April 3. From left, South Korean Minister of Foreign Affairs Cho Tae-yul, U.S. Secretary of State Marco Rubio and Japanese Foreign Minister Takeshi Iwaya. [YONHAP]](https://koreajoongangdaily.joins.com/data/photo/2025/04/21/7fe1ef04-640a-41f4-8e96-a0aa6056478c.jpg)
The top diplomats of South Korea, the United States and Japan pose for a commemorative photo ahead of their meeting in about two months at the North Atlantic Treaty Organization (NATO) headquarters in Brussels, Belgium, on April 3. From left, South Korean Minister of Foreign Affairs Cho Tae-yul, U.S. Secretary of State Marco Rubio and Japanese Foreign Minister Takeshi Iwaya. [YONHAP]
There are several key reasons why cooperation between the two countries has become more urgent.
First, South Korea and Japan are now navigating a dramatically altered international order, one that requires them to act as strategic partners. Both countries face the challenge of persuading Washington to maintain its security commitments in the Indo-Pacific region. If the U.S. military presence in East Asia diminishes, as some expect, Seoul and Tokyo will be left with fewer options for ensuring their own national defense.
Should South Korea-Japan relations deteriorate at the same time, the already fragile security framework linking South Korea, the United States and Japan could weaken further. This would leave South Korea particularly vulnerable. Stronger security cooperation between South Korea and Japan is no longer optional — it is now a strategic necessity.
In trade and economics, the two countries are also being drawn together. The United States has signaled a willingness to launch broad-based tariff campaigns that affect allies as well as rivals. South Korea and Japan, both deeply integrated into global supply chains, must coordinate their responses to defend their economic interests.
Second, rising tensions in the Taiwan Strait present a shared and grave concern for both nations. China has increased military activity near Taiwan, and some media outlets have floated speculation that Beijing may consider an invasion as early as October 2025.
![A 3-D-printed miniature model depicting U.S. President Donald Trump, the Chinese flag and a fragment of the Taiwanese flag in this illustration taken on April 17. [YONHAP/REUTERS]](https://koreajoongangdaily.joins.com/data/photo/2025/04/21/e8cdd814-6329-4f4e-8c5f-c047ba26eb2b.jpg)
A 3-D-printed miniature model depicting U.S. President Donald Trump, the Chinese flag and a fragment of the Taiwanese flag in this illustration taken on April 17. [YONHAP/REUTERS]
Moreover, if China attempts to invade Taiwan, it could seek to prevent U.S. intervention by escalating tensions on the Korean Peninsula, potentially using North Korea to apply pressure. This would turn a Taiwan crisis into a broader regional conflict involving both South Korea and Japan. The time has come for the two countries to coordinate their military, technological, and economic strategies to prepare for such contingencies.
Third, other global powers are responding to Trump’s protectionist policies by exploring new frameworks for international cooperation. The European Union, for example, is pursuing stronger economic ties with both South Korea and Japan in hopes of balancing against U.S. unilateralism.
In this context, South Korea and Japan — two of Asia’s largest and most advanced economies — are indispensable. Without their participation, any meaningful response to the shifting global trade order would be incomplete. Bilateral friction between them would make cooperation with other partners more difficult and limit both countries’ ability to shape international rules and institutions.
![A combined aerial exercise by South Korea, the United States and Japan, involving U.S. B-1B strategic bombers [MINISTRY OF DEFENSE]](https://koreajoongangdaily.joins.com/data/photo/2025/04/21/c0a139af-ddfd-4a78-915c-358b49b2681f.jpg)
A combined aerial exercise by South Korea, the United States and Japan, involving U.S. B-1B strategic bombers [MINISTRY OF DEFENSE]
A stable and productive Korea-Japan relationship benefits both sides. The shifting geopolitical climate demands that Seoul and Tokyo prioritize shared interests over historical grievances or short-term political gains. Leaders in both countries must resist the temptation to use bilateral tensions for domestic advantage.
There is no viable alternative. The current moment calls for a pragmatic and forward-looking South Korea-Japan partnership — one that reflects the realities of a changing world and the mutual need for resilience.
Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.
with the Korea JoongAng Daily
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