The new direction of U.S. foreign policy under the second Trump administration is currently shaking up the international security order, centered on the war in Ukraine. The Europe-U.S. security alliance, which had been based on countering Russian aggression within a values-based international order, has begun to erode as Trump moves toward positive negotiations with Russia within a more power-based structure of international relations. The growing tension in the transatlantic relationship has sparked a crisis that has significantly impacted South Korean diplomacy.
South Korea’s position on the war in Ukraine has been consistent since it began. Based on its values-driven advocacy for “liberal democracy,” part of the vision of making South Korea a Global Pivotal State, Seoul has expressed its firm support and solidarity for Ukraine and continued to provide active humanitarian assistance and reconstruction support. In particular, as part of this diplomacy, South Korea emphasized cooperation with “like-minded states” that share universal values. Previously, this meant aligning with the United States under the Biden administration’s emphasis on rebuilding a “values-based international order” – the same goal that also underpins the EU’s foreign policy. This has led to the emergence of the partnership between NATO and the IP4 (Indo-Pacific Four: Australia, Japan, New Zealand, and South Korea), reflecting a strategic alignment of shared values and interests.
However, with the new Trump administration seeking to shape international order through a power shift, this values-based alliance has been undermined. Amid this erosion of international order, South Korea’s diplomatic and security moves have been significantly indecisive. This was reflected at the U.N. General Assembly and Security Council voting on February 24, on the third anniversary of Russia’s full-scale invasion of Ukraine. At the U.N. General Assembly, South Korea voted in favor of an EU- and Ukraine-led resolution condemning Russian aggression and supporting Ukraine’s territorial integrity, but at the U.N. Security Council (where South Korea is currently a non-permanent member) Seoul also voted in favor of a U.S. resolution calling for an end to the “conflict,” which did not include any criticism of Russia. Notably, Ukraine’s other major supporters on the UNSC – Denmark, France, Greece, Slovenia, and United Kingdom – all abstained from the U.S.-sponsored resolution.
Regarding the vote, a South Korean Ministry of Foreign Affairs official explained, “Although the U.S. resolution in the Security Council did not include the amendments we supported, it implored for the early cessation of the Ukraine war, which is a major global issue, and thus does not conflict with our position. Moreover, considering the need to garner international support and resolve the conflict, we supported it.” The official further stated, “The importance of close coordination between the U.S. and South Korea on issues such as the U.S.-South Korea alliance and the North Korean problem was also comprehensively taken into account.”
The U.N. voting was just one example. Overall, South Korea is navigating a turbulent and uncertain diplomatic path between the U.S. and EU. South Korea and the United States have a long-standing and strong security alliance, and since gaining independence South Korea has always prioritized the alliance in its security concerns. The alliance with the U.S., especially as a geopolitical actor directly involved in the Korean Peninsula, has continued to be at the core of South Korea’s diplomacy.
On the other hand, South Korea and the EU have been strengthening their strategic partnership. They signed the “Security and Defense Partnership” in November 2024 to enhance cooperation in areas such as maritime security, cyber, disarmament and non-proliferation, and defense, deepening their alliance by extending an order based on values and international rules into the security sphere. Under the previous administration, this effort was supported by the United States and indeed complemented the South Korea-U.S. alliance. That is no longer the case under the Trump administration.
In the shifting dynamics of the international order, South Korea confronts the challenge of balancing its traditional alliance with the U.S., cantered on conventional security concerns, while strengthening its ties with the EU through a new security approach grounded in shared values. This situation underscores South Korea’s broader dilemma as a “middle power” in international relations, seeking cooperation with major powers while conducting diplomacy that avoids conflicts between allies. Moreover, South Korea, which is on a geopolitical fault line, will continue to strive to secure this diplomatic flexibility in the midst of the crisis of the reshaping international order, especially with the possible emergence of a system that prioritizes a balance of power. Under these circumstances, Seoul will no longer attempt to alter the status quo by leaning noticeably to one side or the other but will adopt the main behavioral pattern of a middle power in order to best defend its national interests.