South Korean President Lee Jae-myung faces an early foreign policy trial just two months into office, with back-to-back summits in Tokyo and Washington testing his ability to steer through Donald Trump’s unilateral push to remake postwar rules on trade, security and alliances.
The meetings follow trade deals in which Seoul and Tokyo narrowly avoided Trump’s steepest tariffs – at the cost of committing hundreds of billions of dollars in new U.S. investments.
Trump’s transactional approach has stretched beyond trade to security, stoking fears in Seoul that he may demand higher payments for hosting U.S. troops or even trim America’s military footprint in the region as he pivots attention toward China.
Those concerns mount as South Korea and Japan face deepening coordination between nuclear-armed rivals North Korea and Russia – partners in the Ukraine war and in efforts to break isolation and evade sanctions.
Here is what is at stake for U.S. allies in Asia as they deal with an America First president more unyielding than his predecessors:
A day after confirming his Aug. 25 summit with Trump, Lee’s office announced he will visit Japan on Aug. 23-24 to meet Prime Minister Shigeru Ishiba, a rare diplomatic setup that underscores how Trump is drawing closer two often-feuding neighbors with deep-rooted historical grievances.
The meeting Saturday in Tokyo between Lee and Ishiba – who last met on the sidelines of the Group of Seven summit in June – is largely about projecting leverage as the countries seek to coordinate their response to Trump, said Choi Eun-mi, an analyst at South Korea’s Asan Institute for Policy Studies.
“There is now the Trump risk,” Choi said. “There’s especially a lot of uncertainty in the business sector, so they might discuss ways to ease that uncertainty ... not necessarily in joint efforts to confront Trump, but within the framework of trilateral cooperation.”
Yukiko Fukagawa, a professor at Japan’s Waseda University, said Lee’s visit to Tokyo will also be viewed positively in Washington, long frustrated by its Asian allies’ persistent disputes over Japan’s colonial rule of Korea before the end of World War II and the way these tensions hindered three-way security collaboration.
“Because they have to deal with increasingly challenging counterparts such as China and America, both Japan and South Korea are under pressure to set aside minor differences to cooperate on larger objectives,” Fukagawa said.
Yoshimasa Hayashi, Japan’s chief Cabinet secretary, said Lee’s visit will help promote the “stable development” of bilateral ties as the countries work together on international challenges by using the “shuttle diplomacy” of regular summits.
Lee and Ishiba could discuss restarting long-stalled free trade talks and South Korea’s potential entry into the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, or CPTPP, a 12-member Asia-Pacific trade pact that Ishiba has sought to expand amid tensions over U.S. tariffs.
Ishiba, who has met Trump twice – at the White House in February and at the G7 in Canada – could also offer Lee advice ahead of his Washington summit.
Seoul and Tokyo share many crucial interests as Trump seeks to reset global trade and U.S. security commitments.
Both face pressure from Washington to pay more for the tens of thousands of American troops stationed in their countries and to increase defense spending. Their vital auto and technology industries remain vulnerable to Trump’s tariff threats.
They also must balance relations between the U.S. and its main rival, China, a growing regional threat that is also the largest trade partner for both Seoul and Tokyo. At the same time, they are alarmed by North Korea’s accelerating nuclear program and its growing alignment with Russia, which could complicate diplomatic efforts after years of stalled U.S.-led denuclearization talks.
It makes more sense for South Korea and Japan to work with the Trump administration under a trilateral framework than to engage Washington separately, especially given how Trump mixes security and economic demands, said Ban Kil-joo, a professor at South Korea’s National Diplomatic Academy.
For example, the countries could propose a trilateral scheme to support Trump’s push to expand natural gas and other energy production in Alaska, rather than negotiating investments bilaterally, Ban said.
“Beyond the drilling project itself, they would need to address security, including protecting maritime routes for the LNG shipments, and that responsibility could count toward defense cost-sharing or higher defense spending,” which Trump demands, Ban said.
Lee’s meeting with Trump could also include talks to flesh out details of South Korea’s $350 million investment fund for U.S. industries, focused on shipbuilding – a sector Trump has highlighted in relation to South Korea.
Seoul has one of the largest trade surpluses among Washington’s NATO and Indo-Pacific allies, and Trump is eager to hear from Lee how his country intends to bridge the trade gap quickly, said Victor Cha, Korea chair at the Center for Strategic and International Studies in Washington.
A more crucial topic could be the future of their decades-long military alliance, a legacy of the 1950-53 Korean War.
The U.S., which maintains about 30,000 troops in South Korea to deter the North, has long urged Seoul to allow greater flexibility in using them for missions beyond the peninsula – a demand that has intensified under Trump.
Comments by senior U.S. officials suggest that, in addition to pressing South Korea to pay more for hosting American forces, the Trump administration could seek to reshape U.S. Forces Korea as part of a broader strategy to confront China over Taiwan.
That shift would mean conventionally armed South Korea taking on more responsibility against the North, while the U.S. shifts focus to China. This could affect the size and role of U.S. Forces Korea, leaving Seoul with fewer benefits but higher costs and risks at a time when the North Korean nuclear threat is growing, experts say.
South Korean lawmakers have also expressed fears that Washington could ask Seoul to commit to intervening if a conflict breaks out in the Taiwan Strait – a difficult prospect given South Korea’s reliance on China for trade and Beijing’s role in handling North Korea.
South Korea should enter the Trump summit with a clear stance on its role in regional security, Ban said, possibly supporting U.S. efforts to maintain Indo-Pacific stability and opposing changes to the status quo without explicitly naming China as an adversary. Cha said Trump’s aides will want more explicit South Korean commitments on its approach to China.
While potentially accepting a more flexible role for U.S. Forces Korea, Seoul should also seek U.S. assurances that deterrence against North Korea will not be weakened. Any troop redeployments off the peninsula could be offset by increased airpower or the arrival of strategic assets like bombers to prevent miscalculation by the North, Ban said.
