The 2024 Self-Coup in South Korea: Democracy Challenged and Saved

South Korea’s 2024 Martial Law Crisis marked the country’s gravest democratic crisis since democratisation. President Yoon’s declaration of martial law and mobilisation of military troops amounted to a self-coup, which exposed the ways partisan security networks and polarised elites can undermine even well-institutionalised democracies.

• Years of democratic backsliding culminated in this crisis, for which long-standing polarisation and Yoon’s politicisation of the security sector set the stage. Short-term triggers included probes targeting the first lady, election fraud conspiracy theories, and pressure after the opposition’s 2024 landslide victory.

• On 3 December 2024 elite military units were mobilised to occupy key institutions. Martial law was lifted after six hours, but the crisis continued: while Yoon was detained and awaiting the result of the impeachment procedure, pro-Yoon and anti-Yoon forces clashed in the streets.

• International responses were muted: the US expressed confidence in Korea’s democratic institutions but avoided direct criticism, Japan issued cautious statements, the EU voiced concern over democratic backsliding, and China restrained itself despite rising anti-Beijing rhetoric.

• While the Constitutional Court confirmed Yoon’s impeachment on 4 April 2025, the crisis revealed both the resilience and vulnerability of South Korean democracy: institutional pushback blocked the self-coup, but polarisation and partisan networks in the security sector could lead to further erosion of democracy.

Policy Implications

Europe should support South Korea’s democratic resilience by promoting civil–military accountability, countering polarisation, and strengthening civil society and oversight institutions. This will help stabilise a key partner in Asia, reinforce Europe’s normative agenda, and provide lessons for safeguarding democracy at home.

The Self-Coup Attempt and the Crisis of Korean Democracy

In recent months, South Korea has been experiencing a political drama unprecedented since the end of the military dictatorship in 1987. The crisis climaxed with President Yoon Suk Yeol’s declaration of martial law on 3 December 2024. With martial law invoked, military special forces were mobilised to shut down the National Assembly and raid the National Election Commission (NEC). However, a delay in military mobilisation gave lawmakers, mostly from the opposition but also including members of Yoon’s People Power Party (PPP), the opportunity to enter the parliamentary building. A total of 190 lawmakers unanimously voted to repeal the declaration. Six hours after his initial declaration, Yoon rescinded his order.

But this was not the end of the crisis. On 14 December the National Assembly voted to impeach the president. A weeks-long stalemate followed, during which Yoon holed up in his presidential residence, protected by hundreds of Presidential Security Service agents. It was only on 15 January 2025 that public prosecutors and police were able to execute a detention warrant against the impeached president. On 4 April the Korean Constitutional Court voted unanimously to uphold Yoon’s impeachment, ruling that Yoon’s martial law decree had violated constitutional procedure and disregarded conditions stipulated in the Martial Law Act that ensure the National Assembly’s authority to request the lifting of martial law. The PPP said that it “humbly” accepted the ruling (Sang-Hun et al. 2025).

Political scientists classify Yoon’s actions as an attempted “self-coup,” an illegal effort by an incumbent executive to consolidate or expand power through interference with the legislature or judiciary, typically involving the use or threat of force. Scholarship agrees that a self-coup attempt will succeed only if it has at least tacit support from the security sector. The Korean Martial Law Crisis is no exception: Yoon’s attempt was supported by ruling-party hardliners and loyalists in crucial command positions in the military and security apparatus; it failed only because opposition parties and civil society mobilised a swift and unified resistance. However, a less amateurish attempt might have allowed Yoon to establish an elected dictatorship, not least due to the partisan loyalty of core military leaders to the president.

Democratic Decay and the Road to the Self-Coup Attempt

The 3 December self-coup was preceded by polarisation and political stalemate between the conservative president and the liberal opposition. Yoon, a former prosecutor general, entered politics without prior elected-office experience. In the fiercely contested 2022 presidential race, he narrowly won by less than one percentage point. As his conservative PPP lacked a parliamentary majority, and the liberal opposition, led by the Democratic Party (DP), did not have the numbers to override a presidential veto, the two sides almost immediately began to play constitutional hardball.

