The June 3 victory of Democratic Party of Korea (DP) presidential candidate Lee Jae-myung provides South Korea with an opportunity to turn the page on six months of political dysfunction. At its core, the election was a referendum on former President Yoon Suk Yeol as well as the People Power Party (PPP), a segment of which tried to justify Yoon’s failed attempt at martial law last December. While foreign policy issues played only a small role during the snap election, the emergence of a new South Korean government has the potential to impact the US-South Korea alliance in a number of ways. Although the alliance will certainly remain intact, Washington and Seoul won’t be as in-synch as they were during Yoon’s tenure.

Yoon: A pariah at home but a darling in Washington

Yoon was an increasingly unpopular politician in the eyes of the South Korean public even before he sought to upend South Korea’s constitutional order. In April 2024, the PPP experienced a humbling defeat in legislative elections, which handed the opposition DP control of the National Assembly and effectively turned Yoon into a lame-duck. In September 2024, three months before his martial law bid, Yoon’s public approval rating was at 20%, the lowest of his presidency.

Yoon’s perception in Washington, though, was far different. The Biden administration frequently described the South Korean president as a valuable ally lauded for his cooperation on regional security matters, deterrence on the Korean Peninsula and, ironically, democratic bona-fides. In March 2024, South Korea hosted the third US-organized Summit for Democracy, where Yoon was showered with praise for leading a nation that only a few decades ago was still in the throes of a military-led dictatorship. The general perception in US policy circles was that the Yoon administration was a force-multiplier for what the United States sought to accomplish in the region and a partner that could be relied upon to keep US preferences front-of-mind.

Indeed, it was Yoon’s policy on Japan that was most appreciated in Washington. In August 2022, months after being elected by a razor-thin margin, Yoon promised to reform South Korea-Japan bilateral relations after several years of acrimony over World War II-era historical disputes and trade restrictions. Whereas former South Korean President Moon Jae-in referred to Japan in derisive terms, Yoon began talking about the country as “a partner” with shared security interests. Yoon’s commitment to resolving historical disputes with Tokyo led to a wider-ranging reconciliation; in March 2023, South Korea and Japan normalized an intelligence sharing agreement that Yoon’s predecessor, Moon, backed away from. Later that year, in August 2023, Presidents Biden, Yoon and Japanese Prime Minister Fumio Kishida pledged mutually beneficial cooperation in the fields of security, intelligence and technology. For the United States, Yoon’s diplomatic initiative took considerable political courage to pull off, and its success played into the Biden administration’s goal of creating a constellation of “minilateral” frameworks throughout the Indo-Pacific theater.

Lee’s “pragmatic” foreign policy

To the extent Lee has a foreign policy doctrine, he keeps it close to his chest. As an opposition legislator, he flirted with traditional DP-aligned views of the US-South Korea alliance, which tended to emphasize greater South Korean autonomy and a more equitable defense relationship with Washington. During his first presidential campaign in 2021, Lee was chillier on relations with Tokyo, stressing that while he would try to improve the relationship, a sincere and heartfelt apology from the Japanese over the forced labor issue was a requirement. In perhaps one of his most controversial comments at that time, Lee alleged in 2021 that the United States collaborated with pro-Japanese forces after World War II to form the modern-day Republic of Korea—remarks that sparked significant blowback.

Yet in the four years since, Lee’s foreign policy views have moved further to the center. Whether this was a campaign strategy to attract moderate voters or a true paradigm change is still unknown. Either way, Lee’s favorite word these days is “pragmatic.” Throughout this latest election cycle, he has made a concerted effort to depict himself as somebody who isn’t ideological and whose aims include balancing Seoul’s various foreign relationships. As if to underscore his pro-American credentials. Lee gave a TIME magazine interview, in part to allay whatever fears that emerged about his past positions. In it, Seoul’s military alliance with the United States was not only described as a fundamental component of South Korean foreign policy but also a crucial node in maintaining a stable balance of power in the region.

