South Korea’s foreign policy will be influenced by three principal factors: the US’s policies towards the Korean Peninsula; heightened competition between Washington and Beijing; and the ongoing security challenges posed by a nuclear North Korea.
As Table 2 makes clear, progressive and conservative administrations in Seoul have varied in their approaches to Washington, Beijing and Pyongyang. The Lee administration has taken power at a particularly unpredictable time. Yet, South Korea’s foreign policy remains primarily motivated by three related factors: South Korea’s relationship with the US in light of the second Trump administration’s policies; intensified Sino-US economic and political competition; and escalating nuclear and military threats from North Korea coupled with Pyongyang’s lack of interest in dialogue with Seoul and Washington.
The Trump factor
As one South Korean official succinctly noted to the author, Trump ‘is a reality that cannot be avoided’. While the US president’s rhetorical disdain for what he perceives to be unequal alliances has disrupted South Korea’s confidence in its long-standing cooperation with Washington, the US continues to be the most important actor shaping South Korea’s foreign policy, a role which it has maintained since the end of the Korean War in 1953. Washington’s policies towards South Korea have also been instrumental in shaping Seoul’s approach to Beijing and Pyongyang.
While the US president’s rhetorical disdain for what he perceives to be unequal alliances has disrupted South Korea’s confidence in its long-standing cooperation with Washington, the US continues to be the most important actor shaping South Korea’s foreign policy.
Although security threats in the East Asian region have increased in severity – a situation that has dampened calls from South Korean progressives for greater autonomy from the US – the first six months of the second Trump administration saw US–South Korea relations dominated by the imposition of US tariffs on imported goods. South Korea initially faced tariffs of 25 per cent (1 per cent higher than those imposed on Japan, a competitor), which threatened industrial products such as steel, cars and semiconductors. In 2024, South Korean automotive exports to the US amounted to nearly $35 billion, which accounted for 42 per cent of South Korea’s total exports to the US and contributed to a record $55.6 billion trade surplus with Washington. After months of negotiations, US–South Korea talks saw tariffs reduced to 15 per cent in October 2025, on par with those imposed on Japan and the EU, in exchange for South Korea investing $200 billion in cash – over multiple years – together with an additional $150 billion investment in the US shipbuilding industry. Despite this agreement, Washington looks to continue pressuring Seoul to increase its own financial contributions for both the stationing of US troops in South Korea and the US commitment, under extended deterrence, to use its full military capacity, including nuclear weapons, to protect South Korea from attack.
Moving forward, US–South Korea security relations will face three principal challenges, the first of which pertains to the US Forces Korea and whether it will primarily focus on deterring North Korea or adopt a broader, regional role with respect to combating China and possibly defending Taiwan in the event of any contingency. A reduced US presence in South Korea risks emboldening North Korea, especially at a time of heightened military cooperation between Moscow and Pyongyang. Second, the US’s prioritization of deterring China risks marginalizing the regional threat posed by North Korea. As one former South Korean official stressed, this strategy could relegate North Korea to a ‘secondary concern’. Third, South Korea continues to fear both entrapment – with respect to the country being dragged into a regional conflict – and abandonment by the US. Although President Trump is yet to show any visible signs of disengaging from the East Asian region, Seoul remains aware of the possibility of a reduced US commitment to its alliance with South Korea. The recent agreement between the US and South Korea, allowing Seoul to develop nuclear-powered submarines in partnership with Washington, augurs positively for the continued US–South Korean alliance. That said, questions about the possibility of South Korea developing an independent nuclear deterrent are unlikely to subside, despite President Lee’s opposition to this possibility.
