Turbulence in Seoul: The Aftermath of Political Upheaval

On April 4, 2025, four arduous months following the abrupt declaration of martial law on December 3, 2024, South Korea’s Constitutional Court unanimously ruled to remove President Yoon Suk Yeol from office. His miscalculated decision, which revived the specter of authoritarianism –  a trauma embedded in the nation’s collective memory since 1980 –  sent shockwaves across the nation and the world. Although the National Assembly swiftly rescinded the martial law order within three hours, the fallout was profound and lasting. By January 14, 2025, Yoon faced charges of “insurrection,” marking a stark escalation, deepening domestic unrest, and casting a shadow of uncertainty over the future of East Asian geopolitics. As mandated by the Constitution, a new presidential election must occur within 60 days of Yoon’s removal, setting June 3rd as the latest possible date. In the interim, Prime Minister Han Duck-Soo – a fellow member of Yoon’s conservative People Power Party (PPP) – will continue to serve as the acting president, steering the nation through these turbulent times. Can a fractured South Korea hold back East Asia’s brewing storm, or will Seoul’s turmoil expose East Asia’s deepening fault lines? 

As a former star prosecutor, Yoon was fully aware of his country’s dark and haunting history with military dictatorships and coups. His decision, therefore, is perplexing. Declaring martial law severely restricts civil liberties, including the freedom of speech, publication, assembly, and association. Why take such a drastic step? The true motivations behind his actions remain shrouded in ambiguity. However, Yoon justified his decision by alleging that the opposition party, the Democratic Party (DP), sought to subvert the nation’s democratic framework. Yoon further alleged that the DP was collaborating with foreign adversaries, notably communist forces from North Korea and China. Yoon framed his actions as necessary measures to protect South Korea from what he described as urgent and destabilizing threats, accusing these so-called “antistate forces” of purportedly undermining the country. Furthermore, Yoon asserted that such extreme measures were critical to prevent South Korea from collapsing and to safeguard its sovereignty. Nevertheless, critics argue that Yoon’s actions were rooted in escalating tensions with the opposition-controlled National Assembly. After the DP’s “landslide victory” in the 2024 parliamentary elections, they frequently obstructed the legislative agenda of Yoon and the ruling PPP. Many analysts view the declaration of martial law not as a response to external threats, but as a political maneuver amid deepening domestic confrontation. 

Shifting Sands: Political Fallout

The entrenched polarization within South Korea not only underscores the political climate but also sets the stage for major governance challenges. In recent years, widening ideological divisions have undermined the government’s ability and efforts to address pressing domestic concerns – from labor market reform to social welfare expansion. Diplomatic initiatives requiring bipartisan consensus often faltered, stalled, or were diluted by opposition. The impeachment of President Yoon intensified the already deep-seated political polarization, laying bare a society fractured by partisanship. The controversy surrounding his martial law declaration galvanized both supporters and opponents, who filled the streets surrounding the Constitutional Court. As political discourse became increasingly polarized, the impeachment emerged as both a legal rebuke and a broader reflection on the state of South Korean democracy. It triggered ongoing debates over governance, accountability, and the rule of law in an era of democratic fragility. 

With presidential primaries fast approaching, attention now shifts to the upcoming election. Former DP leader Lee Jae-Myung, who narrowly lost to Yoon in 2022, leads with an approval rating of 34 percent, the highest among other potential candidates. Though his candidacy carries weight, his political career is marred by allegations of the misuse of power and corruption, including the illegal transfer of $8 million to North Korea. While these scandals could cloud his potential presidency, the scale of Yoon’s political collapse may overshadow Lee’s controversies. For many voters, restoring democratic norms and stability may take precedence over holding Lee accountable. Meanwhile, the PPP’s prospective candidates face an uphill battle. Labor Minister Kim Moon-Soo and former PPP leader Han Dong-Hoon hold approval ratings of just 9% and 5%, respectively. Yoon’s political implosion – deemed by some as political suicide – has severely damaged the party’s image. Once heralding a vision of South Korea as a “global pivotal state,” the PPP championed closer ties with the US and Japan through economic and security cooperation. Yet, Yoon’s martial law declaration and subsequent impeachment severely tarnished the party’s credibility and future prospective candidates. In contrast, the DP is gaining momentum. With a more nationalist stance, the party is critical of military reliance on the US and maintains strong anti-Japanese sentiment, a sharp departure from the PPP’s more open positions. As the political balance shifts, South Korea stands at a critical juncture. 