While many details about the events of 3 December remain unclear, recent revelations indicate that plans to declare martial law were formulated as early as March 2024. Yoon’s martial law declaration, thus, did not mark the start of South Korea’s democratic crisis. Rather, it was the culmination of long-term processes of democratic erosion and defects in the democratic governance of Korea’s security sector, exacerbated by a series of more immediate political triggers.

Long-Term Democratic Erosion, and Challenges in Civil–Military Relations

At a first glance, the decay of Korean democracy under Yoon repeated a pattern of democratic erosion that had already occurred under previous conservative administrations – those of President Lee Myung-bak (2008–2013) and President Park Geun-hye (2013–2016). In 2016 dissatisfaction with Park’s governance and high-level corruption scandals triggered mass protests and ultimately led to her impeachment in December of that year. However, beyond the fact that neither Lee nor Park attempted a self-coup, two crucial differences set Yoon’s presidency apart: First, Yoon heavily instrumentalised prosecutorial power by appointing former prosecutors to key Cabinet and presidential-office positions, systematically using prosecutors to target political opponents and intimidate critical media and civil society. Although prosecutorial misuse is not unprecedented – President Moon Jae-in (2017–2022) also faced criticism in this regard, and Korea has a history of politically motivated judicial actions – the Yoon administration magnified the pressure on press freedom, freedom of peaceful assembly, and civic spaces. Yoon frequently circumvented legal procedures and sidelined the opposition-controlled National Assembly, openly disregarding constitutional norms, particularly concerning matters related to his family.

Second, President Yoon attempted to build a network of loyalists in the security sector by appointing alumni from his former high school to key positions in the military, prosecutor’s office, police, and national intelligence. This significantly intensified existing governance challenges in civil–military relations and weakened democratic oversight of the security apparatus. Although South Korea achieved critical successes in reforming its national security apparatus and civil–military relations after 1987, many observers and experts had noted remaining shortcomings, especially weak legislative oversight and ongoing dominance of the military in the defence bureaucracy, the politicised role of law enforcement and public prosecutors, and pathologies in the intelligence services. Even in the final phase of Park’s term, there had been reports – later substantiated by published evidence – of her loyalists within the security apparatus attempting to influence parliamentary elections, manipulate public opinion, and create blacklists of political opponents (Doucette and Koo 2016: 199). Following Park’s impeachment, further revelations emerged that while the Constitutional Court deliberated on her removal, the defence minister had ordered the commander of the Defence Security Command to prepare a martial law plan aimed at suppressing protests in case Park was reinstated (Lee 2023). These disclosures triggered significant political backlash, prompting the liberal Moon to initiate institutional reforms of the national security sector – reforms that Yoon later reversed.

Immediate Political Trigger Events

There are several factors which may have triggered President Yoon’s dramatic escalation of the political crisis: First, following the April 2024 legislative elections, conservative lawmakers promoted a conspiracy theory concerning election fraud in the 2020 and 2024 elections. Yoon used these unsubstantiated claims as ex-post justification for the martial law decree.

Second, legal troubles involving First Lady Kim Keon-hee likely increased pressure on Yoon. Kim faced allegations concerning involvement in stock manipulation cases in the early 2010s and in 2023/2024 (Goh and Jeon 2025). According to recent testimony by former defence minister Kim Yong-hyun, Yoon explicitly linked the timing of martial law to opposition moves against his spouse.

Third, the opposition’s landslide victory in the 2024 elections exacerbated the political confrontation. From July 2024 onward, opposition lawmakers challenged Yoon’s appointments for defence minister and key military command positions, speculating whether these appointments were precursors to an imminent declaration of martial law. Opposition lawmakers also undertook impeachment proceedings against high-ranking executive officials and used the potential reduction of the 2025 budget proposal as a bargaining tactic, which Yoon later cited as justification for martial law (Chea 2024).