The China threat: Sino-US great power competition
In addition to the Trump administration’s lack of clarity in its policies towards the Korean Peninsula, a second challenge facing Seoul is the backdrop of escalating Sino-US competition. South Korea has long been caught between its key security ally, the US, and main economic partner, China. According to Park Jin, who served as South Korea’s foreign minister from 2022 to 2024, ‘the challenge for Korea is to find that subtle and working balance between the United States and China in a way that maximizes its geopolitical leverage.’ Yet, the Lee government comes to power at a time of acute Sino-US rivalry, spanning the domains of technology, export controls, supply chain resilience, military modernization and regional strategy. The US’s imposition of sweeping tariffs on Chinese imports is an illustration of this intense competition, despite recent talks between Trump and Xi Jinping reducing the severity of these tariffs. Trump abandoned his threatened 100 per cent tariffs on Chinese imports, due to take place from 1 November 2025, and agreed to halve the 20 per cent tariff on goods pertaining to supplies of fentanyl from China. Yet, the temporary truce in tariff talks is unlikely to lead to a thaw in Sino-US relations in the longer term.
Such heightened Sino-US competition poses clear challenges for Seoul. China notably is South Korea’s largest economic partner, with South Korean exports to China exceeding those to the US and Japan combined. Even prior to the arrival of the second Trump administration, the US had encouraged its allies and partners to diversify from China, leading to South Korea’s respective exports to the US and Japan overtaking those to China in 2023, for the first time since 2006. Nevertheless, in 2024, Beijing regained its position as Seoul’s top export destination.
Although the Lee government has hitherto decided not to enact drastic changes in South Korea’s foreign policy towards Beijing, a continuation of the status quo, for now, cannot ignore the regional and global threats posed by China. During the Biden administration, the US identified China as the main political and economic challenge to the Indo-Pacific region. The second Trump administration has continued this approach by prioritizing the deterrence of China over North Korea. Yet, this latter approach has placed South Korea in a dilemma, particularly with respect to the possibility that any broader US Forces Korea role, beyond the Korean Peninsula, will likely drag South Korea into other regional tensions, not least involving Taiwan. President Lee has explicitly asserted his intention to avoid any such scenario.
While the Lee administration has underscored how South Korea should not have to ‘choos[e] between’ the US and China, escalating Sino-US competition will render it increasingly difficult for Seoul to avoid taking sides. Both the Lee government and the president himself have outlined plans to repair South Korea–China relations from those under Yoon Suk Yeol, whom Lee deemed to have ‘unnecessarily antagonized’ Moscow and Beijing. Such rhetoric will hardly go unnoticed in Beijing, which previously criticized the Yoon government’s foreign policy postures, not least its alignment with Washington vis-à-vis Taiwan and semiconductors. From Beijing’s perspective, the Yoon government’s involvement in the ‘Chip Four’ semiconductor alliance (with the US, Japan and Taiwan) coupled with its strident support for Taiwan were responsible for worsening Sino-South Korean ties. For instance, in April 2023, China’s vice foreign minister, Sun Weidong, deemed Yoon’s description of matters pertaining to Taiwan as a ‘global issue’, akin to that of North Korea, as ‘totally unacceptable’. At the same time, any subsequent Sino-South Korean rapprochement will be constrained not only by Sino-US rivalry but the broader backdrop of deep economic interconnectedness between Washington and Beijing. For instance, on 25 August 2025, while Trump threatened to impose a 200 per cent tariff on wider Chinese exports to the US if Beijing did not guarantee Washington its supply of rare-earth magnets, subsequent Sino-US trade talks saw Beijing agree to pause export controls on rare earth minerals and magnets for one year.
Amid increasingly acute Sino-US competition, South Korea faces a dilemma typical of a middle power.
Thus, amid increasingly acute Sino-US competition, South Korea faces a dilemma typical of a middle power. On the one hand, being too close to Washington risks possible Chinese retaliation, as was most notably witnessed in Beijing’s economic and cyber response, inter alia, following the deployment of the THAAD missile system in 2017. On the other hand, leaning too closely to Beijing risks diminishing the US–South Korea alliance and losing access to cooperation in advanced technology. Nevertheless, for South Korea, maintaining stable relations between the US and China is easier said than done. Current pressures from Washington, particularly vis-à-vis limiting Chinese access to semiconductors and advanced computing chips, look to constrain any of Lee’s ambitions to tilt closer to Beijing. The critical nature of these technologies in military applications means that these pressures are indeed warranted. Any transfer of advanced technology from South Korea to China raises the risk of enhancing Chinese military, cyber and surveillance technologies, which could be used to damage the US–South Korea alliance, as well as compromise South Korea’s strategic advantage (particularly with respect to semiconductors), intellectual property and the security of Seoul and its allies.