A Nuclear Crossroads: Divergent Visions of Deterrence

Amid this political uncertainty, the debate over nuclear proliferation has reemerged as one of South Korea’s most polarizing and consequential national security issues. With public trust in US-extended security deterrence eroding and geopolitical threats mounting, support for nuclear armament is surging. Recent public opinion polls reveal that over 70% of South Koreans now favor acquiring a domestic nuclear arsenal, a sentiment rooted in growing skepticism toward alliance guarantees and a desire for greater self-reliance. Both parties have entertained the notion of nuclear development, though with different motivations. Under Yoon, the PPP endorsed enhanced deterrence capabilities as a supplement to existing alliance structures with the US and Japan. Current PPP candidates continue to echo this line, emphasizing that nuclear options should reinforce – not replace – South Korea’s allied commitments. The DP, by contrast, has historically prioritized engagement with North Korea along with a more autonomous foreign policy. While it publicly frames its interest in nuclear development as a means to strengthen the civil nuclear industry, especially through spent fuel reprocessing, its underlying goal is “strategic independence from the United States.” This approach reimagines South Korea’s security identity, moving away from what it sees as the constraints of allied dependence. 

Civil nuclear energy remains vital to South Korea’s energy strategy. Yet, spent fuel reprocessing blurs the line between civilian use and weapons potential; just 22 pounds of reprocessed plutonium can yield a nuclear bomb. This dual-use ambiguity has raised alarm both domestically and abroad, as policy choices in energy could also shape perceptions of the country’s defense posture. The divergence between the PPP and DP not only reflects differing views on sovereignty and deterrence but also marks two fundamentally different paths for South Korea’s role in the Indo-Pacific. 

Beyond Borders: Diplomatic Ripples of Yoon’s Impeachment 

Yoon’s impeachment introduces significant uncertainty not only to South Korea’s domestic landscape, but also to the region’s diplomatic architecture. As one of the United States’ most trusted allies, South Korea plays a key role in deterring North Korean aggression and counterbalancing China’s growing influence. Now, with Yoon removed and the DP poised to redirect foreign policy, both allies and adversaries are recalibrating their strategic expectations. North Korea has escalated its provocations; China is growing more assertive in contested waters; and Japan, until recently on a path of historic rapprochement, faces renewed doubts about the durability of its cooperation with South Korea. These shifts are not occurring in isolation. These shifts reflect a broader realignment of power dynamics across Northeast Asia, raising urgent questions about deterrence, alliance cohesion, and South Korea’s place in the evolving security order. As the presidential race unfolds, its next leader will inherit both a fractured domestic landscape, and a region teetering on the edge of strategic recalibration. 

Exploiting the Vacuum: North Korea & China’s Strategic Opportunism 

South Korea’s political upheaval has not gone unnoticed by its adversaries. In the wake of Yoon’s declaration of martial law and impeachment, North Korea amplified its rhetoric and provocations, sensing a weakened political center and the potential for a more sympathetic government in Seoul. Kim Jong Un began the new year by labeling South Korea “the most hostile state,” abandoning the long-standing narrative of peaceful unification with a “misguided” and “misled” South. This rhetorical shift serves dual purposes: it justifies an increasingly aggressive posture domestically, while signaling to the international community that negotiations and diplomatic engagement are off the table. North Korea’s alignment with other authoritarian powers further underscores this shift. Its decision to send troops to assist Russia in Ukraine – its first overseas military involvement since the Korean War – provides combat experience, military technology exposure, and an opportunity to test weapons systems. Kim Yo Jong, Kim’s sister and an increasingly powerful voice in the regime, has echoed and even intensified this hardened rhetoric. For South Korea, this presents a sobering strategic dilemma.

