How South Korea can balance its US commitments with global engagement

Following the impeachment and ouster of South Korean president Yoon Suk Yeol in April 2025, the election of the left-leaning Lee Jae-myung to the presidency comes at a precarious moment for South Korea. The country not only faces entrenched domestic political polarization, but it must also contend with increasingly severe security challenges from the East Asian region and beyond. Although the new government’s political position is in stark contrast to that of its conservative predecessor, President Lee has sought to pursue what he has termed a ‘pragmatic’ foreign policy, seeking to emphasize greater continuity rather than radical change.

Despite the formation of a new government, South Korea’s foreign policy is unlikely to change significantly in the short term, although the scope for change varies across foreign policy areas. At present, South Korea’s foreign policy is driven by three interlinked factors: the transactional diplomacy of the second administration of President Donald Trump and its as-of-yet unclear policy towards the Korean Peninsula; an increasingly aggressive China coupled with heightened Sino-US competition; and exacerbating security threats from North Korea. The Lee administration will have limited room for manoeuvre with respect to its foreign policies towards the US and China, which will be constrained by the long-standing US–South Korea security alliance and Beijing’s role as Seoul’s largest trading partner. Yet, partisan domestic politics will likely exert greater influence on inter-Korean relations, as has been evident in Lee’s early actions in pursuing a softer line towards North Korea compared to his predecessor. Nevertheless, Pyongyang’s lack of interest in reciprocating the Lee administration’s overtures raises the risk of North Korea exploiting South Korea’s gestures to heighten provocations.

South Korea’s foreign policy challenges will be magnified by the changing regional and global security environment. As this research paper argues, despite two recent meetings between presidents Lee and Trump, there remains uncertainty in Seoul over the degree and scope of US commitments to South Korea. At the same time, China’s ongoing efforts to engage in coercive actions against South Korea, coupled with Beijing’s assistance towards Pyongyang, continue to threaten Seoul’s security. Moreover, North Korea’s accelerated nuclear and missile programme has been accompanied both by a lack of interest in dialogue with South Korea and the US, and by ongoing security cooperation with Russia.

Despite these challenges, South Korea continues to play a growing regional and global role. Its engagement with formal and informal institutions, such as NATO, the Quadrilateral Security Dialogue (Quad), AUKUS (the Australia–UK–US defence and technology pact), as well as the Asia-Pacific Economic Cooperation (APEC) forum underscores how Seoul seeks to expand its influence beyond the Korean Peninsula. Nevertheless, these ambitions are likely to be constrained by great power politics and alliance commitments as well as, to a lesser degree, domestic political preferences.

In response to the heightened security threats facing East Asia and the wider Indo-Pacific, this research paper recommends that South Korea:

Prioritizes national interest over political partisanship. Irrespective of President Lee Jae-myung’s personal attitudes towards the US, Japan and the US–South Korea alliance, the increasing threats facing South Korea and the West’s allies in the East Asian region mean that to ensure credibility and stability, the Lee government must establish bipartisan strategies towards deterring the regional threats of North Korea and China. Such strategies must include effective sanctions enforcement, deterrence strategies and setting firm conditions for dialogue with North Korea.
Strengthens military deterrence with the US. For all the early tumult in the US–South Korea relationship following the inauguration of the second Trump administration, Seoul and Washington must focus on sustaining joint deterrence.
De-risk interactions with China. Although there is little appetite for decoupling from China within South Korea, Seoul must continue to diversify supply chains and clarify red lines on economic cooperation with Beijing, particularly with respect to sensitive technologies, including the possibility of decoupling.
Strengthens trilateralism with the US and Japan. The Lee government must not let extreme domestic political positions hinder its ability to sustain momentum from previous presidencies with respect to cooperation with Washington and Tokyo.
Deepens and broadens ties with Western partners beyond the US. By leveraging South Korea’s leading global role in maritime security, emerging technologies and cyber defence, South Korea must deepen and broaden its ties with Western partners beyond the US, whether that be Europe, NATO, or engaging with minilateral forums such as the Quad.

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How South Korea can balance its US commitments with global engagement

Dr Edward Howell

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