This week offered two starkly different snapshots of Japan-South Korea relations. An annual joint poll found public attitudes toward each other improving in both countries. Two days later, Seoul lodged a formal protest after Tokyo’s latest defense white paper reaffirmed the country’s claim to disputed islets in the Sea of Japan.
The contrasting developments highlight a central question: Has the recent improvement in bilateral ties become durable, or is it still vulnerable to the historical and political disputes that have repeatedly pulled the relationship backward? When Lee Jae Myung first took office as South Korea’s president last June, there were concerns that the return of a progressive administration in Korea would lead to a reverse course in Japan-Korea relations.
The last progressive government under Moon Jae-in witnessed the rise of the “No Japan” campaign in South Korea, fueled by domestic politics and historical enmity.
Moon entered government after the impeachment of conservative leader Park Geun-hye, and took steps to undo the actions his predecessor had undertaken to repair ties with Japan. This included hollowing out the 2016 agreement meant to resolve the issue of comfort women—women who suffered under Japan’s military brothel system before and during World War II. Acute tension such as the “radar lock incident” that happened between the South Korean military and Japan Self Defense Force in 2018 further plunged relations into decades-old lows and witnessed public boycotts of Japanese goods and services in 2019.
The subsequent Yoon Suk Yeol administration charted a different course with Tokyo, with high-level engagements more than tripling during his first year in office. That trajectory continued throughout Yoon’s term until he was impeached following his short-lived decision to impose martial law.
Given the circumstances of Yoon’s exit and the subsequent return of South Korea’s main progressive party to power, there was a question of whether the same pattern that happened from Park to Moon would play out in the transition from Yoon to Lee.
However, Lee Jae Myung — who is widely known as a pragmatist within the ruling party — has continued bi- and multi-lateral activities with Japan, resulting in engagement across multiple levels of government. While the “drum set diplomacy” between Lee and Prime Minister Sanae Takaichi has received the most spotlight, the activities have progressed in multiple areas, including security.
Prime Minister Sanae Takaichi and South Korean President Lee Jae Myung meet in Andong, South Korea, in May.
| Pool / via REUTERS
Defense Minister Shinjiro Koizumi’s visit in June to South Korea was the first since the Park Geun-hye administration, and there have been multiple lower-level exchanges between uniformed officials that have taken place in both countries over the past year.
The momentum has also been accompanied by improving public sentiment shown in the recent joint poll conducted by the International House of Japan and the Seoul-based East Asia Institute. The poll indicated that favorable impressions of Japan among South Korean respondents increased by 1.9% since the previous year, while there was a 10.5% increase in favorable impressions of South Korea among Japanese respondents.
But Seoul’s recent protest over Japan’s defense white paper highlighted that persistent sources of enmity remain. These include issues related to comfort women, forced labor, and the disputed islets known as Takeshima in Japan and Dokdo in Korea. The Lee Jae Myung administration has avoided inflaming these issues, only resorting to pro forma protests that do not deviate from recently established baselines in the two countries’ diplomatic interactions.
Three factors help explain why the relationship has remained on its current trajectory: domestic politics, strategic considerations and generational shifts.
At home, there is little political incentive to reignite confrontation with Japan. With the political turmoil that followed Yoon’s failed martial law declaration, many South Koreans have prioritized governmental stability and economic management over historical disputes. While nationalist sentiment remains an important factor in Korean politics, it has not emerged as the defining issue of Lee’s early presidency.
The regional security environment has also shifted. The United States continues to encourage closer trilateral cooperation with Japan and South Korea, particularly in response to North Korea’s advancing weapons capabilities and China’s persistent military assertiveness. Both Seoul and Tokyo are showing that maintaining productive ties serves the broader strategic interests that extend beyond the bilateral relationship itself.
At the same time, both governments are pursuing greater security autonomy. The Takaichi administration’s push for expanding Japan’s defense posture and the Lee government’s efforts to move forward with so-called “OPCON Transition” with the United States suggest that closer cooperation is increasingly driven by converging national interests rather than solely by Washington’s encouragement.
None of this eliminates the historical sources of friction. As the recent protest revealed, territorial disputes, wartime labor and the comfort women issue remain factors in the bilateral relationship. Any one of them could once again become catalysts for diplomatic confrontation, particularly during election campaigns or periods of domestic political instability.
Yet the dynamics underpinning the relationship are no longer the same as they were a decade ago. Younger generations in South Korea have generally expressed less hostility toward Japan than their predecessors, economic and security cooperation is becoming more institutionalized, and the two governments are actively taking steps to make regular high-level engagement routine rather than ad hoc.
Whether that is enough to break the historical cycle remains an open question. But the Lee and Takaichi administrations are taking steps to advance relations in ways that can absorb friction. It may not prevent future tension, but the two governments’ current efforts are making it less likely to unravel the broader partnership when it does occur.
AloJapan.com