Meanwhile, China is seizing on Seoul’s distraction to expand its assertiveness. In January 2025, it installed a “large floating structure” in disputed waters of the Yellow Sea, signaling an intent to normalize territorial claims through incremental occupation. This mirrors preceding Chinese tactics used in the South China Sea, where infrastructure is gradually transformed into de facto territorial claims. However, South Korea’s political paralysis has slowed its response.  Previously aligned with Washington to counterbalance Beijing’s ambitions, Seoul under Yoon pushed back diplomatically and strategically. That coherence is now at risk. For China, a weakened or distracted South Korea offers a strategic opportunity: to erode US influence in the region and to test the cohesion of US-aligned security frameworks. A DP victory could reorient South Korea toward a pro-China posture, with greater diplomatic flexibility and engagement with China. While this may ease tensions in the short term, it could also fracture strategic alignment with the US and Japan at a moment of rising regional pressure. A tilt toward China risks marginalizing South Korea in the very alliance networks that have long underpinned its security while emboldening authoritarian actors. 

Together, North Korea’s belligerence and China’s opportunism signal a growing convergence that threatens to destabilize the current regional balance. Their tactics differ, but both exploit South Korea’s domestic instability to test the strength of US influence and democratic cohesion in the Indo-Pacific. For South Korea, this evolving axis presents a multidimensional threat. Geographically, it faces pressure on both its northern border and western maritime front, stretching its defensive posture thin. Strategically, it risks becoming isolated if its allies perceive hesitation or realignment in Seoul’s foreign policy. More broadly, a weakened deterrence posture could embolden adversaries to further escalate their provocations. Therefore, in a region increasingly shaped by power politics, South Korea’s next administration will have to navigate not just national recovery but the strategic challenge of safeguarding its position. 

Fragile Currents: Japan-ROK After Yoon

While North Korea and China present clear external threats, the potential unraveling of South Korea’s relationship with Japan poses a quieter yet equally consequential risk. During Yoon’s tenure, South Korea and Japan initiated a historic diplomatic thaw –  resolving trade disputes, strengthening intelligence-sharing through GSOMIA, and enhancing trilateral cooperation with the United States. This progress was not unilateral. Then-Prime Minister Fumio Kishida, often regarded as more moderate than his predecessors, took political risks to reciprocate Yoon’s outreach. Yoon’s initiatives paved the way for revitalized trilateral summits and a rare moment of strategic unity, grounded in a shared commitment to future-oriented dialogue. Still, the path to reconciliation proved far from smooth. 

In 2023, Yoon and Kishida announced a landmark plan to resolve one of the most contentious issues in Japan-ROK relations: reparations for Korean victims of Japan’s colonial and wartime forced labor. The proposal called for a South Korean foundation, otherwise known as the “Foundation for Supporting Victims of Imperial Japan’s Forced Mobilization,” to provide compensation to surviving victims and their families. Under this framework, South Korea would bear the financial burden alone; Japanese companies implicated in wartime mobilization were not required to contribute, though they were encouraged to do so voluntarily. The Japanese government declined to issue a new apology, instead stating it would “inherit previous apologies.” While the plan aimed to advance reconciliation, many South Koreans viewed it as unjust and a serious moral failure. The absence of formal accountability or a renewed apology, paired with Japan’s minimal involvement with compensation, led to fierce backlash. A prominent member of Japan’s ruling Liberal Democratic Party (LDP) even gloated that the outcome was a “total victory of Japan,” noting they “didn’t have to concede anything.” Despite domestic outrage, Yoon defended the agreement as a necessary act of diplomatic pragmatism. He argued that Japan was no longer a militaristic aggressor, but a strategic partner. His sincerity in pursuing reconciliation was echoed by current Prime Minister Shigeru Ishiba, whose recent statements reflect an unprecedented willingness to confront Japan’s imperial past. In his recent book, Ishiba wrote, “Without understanding how annexation, which deprived a nation of its culture, language, institutions, and military, damaged the pride and identity of the people of the annexed country, it is impossible to build genuine trust between Japan and South Korea.” Yoon’s overture appears to have reached Japan; whether that momentum continues is uncertain. What now threatens to derail this progress is not Japanese resistance, but the potential foreign policy outlook of a potential DP-led government. 

