Rough Seas Ahead for Japan-Korea Ties After Yoon’s Martial Law Muddle?

A Freeze in Korean Foreign Policy

At 10:30 in the evening on December 3, South Korean President Yoon Suk Yeol called a sudden press conference at which he declared martial law had gone into effect. Korean military forces were dispatched soon afterward to the National Assembly building and the National Election Commission headquarters; a ban on political activities went into effect and restrictions were placed on media coverage. The dramatic development was over in just six hours or so, though, as lawmakers managed to overcome the military blockade—in part thanks to what was effectively “sabotage” of the martial law restrictions on the part of soldiers—and assemble to pass an emergency bill calling off the president’s declaration.

This did not mean an end to the turmoil in South Korea, though. The opposition parties, which collectively hold a majority of seats in the legislature, immediately launched impeachment procedures against the president, while the nation’s police, prosecutors, and Corruption Investigation Office for High-ranking Officials began investigating whether Yoon had committed criminal acts aimed at fomenting domestic disorder. Massive public demonstrations took place in various parts of the country, and as officials including the former minister of defense were arrested one after another, on December 14 the National Assembly passed a motion to impeach President Yoon in its second attempt to do so. This put an end to his authority as president.

This chaotic situation has naturally had a significant impact on Korea’s relationships with other nations. With Yoon effectively out of power and Prime Minister Han Duck-soo serving as acting president in his stead, Seoul’s foreign-relations apparatus is no longer functional.

South Korean President Yoon Suk Yeol bows his head during a December 12 speech in Seoul, in which he pledged he would “fight until the last moment” and sought to justify his actions in declaring martial law on December 3. (Courtesy of the ROK Office of the President; © AFP/Jiji)

There are several reasons for this. First, the prime minister is a political appointee chosen by the president; while this person can be selected from among the legislature’s membership, Han was not elected to office and is seen as lacking legitimacy as a result. Second, Han himself is not unconnected to the martial law debacle, having been part of the State Council meeting immediately prior to its declaration; while he states that he and the other cabinet members opposed Yoon’s decision, he is still a target for accusations here. And third, the ruling People Power Party, which ordinarily could be expected to support the acting president in his activities, is currently in a shambles. After multiple members went against the official party line and voted in favor of impeachment on December 14, a steady stream of party officials have announced their resignations, and party leader Han Dong-hoon stepped down on December 16.

All of this means that further turmoil is expected in Korean politics, making it unlikely that the acting president will feel empowered to make meaningful moves on the international stage. And as US President-elect Donald Trump prepares to return to the White House in January 2025, significant delays are also expected in Seoul’s moves to establish a solid relationship with his incoming administration.

Japan-Korea Ties Set to Backtrack

Let us look then beyond this interim presidency under Prime Minister Han Duck-soo. As the stage is set now, it seems almost certain that Korea’s Constitutional Court will sign off on the impeachment and dismiss Yoon from office, and the ruling PPP is equally certain to face severe headwinds in the presidential election that would follow such a decision. The leader in the running for the next president of South Korea is Lee Jae-myung, who heads the opposition Democratic Party, but he too is weighed down by plenty of baggage, including a November 2024 conviction for violations of the Public Official Election Act. With his own fair share of detractors, there is no guarantee that he can successfully navigate a presidential election.

Rather than considering who will lead Korea next, it may be more instructive to think about how the present circumstances are likely to impact the new president’s policy choices. Here we must note that with President Yoon having been impeached for his tumultuous declaration of martial law, much of what he accomplished since being elected in 2022 will now be viewed in a much harsher light. In particular, the concessions he has made to Japan in connection with issues of historical perception—such as his moves to find a bilateral solution to the question of Japanese companies’ compensation for Korean laborers forced to work for them during the colonial and wartime eras—are already viewed negatively by the Korean public. Even if the ruling PPP manages to hold on to power, chances are slim that this approach will be allowed to stand. The outcome will be a return of the history issue to the frostier state where it was toward the end of the 2017–22 administration of President Moon Jae-in.