At the same time, Lee doesn’t hold much animosity toward China. Whereas the Trump administration is currently in the midst of a systemic rivalry with Beijing across multiple domains, South Korea under a Lee presidency will seek to preserve whatever flexibility and operating space Seoul has between the two superpowers. Although South Korean public opinion has soured on China lately, South Korean policymakers can’t afford to alienate the Chinese by enabling Washington’s containment policy against Beijing. After all, China is still South Korea’s largest trading partner, and the memory of the 2016-2017 THAAD incident, when Beijing slapped regulatory restrictions and tourism bans on Seoul in retaliation in retaliation for hosting a US missile defense system, is never far from the mind. Lee will face a difficult juggling act between improving relations with China on the one hand and bolstering relations with Washington on the other—the very scenario US Defense Secretary Pete Hegseth warned against during his speech at the Shangri-La security conference last week.

Finally, Seoul’s policy on North Korea is likely to change as well. Unlike Yoon, who took a hard line on Pyongyang by scrapping the 2018 inter-Korean military de-escalation accord, resuming loudspeaker broadcasts across the DMZ and treating North Korean denuclearization as a prerequisite for positive relations with the South, Lee is bound to follow the traditional DP-aligned platform. The resumption of military-to-military hot-lines and other communication channels between the two Koreas has already been broached, including during Lee’s inauguration speech, and it wouldn’t be a surprise if the new South Korean administration sought to negotiate a mutual return to the inter-Korean deescalation accord. In the grand scheme, however, the success of Lee’s North Korea policy hinges on Kim Jong Un and Donald Trump’s willingness to buy into it.

The big challenge: “Strategic flexibility”

If there is one long-term challenge that could cause the most friction between the United States and South Korea, it’s “strategic flexibility,” or the notion that US forces stationed in South Korea may be deployed to a contingency that has nothing to do with the Korean Peninsula. This is not a new dilemma in the US-South Korea alliance; during the George W. Bush administration, the two sides tried to address the issue by coming to an understanding that Seoul “respects the necessity of strategic flexibility” of US troops in South Korea and Washington “respects the ROK position” that it won’t be involved in a regional conflict that the Korean public doesn’t support.

But as US-China competition rises, US officials have become increasingly supportive of the concept. Before he was confirmed as undersecretary of defense for policy, Eldridge Colby argued that South Korea needed to take the primary role for its conventional defense against North Korea because the roughly 28,000 US troops under US Forces Korea (USFK) might need to be re-deployed to deal with a potential Taiwan conflict scenario. USFK Commander Gen. Xavier Brunson reiterated this point on May 29: “To maintain peace through strength, we sometimes have to move to other areas” He went on to state that while USFK is historically tasked with defending South Korea and preserving stability on the Korean Peninsula more broadly, the resources assigned to the command can also be made available throughout the Indo-Pacific as needed.

Although the USFK re-focusing its attention to a contingency in the South China Sea or the Taiwan Strait remains a hypothetical, the very possibility causes nerves to fray in Seoul. The concern won’t go away anytime soon and may even increase now that Lee is in power. Based on his public statements during the campaign, Lee wants nothing to do with a war over Taiwan and would prefer to maintain positive relations with Beijing and Taipei simultaneously. The Trump and Lee administrations will have to come to a more detailed consensus on the issue or risk a degradation of the alliance in the event a Chinese invasion of Taiwan becomes a reality.

Elections have consequences. A changing of the guard will inevitably bring policy change in specific areas pertaining to security and geopolitical alignment. Still, the US-South Korea alliance, now in its 72nd year, will persist.

PacNet commentaries and responses represent the views of the respective authors. Alternative viewpoints are always welcomed and encouraged.

Daniel R. DePetris ([email protected]) is a fellow at Defense Priorities.

Photo: Lee Jae Myung, the newly elected president of South Korea speaking at a press conference post-election results || Credit: Ahn Young-joon/Pool via Reuters