What Japan’s election results mean for Seoul-Tokyo relations

Sanae Takaichi, Japan's prime minister and president of the ruling Liberal Democratic Party (LDP), places pins marking the names of candidates who won lower house elections, at LDP headquarters in Tokyo, Sunday. AP-Yonhap

On Sunday, Japanese voters delivered a decisive verdict in a snap election called just three months after Prime Minister Sanae Takaichi assumed office.

Framed as a referendum on leadership and national direction, the election produced an outcome few could ignore. Takaichi’s Liberal Democratic Party (LDP) secured a commanding share of the lower house, winning 316 of 465 seats and achieving a two-thirds majority — the largest achieved by a single party in the postwar era. With its new coalition partner, the Japan Innovation Party, the ruling bloc now has 352 seats overall. The result is a rare political consolidation for Tokyo, one that leaves Takaichi with few domestic constraints to advance her agenda.

Soo Kim

For Korea, a cursory reading of these results may prompt anxiety or hope about the election’s implications on Seoul-Tokyo relations. But this perspective shifts the focus away from the key point that Seoul now faces: Japan’s election didn’t upend the relationship so much as clarify the strategic constraints under which Seoul must now pursue bilateral relations.

In recent years, Seoul-Tokyo relations were managed more as a process than a strategy. Diplomatic caution, sequencing and incremental engagement helped keep tensions from nearing the tipping point, but they also postponed a clearer articulation of longer-term goals. With Takaichi’s political authority now consolidated, that approach may no longer be sufficient. That is, the relationship can no longer be sustained or deepened by sensitivity management alone. What matters now is whether the two countries can align their strategic intent rather than continue the relationship without a shared destination.

The central challenge in Seoul-Tokyo relations has never been a lack of rationale for cooperation, but more about Seoul’s willingness to absorb the domestic political cost to secure it. The case for strategic alignment is straightforward on paper: shared concerns about China and North Korea, deepening economic ties and trilateral cooperation with the United States. What hasn’t been clear, however, is Seoul’s readiness to prioritize long-term strategic clarity over short-term political comfort.

Takaichi’s victory brings this dilemma into sharper focus. It points not only to her appeal to Japan’s electorate or economic agenda, but also to the public’s desire for assertive leadership in a tense regional environment. Her platform combined commitments to tax reform, fiscal stimulus and a more robust defense posture, including reconsidering formerly sacrosanct restrictions on military capabilities and exports. Domestically, her conservative agenda also extends to immigration and social policy, marking a clear ideological orientation in Tokyo that Seoul must now reckon with less as a flare-up than a sustained political reality.

To be clear, Japan’s election does not alter the fundamentals of the bilateral relationship. It does, however, remove the excuses. Tokyo now has the domestic strength to pursue its priorities and will be less constrained by domestic fragility, and Seoul may no longer be able to lean on Japanese uncertainty to delay hard choices.

Seoul should be prepared to define its own priorities with similar clarity and provide answers to long-deferred questions.

The first question is what it actually seeks to achieve through its trilateral cooperation with Tokyo and Washington. Endorsing cooperation in principle is easy; sustaining it in practice is not. Trilateral alignment requires navigating domestic political sensitivities while coordinating military planning, intelligence sharing and responses to regional contingencies. Seoul, therefore, needs to be clear about which elements of trilateral cooperation are essential and which can be phased in more gradually without undermining its core interests.

Second is the sticky topic of historical disputes. Seoul must confront which disputes are operationally and strategically critical and which can be compartmentalized. Historical issues have repeatedly threatened to disrupt otherwise functional coordination between the two countries. Treating these issues as secondary, however, often backfires, leaving Korean leadership with limited leverage, not to mention lingering domestic dissatisfaction. Seoul’s challenge, therefore, is to determine which disputes must be actively negotiated and which can coexist alongside its strategic cooperation with Tokyo without undermining its credibility or public legitimacy.

Finally, Korea may also want to consider how it engages a Japan that is more politically emboldened. A partner with a strong domestic mandate can pursue its policy objectives confidently and absorb domestic political criticism. Seoul must decide how much bilateral alignment it is prepared to offer, where it needs to articulate its own priorities and how to communicate its expectations in ways that protect both security interests and domestic legitimacy. To be clear, these are questions of agency, not reaction.

History matters. It always will. But the assumption that historical sensitivities must be resolved before strategic cooperation can deepen may be a form of strategic procrastination.

Seoul needs to determine whether those disputes remain deal-breakers to the dynamic or whether they can be managed alongside cooperation on shared security and economic concerns, particularly amid greater geopolitical turbulence.

Japan’s election did not change the fundamentals of Seoul-Tokyo relations — it clarified them. For Korea, the real burden lies less in decoding Tokyo’s politics than in defining its own strategic compass.

Clarity can be uncomfortable. But in foreign policy, discomfort is often the price of agency.

Soo Kim is a former CIA analyst and strategic risk consultant.