South Korea’s new president, Lee Jae-myung, takes office facing a mountain of challenges in foreign affairs and national security — most notably, an unprecedented squeeze from Washington, where President Donald Trump’s protectionist “America First” agenda is leading to tariffs and testing the resilience of US alliances.
Lee confronts not only the persistent and existential threat from North Korea — with inter-Korean relations at rock bottom — but also the need to recalibrate the country’s diplomatic trajectory amid an intensifying US-China rivalry and an increasingly fluid global order.
But these are far from the only challenges on Lee’s plate.
Tariff battles
Front and center for the Lee administration are high-stakes tariff negotiations with the Trump administration, as sweeping US tariffs are already reshaping South Korea’s export situation and raising further uncertainty about the future of South Korea’s economy.
“The number one priority, of course, is to have an initial meeting with the (US) President," Victor Cha, Korea chair at the Center for Strategic and International Studies, said Wednesday, underscoring the importance of leader-to-leader diplomacy in tariff negotiations.
"We’ve been in a period for six months where the Trump administration has been moving at 100 miles an hour, while South Korea has basically been stuck in neutral because it hasn’t had a government. So making that first contact is very important.”
Lee also said that tariff negotiations “would become the most pressing issue we face right now,” alongside restoring people’s livelihoods and reviving the economy amid slowing growth, in an interview with local radio broadcaster CBS on Monday — the final day of campaigning.
Sectoral tariffs on cars and auto parts have taken effect, with new levies on semiconductors and pharmaceuticals looming. Aluminum and steel tariffs will double to 50 percent this week. All of these sectors are among South Korea’s key export industries, accounting for a significant share of exports to the US. Meanwhile, 25 percent country-specific reciprocal tariffs on Korean goods remain under a moratorium until July 9.
Korea pressed for bigger security role
Ramon Pacheco Pardo, professor of international relations at King’s College London, forecast that “a big bundle of issues” would be part of tariff negotiations and that “security will be part of the discussion as well.”
“South Korea will try to have other issues thrown into the mix that go far beyond tariffs and economic matters."
This broader agenda comes amid growing concerns over defense commitments. On the security front, the Trump administration has called for allies to shoulder more of the defense burden — both financially and militarily.
Anxiety flared anew over a possible reduction of around 28,500 US troops stationed in South Korea after a Wall Street Journal report in May suggested the Pentagon was considering relocating about 4,500 troops elsewhere in the Indo-Pacific, a claim the Pentagon has denied.
Both the internally classified “Interim National Defense Guidance,” reported by The Washington Post in March, and Defense Secretary Pete Hegseth’s remarks in May on the development of the 2025 National Defense Strategy underscore that US forces will prioritize deterring China.
At the same time, allies are expected to take on greater responsibility for other regional threats — in South Korea’s case, this means addressing the threat posed by North Korea, which has been recently emboldened by closer military alignment with Russia.
Retired Adm. Harry Harris, former commander of the US Indo-Pacific Command and former ambassador to South Korea, previously told The Korea Herald that he cannot rule out the possibility of a repositioning of US Forces Korea as part of the Pentagon's broader strategic realignment in the Indo-Pacific region to handle regional challenges holistically.
In Seoul, concerns are also mounting that the operational scope of US Forces Korea could extend beyond the Korean Peninsula and expand to regional defense, including being repurposed for a potential Taiwan emergency.
"In 2003, some units from US Forces Korea were redeployed to Iraq. Now, if they are redeployed — not to Iraq, but to areas near Taiwan — that could present a whole new set of challenges, and it’s something we need to think about very carefully," former Foreign Minister Yun Byung-se said during last week's Jeju Forum.
NATO summit
Another daunting task is resetting the diplomatic compass with China amid intensifying US-China competition — and with Russia, as US-Russia relations remain volatile and the Ukraine war enters a new phase.
“Lee has been pretty clear and vocal in the debates and in his statements that he wants to ‘balance out’ — I think that was the term he used — the relationship between the United States and China,” Cha said. "Lee is going to have to finesse this. There really is a hard line in the sand that the (US) administration has drawn."
Cha also warned of “negative externalities” if the Lee administration walks back too far from the previous Yoon Suk Yeol administration’s firm policy on China.
Another key and imminent decision for the new administration is whether to attend the upcoming NATO summit in The Hague on June 24–25, to which South Korea has been invited as one of four Indo-Pacific partners — Australia, Japan, South Korea and New Zealand.
Former President Yoon Suk Yeol attended three consecutive NATO summits from 2022 to 2024, where participating countries issued strong statements condemning Russia and China for their roles in the Ukraine war and voiced concern over their growing strategic alignment.
When asked whether he would consider attending the NATO summit, Lee took a noncommittal stance.
“With the domestic situation being so chaotic and complicated, unless there is a concrete agenda item, I’m not sure there is a real need to attend, so I have a lot of reservations about it,” Lee said during a news conference on May 25.
China's West Sea markers
Besides the intensifying rivalry between the US and China, another major challenge for bilateral ties with China is Beijing's unilateral installation of buoys and structures in the jointly administered West Sea zone.
Seoul has raised concerns about China’s installation of three structures within the Provisional Measures Zone — a jointly managed area established due to overlapping exclusive economic zones — between 2018 and 2024. South Korea’s Navy has also found 13 large Chinese lighthouse-style buoys, measuring 5 to 13 meters tall, installed in and around the PMZ between 2018 and 2023.
Seoul's anxiety stems from China’s past behavior both in the South China Sea and the East China Sea, including the building of artificial islands and military bases in disputed waters — often within other countries’ exclusive economic zones — causing tensions with neighboring countries such as the Philippines and Vietnam.
Unresolved JDZ between Seoul, Tokyo
On Japan ties: Despite the 60th anniversary of diplomatic normalization, the long-standing dispute over the Korea-Japan Joint Development Zone for untapped natural resources beneath the East China Sea remains a key obstacle in bilateral relations.
The agreement, enacted in 1978 for a 50-year period, can be terminated with three years’ notice, with the earliest opportunity coming in June this year.
Seoul has warned that even if the JDZ agreement is dissolved, overlapping claims —especially over Block 7 — will persist, and the issue has the potential to become a major source of tension between the two countries, particularly at this critical diplomatic juncture.
dagyumji@heraldcorp.com
