The South Korea-US alliance has faced a year of uncertainty in trade, security, and geopolitics since US President Donald Trump's return to the White House, but hard-fought bilateral deals have provided a more stable footing. Following President Lee Jae Myung's election, summits between the leaders led to a joint fact sheet on agreements, contributing to relationship stability. Challenges like tariff uncertainties and security issues remain.
US President Donald Trump's second nonconsecutive term began on January 20, 2026, ushering in uncertainty for the South Korea-US alliance amid South Korea's political turmoil following former President Yoon Suk Yeol's failed martial law bid, impeachment in December 2024, and ouster in April 2025. Newly elected President Lee Jae Myung in June 2025 pledged to center the US alliance in his "pragmatic" diplomacy, alleviating Washington concerns of a tilt toward China.
To address delays from Seoul's transition, summits occurred: the first at the White House in August 2025 and the second in South Korea in late October ahead of the APEC summit. A November joint fact sheet, the first official document between the administrations, outlined agreements including Seoul's $350 billion US investment pledge in exchange for reducing "reciprocal" tariffs on South Korea from 25% to 15%. Trump announced these tariffs on April 2, 2025—dubbed "Liberation Day"—to address trade deficits and boost manufacturing. However, uncertainty lingers as the US Supreme Court may rule soon on the legality of his emergency powers use; if unfavorable, alternative measures are expected, potentially pressuring Lee's investment commitment domestically.
Geopolitically, a White House official voiced concerns over "Chinese interference and influence," urging Seoul to distance from Beijing amid US-China rivalry. Lee's administration emphasized the alliance as central to its policy and supported trilateral ties with Tokyo. A low point came in September 2025 when ICE raided a Korean battery plant site in Georgia, detaining over 300 workers—deemed the largest single-site operation in Homeland Security history—for illegal work on visas. Released after a week, the incident sparked outrage in South Korea. US Deputy Secretary of State Christopher Landau expressed regrets and committed to visa fixes, leading to a bilateral working group and a special embassy desk in Seoul.
Security modernization aims to boost Seoul's defense spending and responsibilities, allowing US forces to address broader threats like China. Speculation surrounds expanding the 28,500-strong US Forces Korea (USFK) role beyond the peninsula, possibly shifting to stronger air and naval components. November's defense talks communique omitted the usual commitment to current USFK levels, fueling drawdown worries; discussions will accelerate post-Pentagon's National Defense Strategy release.
Trump approved South Korea's nuclear-powered submarine project after the second summit, countering proliferation fears and eyeing utility against China, though US procedures complicate timelines. The US backed Seoul's uranium enrichment and spent fuel reprocessing for civilian use in the fact sheet. On wartime operational control (OPCON) transfer, November talks in Seoul between Defense Minister Ahn Gyu-back and Secretary Pete Hegseth agreed to expedite a roadmap for handover by 2030 under conditions like South Korea's command capabilities and regional stability. OPCON was ceded to UN Command in the 1950-53 Korean War, moved to Combined Forces Command in 1978; peacetime control returned in 1994, wartime remains with the US.
Both administrations hope to resume North Korea diplomacy, despite Pyongyang's disinterest amid Russian aid reliance. Lee pledged during the first summit that Seoul would act as a "pacemaker" for Trump's "peacemaker" role. Speculation suggests Trump may revive personal ties with Kim Jong-un in April 2026 during a China visit with Xi Jinping. With groundwork laid, the allies aim to implement trade, investment, and security pacts.