Turning next to regional security issues, it is worth noting that unlike the relatively static area of historical recognition problems, the surrounding security environment has seen considerable shifts in the years since Moon was in office. In particular, since Russia invaded Ukraine in February 2022, despite broad international condemnation of Moscow, China and North Korea have declared clear support for the Russian campaign, with Pyongyang going so far as to send troops to fight on the Russian side. In this environment, it will not be easy for a new administration in Seoul to seek to restore channels of dialogue with the North Koreans, as President Moon did, or to pursue closer economic ties with China in the pattern of President Park Geun-hye (2013–17).

There are still other factors constricting the choices available to the next Korean administration. In the United States, Donald Trump has clearly signaled his intent to apply punishing tariffs to imports from China, leading to heightened risks for Korean firms considering fresh investment in their giant neighbor. Meanwhile, the Chinese economy itself is showing signs of slowing, and the rate of Korean economic dependency on China has shown almost no growth for a decade. Compared with 2013, when President Park took office, Korean sentiment toward China has soured considerably, with views that were once hopeful for the future now increasingly pessimistic.

Demonstrators in front of the National Assembly in Seoul celebrate passage of the motion to impeach President Yoon on December 14, 2024. © Lee Young Ho/Sipa USA; via Reuters Connect)

A Declining US Presence in East Asia?

North Korea, meanwhile, has since the end of 2023 repeatedly declared that it no longer seeks to reunify with the South, in a departure from its previous stance. Whereas we might once have expected North Korea to swiftly make hay of the turmoil in Seoul following Yoon’s martial law declaration, this time its response has been remarkably slow, with a full week passing before Pyongyang released a statement on the situation south of the border. What is more, that statement was not the sort of bombastic criticism and calls for reunification once common, but rather a straightforward presentation of the North Korean take on the ongoing developments.

This signifies that North Korea is losing its expectations of and interest in progressive forces in South Korea as a target for its promotion of reunification. In this, it seems to have learned a lesson from the gap between the advances in North-South dialogue seen during the first part of President Moon Jae-in’s administration and the stagnation seen in its latter period. It has been pointed out that the favorable views and positive expectations of South Korea seen in the North while ties were growing warmer led also to heightened dissatisfaction among the North Korean people with their own regime; even if the next South Korean government skews more to the progressive side and seeks to rekindle cross-border dialogue, Pyongyang may well respond coolly this time.

The upshot is that the next South Korean president will have few options when it comes to the country’s security policy moving forward. It will be difficult to depart from the current diplomatic course, centered firmly on Korea’s alliance with the United States. We can therefore expect to see little change in the country’s international position in the time to come.

We may see the following scenario play out once a new president takes the reins in Seoul. While remaining dedicated to strong ties with Washington in its foreign policy stance, there will also be a worsening in its relationship with Japan, due to historical perception issues, despite 2025 being the milestone sixtieth year since the 1965 normalization of bilateral ties. Japan, too, is unlikely to depart from its security policy built around its alliance with the United States, which means we could see a return to the dynamic seen in the days of President Park and Prime Minister Abe Shinzō (2012–20), when Tokyo and Seoul vied with one another for American favor.

One factor differs considerably today from that era, though: the fact that Donald Trump, not Barack Obama, occupies the White House. President Obama recognized the importance of American ties with both sides, and his hard work on the diplomatic front culminated in the 2015 “comfort women agreement” between Tokyo and Seoul. Now, though, with an isolationist Trump in the Oval Office, America has fewer incentives to maintain solid ties with its allies in East Asia—and indeed, may even see growing friction between Japan and Korea as a perfect excuse to draw down its involvement in the region.

With a new administration on the way in Washington and turmoil continuing in Seoul, Tokyo—even with its minority government in power following the Liberal Democratic Party’s losses in the October general election—comes across as having the most governmental stability of the three. After President Trump pulled the United States out of the Trans-Pacific Partnership during his first term, it was Japan that pulled together its remaining members and solidified the pact. As the global environment remains shaky, we may be entering an era when the world looks to Japan for real leadership once more.

(Originally published in Japanese on December 19, 2024. Banner photo: South Korean troops head toward the National Assembly building in Seoul on December 4, following President Yoon Suk Yeol’s emergency declaration of martial law in the late hours of the previous day. © Kyōdō.)