Fourth, the Myeong Tae-kyun corruption scandal of September 2024 intensified political polarisation. The scandal, involving interference in the conservative party’s nomination process for the 2024 elections, highlighted government cronyism and systemic corruption (Choi 2024).

Finally, conservative conspiracy theorists promoted narratives about “pro-Chinese” or “pro-North Korean” factions infiltrating South Korea’s state and politics – claims echoed by Yoon himself, who explicitly referred to pro-Pyongyang forces and the necessity to restore constitutional order in his martial law announcements.

The Martial Law Crisis and Its Aftermath

Mobilising the National Security Apparatus

During Yoon’s self-coup attempt, Korea’s national security apparatus was extensively mobilised. The main targets of the martial law operation included the NEC offices, the Election Training Institute in Suwon, the National Assembly, and the office building of Ddanzi Ilbo, a prominent pro-DP online media outlet. The government deployed specialised national security units alongside select military combat forces and police. These included the Capital Defence Command (CDC), Defence Counterintelligence Command (DCC), Korea Defence Intelligence Command (KDIC), and elements of the Republic of Korea Army Special Warfare Command (ROK-SWC), notably the elite 707th Special Missions Group.

Throughout 2024 several secret meetings took place involving commanders of these units alongside Minister of National Defence Kim and occasionally President Yoon. Allegedly, General (ret.) Roh Sang-won, former KDIC commander, who had been discharged from the military due to sexual harassment charges, also played a critical role in the 3 December martial law operation. He reportedly held discussions regarding the martial law plan with active-duty military officers, including KDIC Commander Moon Sang-ho, leveraging personal connections and influence over career promotions to recruit incumbent officers for the operation.

On 3 December 2024 military special forces were primarily responsible for securing the perimeters and taking control of targeted buildings or individuals, while military intelligence units were tasked with arresting specific individuals – including NEC officials and prominent opposition legislators – and confiscating election-related data from the NEC. Although martial law forces successfully secured the NEC buildings, their attempts to seize the National Assembly encountered resistance. DP leader Lee Jae-myung livestreamed himself rushing to the parliament building, calling upon supporters and ordinary citizens to defend the legislature. Many civilians responded, gathering at the parliamentary compound and physically confronting military personnel, ultimately preventing them from entering the main hall of the National Assembly. This allowed 190 lawmakers to convene and unanimously request that President Yoon revoke martial law only hours after its declaration.

The Aftermath of Martial Law: Political Turmoil Continues

In the weeks following the revocation of martial law, political turmoil only deepened, as the National Assembly passed an impeachment motion on 14 December 2024. The first major challenge was the vacancy of three seats on the Constitutional Court, which is responsible for adjudicating Yoon’s impeachment. On 26 December the National Assembly approved the appointment of one justice nominated by the ruling PPP and two justices nominated by the opposition. However, Prime Minister Han Deok-soo, acting president at the time, refused to appoint three nominees, citing lack of bipartisan cooperation. This triggered a new constitutional crisis, culminating in Han’s own impeachment by the opposition-controlled National Assembly. Minister of Economy and Finance Choi Sang-mok then assumed the role of acting president and proceeded to appoint two of the three justices, while the second opposition nominee remained stalled.

On 31 December 2024 the Seoul Western District Court issued an arrest warrant for President Yoon Suk-yeol after he failed to comply with three summonses from the Corruption Investigation Office for High-Ranking Officials (CIO), which was investigating his role in the Martial Law Crisis. After an initial attempt to arrest Yoon failed due to the obstruction by the Presidential Security Service, the CIO with support from police investigators successfully took him into custody on 15 January 2025, holding him at the Seoul Detention Centre – making him the first sitting president in South Korean history to be arrested.

