South Korea's President Lee Jae-myung speaks during a press conference at the Presidential office in Seoul on June 4, 2025. PHOTO: AFP
TOKYO/CHONGQING – South Korea’s East Asian neighbours Japan and China on June 4 quickly congratulated President Lee Jae-myung on his resounding election win, even as both countries watch closely for clues to how the liberal leader will approach bilateral relations.
This scrutiny stems from perceptions that South Korean diplomacy oscillates wildly, depending on the ruling party of the day. Liberals are judged to be hostile towards Japan and friendly towards China and North Korea, while conservatives hold an opposite view.
Ties between Tokyo and Seoul plunged into a deep freeze under the previous liberal president Moon Jae-in, only to thaw rapidly under Mr Lee’s ousted predecessor, Yoon Suk Yeol, who is now facing insurrection charges for his martial law debacle.
Mr Lee had previously described Japan as an “enemy nation” and went on a 24-day hunger strike to oppose Yoon’s conciliatory policies, which he termed “humiliating diplomacy”. He has also criticised Yoon for worsening ties with China by moving closer to the United States on positions such as Taiwan, which Beijing regards as part of its territory to be reunited with.
But Mr Lee adopted a more centrist agenda on the campaign trail, saying that he wanted to repair fraying ties with China, while also insisting that he held a “very favourable impression of the Japanese people”.
His approach to this diplomatic tightrope will have ramifications from Washington to Tokyo, as the US corrals its Indo-Pacific allies for support in its big-power competition with China. Both Japan and South Korea are US security allies, while China is their largest trading partner.
On June 4, Mr Lee said: “I will strengthen cooperation between South Korea, the US and Japan, based on the solid South Korea-US alliance, and will approach relations with neighbouring countries from the perspective of national interest and practicality.”
All eyes will be on Mr Lee’s likely diplomatic debut on June 15 at the Group of Seven summit in Canada, where South Korea has been invited as an observer. There, he could potentially meet bilaterally with US and Japanese leaders.
Amid the diplomatic ambiguity, analysts in China were sanguine about Beijing-Seoul ties, while Japanese observers were more circumspect over bilateral relations.
In a congratulatory message to Mr Lee, Chinese President Xi Jinping stressed that he attaches “great importance” to China-South Korea relations.
The two countries, he said, are close neighbours and partners that have overcome ideological and social differences in the 33 years since establishing diplomatic ties to develop stable and healthy relations.
This partnership “not only improved the well-being of the citizens in both countries, but also promoted regional peace and stability”, Mr Xi added, according to state media reports.
“China is willing to work with South Korea to adhere to the original intention of the establishment of diplomatic ties and firmly follow the rules of good neighbourliness and friendship,” Mr Xi said, noting that this is to the benefit of both countries at a time of growing regional and international uncertainty.
Over in Tokyo, Japanese Prime Minister Shigeru Ishiba delivered a similar message of working together as “partners” and close neighbours to tackle global challenges, as the countries celebrate the 60th anniversary of bilateral ties in 2025.
“The importance of holding summit talks at an early date and engaging in ‘shuttle diplomacy’ won’t change,” Mr Ishiba said, referring to the practice of the leaders regularly visiting each other’s countries, while expressing his hopes to “further invigorate bilateral exchanges” at all levels.
Yet, Japanese officials are wary that Mr Lee’s election will portend a dramatic shift in bilateral ties, given that he has said he would broach wartime issues over Japan’s colonial rule of the Korean peninsula from 1910 to 1945, and the territorial dispute over the Dokdo/Takeshima islets.
This is especially since 2025 marks the 80th year since Japan’s wartime surrender, an anniversary year that could be weaponised to stoke tensions by raising historical grievances.
Japan’s position is that all wartime reparations have been “completely and finally” settled under a 1965 agreement to normalise ties, with Tokyo paying US$500 million (worth about US$5 billion today, or S$6.4 billion) in grants and low-interest long-term loans to South Korea.
But past South Korean administrations have repeatedly brought up historical issues, including comfort women and wartime labour, casting a pall over bilateral relations.
“Even if the administration takes a conciliatory stance towards Japan at the start, it could gradually evolve into a hardline stance towards Japan,” a Japanese Foreign Ministry official was quoted as telling the Mainichi newspaper.
Another official was cautiously optimistic, saying it would be foolhardy to stoke anti-Japan sentiment at this time, given the positive public opinion. North Korea’s military involvement in Russia’s invasion of Ukraine also means that geopolitical calculations would have changed, the official was cited as saying.
Kobe University’s Professor Kan Kimura told The Straits Times that the way forward is unpredictable, given that invoking history would be a non-starter for Japan.
“Lee’s language over history and territorial disputes is going to be provocative,” he said. “The question is whether both countries can delink history with economic and security issues.”
He saw it in Seoul’s interests to maintain close ties with Tokyo, saying: “Given that South Korean public opinion towards China is worsening, North Korea is refusing to engage in dialogue with South Korea, and the US is exerting pressure including through tariffs, objectively speaking, South Korea has almost no diplomatic options.”
Analysts in China told ST that ties will likely thaw between Beijing and Seoul under Mr Lee, whom they expect will strike a better balance amid US-China competition.
Associate Professor Zhang Guangxin at Zhejiang Gongshang University’s East Asian Institute in Hangzhou noted that despite Yoon’s pivot to the US that had chilled bilateral relations with China, trade between the two countries remains robust.
Exports from South Korea to China grew 6.6 per cent in 2024 from the year before, which underscores the robust trade relations, Prof Zhang noted.
“Mr Lee’s clear victory over the People Power Party (which Yoon belonged to) shows the South Korean public’s desire for economic stability,” he said.
Associate Professor Kim Chang Hyun of the China Europe International Business School in Shanghai, meanwhile, said business elites in South Korea no longer see China solely as a big market for their products but also as “an important partner to learn from”, pointing to China’s advances in green technology and artificial intelligence.
The two experts said that public opinion in South Korea towards the US is likely deteriorating, given US President Donald Trump’s demands that Seoul pay more for defence, and the threat of “reciprocal tariffs” of 25 per cent.
Students from South Korea – the third-largest source of foreign students to the US – are also facing heightened uncertainty over Mr Trump’s immigration policies.
“There will be some rebalancing in public opinion in South Korea towards the US now,” Prof Kim said.
Asia News Network/The Straits Times
