On December 14, South Korea’s President Yoon Suk Yeol was suspended from his powers and duties after 204 of the 300 members of the National Assembly voted in favor of impeachment. This dramatic political development casts uncertainty over the future of his foreign policy legacy. Under the Yoon administration, Seoul had been steering its diplomacy toward closer alignment with the United States, intensifying cooperation through sanctions and joint military drills aimed at North Korea, and overcoming historical grievances with Japan to strengthen trilateral coordination that could deter China’s regional influence. This approach reshaped South Korea’s regional stance and was seen as a significant shift from previous administrations.

Domestic political turbulence, however, now raises questions about the country’s diplomatic posture not only toward its key allies—the United States and Japan—but also in its complex relationships involving North Korea, China, and Russia. The initial impeachment articles against President Yoon included claims that his administration had abandoned geopolitical balance and antagonized Pyongyang, Beijing, and Moscow, all while excessively favoring Tokyo. Such an imbalance, critics argued, risked isolating South Korea within Northeast Asia and heightened security threats. The opposition eventually removed these foreign policy-related charges from the second impeachment motion, suggesting a retreat from challenging the administration’s foreign policy through the lens of impeachment.

“In addition, under the guise of so-called value diplomacy, [President Yoon Suk-yeol] has neglected geopolitical balance, antagonizing North Korea, China, and Russia, adhering to a bizarre Japan-centered foreign policy, and appointing Japan-oriented individuals to key government positions, thereby causing isolation in Northeast Asia and triggering a crisis of war, abandoning its duty to protect national security and its people.”

Legal considerations may have influenced this shift. Foreign policy, by itself, generally does not provide sufficient grounds for impeachment unless it involves a clear violation of constitutional or legal principles. Simply making alliance decisions that some disagree with does not amount to a crime. The absence of clear evidence that foreign policy actions endangered national security or public safety makes it difficult to justify impeachment on diplomatic grounds.

U.S. analysts emphasize that South Korea’s future leadership—whoever it may be—should recognize the strategic importance of maintaining robust trilateral cooperation among Washington, Seoul, and Tokyo. Henry Haggard, former political counselor at the U.S. Embassy in Seoul, noted that this alignment is seen as crucial for confronting regional security challenges, enhancing economic ties, and demonstrating cohesive global leadership.

Yet, the turbulence following Yoon’s impeachment has reportedly caused reputational harm abroad and cast doubt on the durability of his diplomatic initiatives. There are indications that foreign counterparts, including key allies, may adopt a more cautious stance toward cooperating at senior levels out of concern that such engagement could be interpreted as endorsing a contested administration’s decisions. The resulting uncertainty raises worries about the fate of carefully cultivated alliances, especially as the regional environment grows more unpredictable. Similar concerns suggest that the political crisis could disrupt long-term strategies designed to counter North Korea’s nuclear threat and manage relations with major powers like the United States, Japan, and China. Observers note that a leadership transition following impeachment could dismantle progress achieved thus far, recalling how a similar change in government under impeachment previously led to the reversal of measures that had improved Japan–South Korea ties.

Nevertheless, South Korea’s core partners continue to affirm the underlying stability of their relationships. Then-U.S. Ambassador to South Korea Philip S. Goldberg, stated support for the country’s “democratic and constitutional process” and expressed solidarity with the Korean people. Likewise, Japanese Prime Minister Shigeru Ishiba emphasized that the importance of a Japan–South Korea–U.S. trilateral cooperation remains unaffected, despite current political turbulence.

With uncertainty surrounding South Korea’s leadership, it would be prudent for all involved parties to emphasize continuity and reassure partners. Future administrations—regardless of political affiliation—should reaffirm commitments to existing alliances, demonstrate consistency in foreign policy decision-making, and ensure that domestic political disputes do not undermine the nation’s strategic standing. By maintaining balanced diplomacy, preserving cooperation with the U.S. and Japan, and not neglecting constructive engagement where possible, Seoul can navigate this uncertain period and ultimately strengthen its position in the region.

Yujin Son is a graduate student at the Johns Hopkins School of Advanced International Studies (SAIS). She previously interned at the U.S. Embassy in Seoul in the Political-Military Affairs Unit and with United Nations organizations. Her research interests include U.S.-ROK relations, extended deterrence, and security dynamics in the Asia-Pacific region.

Disclaimer: All opinions in this article are solely those of the author and do not represent any organization.

Photo: South Korean President Yoon Suk-Yeol speaks to the nation at the Presidential Office in Seoul, South Korea. Source: Getty Images