South Korean President Lee Jae-myung said on Monday it would be "difficult" for Seoul to accept a US request for greater "flexibility" for American troops stationed in the country, a position he articulated just hours before a summit with US President Donald Trump. The concept of "flexibility" would allow US forces to adjust their positions, training, or movements without strict constraints from the South Korean side, raising concerns in Seoul about its sovereignty. Lee made the remarks to reporters aboard the plane taking him to Washington for the meeting with Trump, South Korea's Yonhap news agency reported. He said he expected the summit to cover national security issues, South Korea's defence spending, and the details of a trade agreement reached between the two countries in late July. The comments follow a statement on Friday by South Korea's top national security adviser, Wi Sung-lac, who said Seoul was reviewing plans for investment and the purchase of American weapons ahead of the presidential summit. Wi added that one of the summit's goals was to "upgrade the alliance between the two countries against the backdrop of US-China rivalry," noting that Washington and Seoul were in talks to increase South Korea's defence spending, using the NATO model as a reference. Shift in Asian diplomacy Lee's trip to Washington comes immediately after a summit in Japan with Prime Minister Shigeru Ishiba, a move thatbroke with the tradition of South Korean presidents making the US their first overseas destination. The meeting in Tokyo saw a shift in tone towards strengthening ties and a shared caution regarding President Trump's trade policies, CNN reported. Following what was described as a "historic" bilateral summit, Tokyo and Seoul issued their first joint statement in 17 years, pledging to deepen cooperation in areas such as artificial intelligence, trade, and the denuclearisation of the Korean peninsula. They also announced plans to form a joint task force to address common challenges, including ageing populations and declining birth rates. However, CNN noted that what stood out was not the agreements signed but the "mutual smiles and friendly words" between the two leaders, marking a significant change in a relationship long overshadowed by Japan's colonial occupation of Korea in the first half of the 20th century. Navigating a "volatile" Washington The recent rapprochement reflects developments beyond diplomacy, particularly what both countries see as a "volatile" relationship with Washington under Trump's "unpredictable" foreign policies. Trump has imposed tariffs, demanded increased defence spending, and pushed both countries to bear more of the costs for hosting US troops. "The problem is that Trump's mercurial, pragmatic diplomacy makes everyone nervous," Jeffrey Kingston, a professor of Asian studies at Temple University in Tokyo, told CNN. "I think a lot of America's allies are wondering, after the betrayal of Ukraine, what exactly American security guarantees mean." In Japan, Russia's invasion of Ukraine is often seen as a cautionary tale. Former Prime Minister Fumio Kishida warned: "Ukraine today may be East Asia tomorrow." Both Tokyo and Seoul are increasingly concerned about North Korea's growing nuclear arsenal and its deepening ties with Russia. Another looming concern for both Japan and South Korea is the potential for a conflict over Taiwan. Questions are being raised about whether the United States would intervene or if a future US president might seek a deal with an authoritarian leader without Taiwan being party to the negotiations, as happened at the recent Alaska summit between the US and Russian presidents. Beyond security, Trump's trade war has shaken both economies. While Japan and South Korea have signed agreements to defer tariffs, tax increases on auto parts, steel, and aluminium have hit their car and technology-reliant economies hard. At the same time, both countries must carefully manage their relationships with Beijing, their largest trading partner. Having already met Trump face-to-face, Ishiba may have offered Lee advice on how to handle the US president's style. After months of tariff pressure and growing domestic criticism, Ishiba's own tone towards Trump has shifted. "Trump is not an ordinary person," he said recently. "He is a man who changes the rules."