The DP historically adopted a more confrontational stance toward Japan, framing unresolved historical grievances as a central pillar of its foreign policy. While the importance of addressing historical injustices is undeniable, the DP often prioritizes national indignation over long-term engagement. Its condemnation of Yoon’s labor settlement was aimed at reinforcing public skepticism and nationalist sentiments. During former President Moon Jae-in’s leadership, tensions flared repeatedly as both his administration and then-Prime Minister Shinzo Abe pursued hardline approaches that reignited historical and territorial disputes. Lee Jae-Myung, the DP’s presidential frontrunner, has long expressed strong criticism of Japan. As of 2024, only 28.3% of DP members view Japan favorably –  an indicator of how deeply entrenched anti-Japanese sentiment remains within the party. Though Lee has recently moderated his tone, emphasizing the importance of trilateral relations, his pledge to prioritize South Korea’s national interest first in “every decision” demonstrates a nationalist tilt. The DP’s impeachment motion against Yoon accused him of jeopardizing South Korea’s security by adhering to a “bizarre Japan-centered foreign policy” and appointing “pro-Japanese individuals” to key government roles. Such rhetoric reveals the deeply-rooted opposition to reconciliation with Japan and also signals the likely direction of foreign policy under a potential Lee Jae-Myung administration. 

Ultimately, the future of Japan-South Korea relations hangs in the balance. Yoon’s efforts – however flawed – marked a meaningful attempt to build bridges. Japan, under Ishiba’s leadership, is showing a rare and necessary willingness to confront its imperial past. But that window may not remain open for long. If the DP continues on its current path, dismissing Japan’s gestures or politicizing reconciliation, Tokyo may lose interest in further engagement. It has taken decades for a Japanese leader to articulate a sincere acknowledgment of its colonial transgressions. If Seoul responds with hostility or indifference, the fragile process made thus far could collapse – possibly for another generation. South Korea now stands at a crossroads. One path leads toward continued reconciliation and regional solidarity; the other toward renewed friction with a key democratic ally. The outcome will shape the future of bilateral ties and the strength of the broader coalition confronting authoritarian resurgence in Asia. 

What’s Next? 

At a time when authoritarian powers are growing bolder and regional alliances more vital than ever, the uncertainty surrounding South Korea’s leadership has prompted both allies and adversaries to recalibrate. North Korea is escalating provocations with renewed confidence; China is expanding its influence globally, not just regionally, amid South Korea’s political paralysis; and the fragile diplomatic progress in Japan-ROK relations faces the risk of unraveling. But the true test lies within. South Korea’s next moves will not only define its path forward but could recalibrate the balance of power in the region.  

The issue of nuclear proliferation will remain a central concern. With public support for nuclear armament rising and trust in US security guarantees eroding, the outcome of South Korea’s presidential election will carry significant implications. A shift toward a DP-led government, especially one that continues its current trajectory, could strain security cooperation with the US and Japan. If the US continues its retreat from global geopolitics, this is more than just bilateral alliance management. It is a critical concern to its military presence and security commitments in the Indo-Pacific, with significant consequences for its great power rivalry with China and its ability to deter aggression in the region. China and North Korea, by contrast, stand to gain the most from a Lee Jae-Myung presidency, again, only if the DP maintains its current course. A more autonomous foreign policy, a softened stance on North Korea, and increased distance from Japan could all serve to weaken the trilateral alliance, diminish deterrence capabilities, and create space for authoritarian actors to expand their influence. While Lee has expressed support for trilateral relations, his party’s rhetoric and past actions continue to raise doubts about the depth of that commitment. 

Though the electoral outcome remains uncertain, one reality is becoming clear: the threat of war is no longer a relic of the past. Asia is rapidly becoming a more volatile and fragile region. This is not because of any single leader, but due to a shifting global order where states are behaving in ways not seen for decades. In this multipolar era, South Korea’s next steps will reverberate far beyond the peninsula. They could influence alliance cohesion, shift trade dynamics, and impact the delicate balance between deterrence and escalation. South Korea stands on the edge of a defining moment. The choices it makes in the coming months will shape its role in a changing region and may determine whether it emerges as a unifying force in the Indo-Pacific or a divided actor navigating an increasingly turbulent world. 

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Editors

Julia White, Managing Editor

Ivy Jiang, Copy Editor