On 19 January the Seoul Western District Court issued a detention warrant for President Yoon. In response, a violent mob of his supporters – who had been protesting outside the courthouse – overpowered police, stormed the building, vandalised property, and searched for the judge who had issued the warrant. In late February, the Constitutional Court’s eight judges began to deliberate Yoon’s impeachment in closed session. On 8 March Yoon was released from detention and returned to his official residence to await the court’s final decision. On 24 March a Constitutional Court ruling reinstated Han Deok-soo as acting president. Finally, on 4 April the Court endorsed the National Assembly’s decision to impeach Yoon.

Domestic and International Reactions

Although initial public opinion was overwhelmingly opposed to martial law, a growing number of conservative and right-wing organisations have since rallied behind President Yoon and justified the imposition of martial law. Liberal and progressive forces, however, have remained opposed to the president and his actions, arguing that impeachment was the only appropriate response to the clearly unconstitutional nature of Yoon’s actions.

Compounding the situation are other political crises, including the impeachment of Han, disputes over the appointment of the three Constitutional Court justices, and the decision to release Yoon from detention. These overlapping conflicts have brought formal political dialogue between the opposing political camps to a halt. On the streets, political polarisation has reached new heights, with government supporters branding opposition figures as pro-China and pro-North Korea, while opposition groups accuse Yoon supporters of advocating insurrection.

Internationally, the United States has a particularly strong interest in South Korea’s political stability, given the presence of US forces on the peninsula and Seoul’s tradition of consulting Washington on major policy shifts. However, the US National Security Council was reportedly not informed in advance of Yoon’s martial law declaration. Both the Biden and the Trump administrations refrained from direct involvement, instead expressing confidence in South Korea’s democratic institutions and processes.

In response to the crisis, Prime Minister Shigeru Ishiba of Japan postponed a planned visit to Seoul originally scheduled for early January. The European Union has stated that it is closely monitoring developments. China, meanwhile, finds itself in a particularly delicate position, as pro-Yoon demonstrators have framed their movement in strongly anti-China terms, calling for the eradication of so-called “pro-China cartels.” There have even been reports of Chinese nationals being verbally abused and physically intimidated near protest sites.

Implications for Democracy and Security Sector Governance

What, then, are the implications of the martial law fiasco and the subsequent political drama for democracy and security sector governance in South Korea? While legitimate debates exist about the roles of both the liberal opposition and the conservative PPP in the erosion of democratic principles and practices leading up to 3 December 2024, one fact stands out: an elected president tried to suspend parliament and curtail political rights and civil liberties – and a substantial segment of the political elite and the citizenry found such a flagrant violation of democratic rules acceptable. This indicates that democratic norms and practices in what was once considered one of Asia’s most vibrant democracies are no longer “the only game in town.”

Many scholars have noted that both the onset and outcome of Yoon’s self-coup attempt demonstrate strengths and weaknesses of democratic resilience in South Korea (Croissant 2024; Lee and Lee 2025). Democratic resilience depends on strong political institutions, elite commitment to democratic pluralism, tamed political polarisation, a robust civil society, and citizens’ trust in democratic principles (Croissant and Lott 2024). The broad civic resistance to Yoon’s power grab and the functioning mechanisms of horizontal accountability underscore the strength of South Korea’s democracy. However, the system failed to both mitigate political tensions and prevent the president’s abuse of executive power. Long-standing structural challenges – including deep polarisation, the personalisation of partisanship, flaws in the electoral system, and a confrontational presidential model – have only intensified. In this context, there are growing signs of what Juan Linz (1978) called a “semi-loyal” opposition to democracy: actors who accept democratic rules in principle but undermine them in practice when power is at stake. The ruling party’s reluctance to hold one of its own accountable for a grave violation of democratic norms reflects this semi-loyal stance. Therefore, one of the most worrisome implications of the martial law drama may be that it has further weakened democracy’s capacity to recover and increased its vulnerability to a future acceleration of democratic backsliding. In this regard, Yoon’s PPP saying that it “humbly” accepted the Constitutional Court’s ruling might be a silver lining (Sang-Hun et al. 2025). The upcoming early presidential elections, scheduled for 3 June 2025, will reveal whether political de-escalation or further toxic polarisation will take the upper hand.

