South Korean diplomacy: the wheels are coming off
Since President Lee Jae Myung entered office in June 2025, I have mostly complimented his administration’s foreign policy. Alas, the wheels are coming off. Before we get to the current situation — with Seoul flailing on U.S., Ukraine and North Korea issues — let’s review the trajectory until now.
When Lee took office, he faced a difficult diplomatic environment. Above all, Seoul was under competing pressures from Washington and Beijing. The U.S. under President Donald Trump was increasingly demanding of allies — including Seoul — in the realms of security and economics. Meanwhile China remained a tricky economic partner for South Korean industry and a regional security actor with inscrutable goals on North Korea. Upgrading other bilateral relations was important, both per se and as means for creating more autonomy vis-à-vis the U.S. and China. To this end, Seoul continued to enhance strategic partnerships — e.g., with Japan, Europe, Australia, Singapore and Canada — while emphasizing relations with Global South states with significant commercial or resource profiles.
An important multilateral diplomatic calendar also loomed — a mid-June G7 summit, late-June NATO summit, September U.N. General Assembly, October APEC summit hosted in Gyeongju and December G20 meeting.
The Lee administration largely acquitted itself well, notably on key bilateral issues and the APEC summit. South Korea stood firm as a U.S. ally while patiently resisting excessive U.S. trade and investment demands. Seoul’s trade relations with Beijing stayed on track, and China even removed controversial facilities from the China-South Korea Provisional Maritime Zone. Entente with Japan continued apace, to the surprise of many, given the contentious history of Seoul-Tokyo relations under prior progressive presidents. Outreach to other strategic partners and the Global South established a conveyor belt of memoranda of understanding on economic relations, supply chains, critical resources and other cooperation areas that may mitigate some of the risks Seoul experiences in being caught between Washington and Beijing.
APEC in Gyeongju was successful, both multilaterally and in terms of bilateral meetings surrounding it. The most important was a Trump-Lee summit that — in principle — established a U.S-South Korea trade and investment agreement and opened the door to a South Korean nuclear-powered submarine deal that includes potential rights for Seoul to develop uranium enrichment and spent nuclear fuel reprocessing capabilities.
However, the end of 2025 marked the high point of Lee’s diplomacy, and it has been mostly a downhill slide ever since. In January 2026, the Trump administration began voicing displeasure at Seoul’s implementation of the trade and investment deal. In January and February, U.S.-South Korea discord over the treatment of online delivery platform Coupang began disrupting progress in other areas, including security and defense. Also in February a kerfuffle emerged over the scheduling of U.S.-South Korea-Japan trilateral air exercises. Spring and summer were marked by the effect of the U.S. war against Iran, which both affected South Korea’s economy and occasioned Trump to coerce Lee into joining the war. This reached a climax with an angry social media post in which Trump insulted Lee and South Korea, praised North Korean leader Kim Jong-un, curtailed U.S.-South Korea military exercises and again pressured Seoul to enter the Iran conflict. All this was accompanied by growing influence of the “autonomy” faction of South Korea’s progressive foreign policy apparatus, which began to crank up obsequious, ineffective outreach to Pyongyang. They also added a wrinkle by attempting — for reasons involving commercial relations, natural resources, arctic shipping and North Korea — to get the Lee administration to accommodate Putin’s Russia, thus irritating European and Canadian partners.
Currently the diplomatic wheels are off the rails. Washington and Seoul publicly dispute the status of South Korean investment into an Alaska LNG project — a deliverable for the U.S.-South Korea trade and investment deal. Consequently Trump is threatening to punish Seoul financially. The submarine deal may also be endangered. The transfer to South Korea of North Korean POWs held by Ukraine has devolved into a rhetorical fight between Seoul and Kyiv over whether the POWs’ repatriation should have been announced. Regardless of which side is right, Seoul would have been better served to keep the argument quiet. A North Korean land mine that exploded in the DMZ, injuring South Korean soldiers, has backfooted Lee’s administration. In demanding a North Korean apology while also downplaying the incident as an “unfortunate accident,” Seoul is incoherently both making it a big deal and providing Pyongyang with cover. Unsurprisingly, the media report that the National Security Council’s “autonomy” and “alliance” factions are deeply divided over the response.
How did Lee’s diplomacy go from hero to zero? Beyond intra-government ideological rifts, domestic politics play a role. Lee’s weakened poll numbers are causing ruling party frustration, with the “autonomy” faction using increased influence to underline South Korean sovereignty as an appeal to base supporters of the Democratic Party of Korea.
This probably won’t work domestically. It’s definitely failing diplomatically. The next risk is that the administration doubles down and gins ups problems with Japan. In that case, the train will likely be not only off the rails, but over the cliff.
Mason Richey is a professor of international politics at Hankuk University of Foreign Studies and president of the Korea International Studies Association.