Another complicating factor with respect to South Korea’s attempts to position itself between China and the US pertains to Seoul’s inter-Korean policy. Beijing will likely respond positively to the Lee government’s aspirations to strengthen dialogue with Pyongyang. A thaw in inter-Korean relations not only aligns with China’s desires to reduce instability along the Sino-North Korean border but provides China with greater leverage to call for a reduction in US influence over the peninsula, thereby weakening the US–South Korea alliance. Given China’s role as North Korea’s principal economic partner – and with Sino-North Korean trade now far exceeding levels prior to the COVID-19 pandemic – China will seek to exploit any reduction in inter-Korean tensions to strengthen its diplomatic and economic influence over North Korea.
At the same time, South Korea’s recently unveiled ‘123 National Agenda’, which outlines the five main objectives for the Lee government, supported by 23 strategic initiatives and 123 national tasks, made clear how South Korea seeks Chinese support in achieving North Korean denuclearization and facilitating improved inter-Korean relations. Nevertheless, the failure of past attempts by the US and South Korea to garner Chinese support for North Korea’s denuclearization, coupled with China’s continued assistance of North Korean sanctions evasion, casts doubt over Beijing’s willingness to pressure Pyongyang in this vein.
The North Korea problem
In contrast to South Korea’s relations with the US and China, the greatest effects of the change in South Korean government have hitherto been witnessed in Seoul’s inter-Korean policy. Akin to previous progressive governments, the Lee administration has prioritized reconciliation, exchange and dialogue with North Korea. The government’s five-year national strategy, outlined on 16 September 2025, seeks to revive not just inter-Korean dialogue but talks between the US and North Korea.
Given Lee’s criticisms of his predecessor’s policies towards North Korea, blaming the ‘reality’ of North Korea’s ‘cold attitude’ towards the South on the Yoon administration’s hawkish approach, it was hardly surprising that some of Lee’s earliest foreign policy steps focused on North Korea. Seoul halted loudspeaker broadcasts of K-pop and media along the inter-Korean border; dismantled loudspeakers; and suspended radio broadcasts into North Korea, the latter for the first time in over 50 years. While these measures may reduce inter-Korean hostilities in the short term and at the interactions level, they have notably severed a fundamental lifeline for the North Korean population to access outside information. Previous suspensions undertaken by South Korean governments, such as by President Moon Jae-in in 2018, noticeably exerted little influence on North Korea’s strategic behaviour.
Even though Lee’s early approach towards North Korea reflects continuity with the postures taken by his progressive predecessors, any subsequent outreach from South Korea is occurring at a time of fundamental change in North Korea’s policy towards its southern counterpart. In January 2024, Kim Jong Un announced that North Korea would no longer pursue the peaceful reunification of the Korean Peninsula under its own control, and would instead view South Korea as ‘the most hostile state’, and not part of the same – albeit divided – peninsula. Reflecting this policy shift, the Kim regime dismissed Lee’s early attempts to improve inter-Korean relations as an ‘appeasement offensive’, wherein irrespective of the government in Seoul, South Korea would remain the ‘faithful dog of the U.S.’ Thus, despite both President Lee Jae-myung and President Donald Trump seeking to revive talks with the Kim Jong Un regime, North Korea’s explicit lack of interest in doing so makes any substantive progress unlikely. Even if any such dialogue is realized, Pyongyang’s lack of enthusiasm to reciprocate Seoul’s goodwill gestures will limit the prospects of success of the Lee government’s initiatives, not least given North Korea’s increasing unwillingness to denuclearize, coupled with its ongoing egregious violations of the human rights of its people.