However, the events of 3 December also put a spotlight on the ways in which South Korea’s civil–military relations likely contributed to the Martial Law Crisis of 2024. First, South Korea’s Constitution concentrates power in the presidency with relatively limited legislative oversight. Despite the existence of a National Defence Committee, the National Assembly lacks the authority to directly veto legislation or independently review major defence policies and procurement decisions. Moreover, a substantial number of committee members are former military officers who maintain close ties to the armed forces. Such weakly institutionalised legislative oversight allows for a determined president to mobilise the military for their personal political ends (Transparency International 2021).

Second, while civilians make up the majority of the Ministry of National Defence’s staff, authority over core defence matters such as strategy, doctrine, education, and promotions resides outside the ministry’s civilian bureaucracy, being controlled by the Joint Chiefs of Staff (JCS) and service headquarters (Kim and Kuehn 2022). This further dilutes legislative oversight, which made it easier for President Yoon to co-opt military leaders for his ends in 2024.

Third, the crisis highlighted a worrisome failure within the South Korean armed forces to internalise professional ethics of a democratic military, particularly the duty to refuse unlawful orders. As highlighted by the ruling of the Constitutional Court, Yoon’s martial law declaration violated constitutional requirements and stipulations in the Martial Law Act. While notable cases of passive resistance occurred, with some military personnel refusing to execute orders or intentionally stalling operations, significant elements of the deployed military units complied with these unlawful orders, casting doubt on their commitment to constitutional norms. Analysts have long identified ideological biases rooted in the long shadow of South Korea’s autocratic past, in addition to rampant factionalism within the military leadership. Under Yoon, recruiting like-minded, personally loyal officers for leading command positions facilitated collusion and the temporary breakdown of the military professional norm of refusing unlawful orders (Kim 2025).

Outlook

Existing research highlights a number of key factors that have ensured the resilience of South Korea’s democracy during the current global wave of autocratisation and repeated attacks from within: the interplay of a vibrant and mobilised civil society, robust democratic institutions, and a deeply rooted political culture that affirms the legitimacy of democratic governance (Cho 2024). These same factors were crucial in safeguarding South Korea’s democracy during the Martial Law Crisis of December 2024, when democratic norms were put to a severe test. Key democratic institutions – the National Assembly and the Constitutional Court – fulfilled their constitutional roles under intense pressure. Notably, even some members of President Yoon’s own party broke ranks to vote in favour of rescinding the martial law order. Most importantly, South Korea’s vibrant civil society once again emerged as a bulwark against authoritarian overreach.

Yet, the crisis also exposed two enduring fault lines in South Korea’s democracy: The first is the high degree of political polarisation, which has deepened in recent years and now permeates both elite competition and public discourse. While civic activism has been a cornerstone of democratic resilience, it has also contributed to the rise of highly contentious, adversarial politics. Opposing camps increasingly view one another not as legitimate rivals but as existential threats, fuelling the demonisation of opponents and the normalisation of conspiracy narratives. This zero-sum mentality undermines democratic norms of mutual tolerance and institutional forbearance, making it more difficult to achieve cross-party consensus and safeguard the democratic rules of the game. The Martial Law Crisis revealed how quickly polarised narratives – such as election fraud or alleged infiltration by “pro-North” forces – can mobilise political support for antidemocratic actions.

Second, the events of December 2024 further highlighted long-standing problems in Korean civil–military relations that have remained unresolved. A crucial finding of recent research on democratic backsliding is that militaries are potential “gatekeepers” of executive self-coups, and the decisions of key military commanders often determine whether democracy survives or collapses. The Martial Law Crisis exposed vulnerabilities in the South Korean military’s commitment to democratic norms – vulnerabilities rooted in historical legacies, ideological alignment with conservative political factions, and entrenched factionalism in senior leadership appointments.

To strengthen the core pillars of democratic resilience, South Korean political actors and civil society are well advised to actively reinforce the foundations that safeguarded democracy during the 2024 crisis. Political elites across the spectrum need to commit to democratic norms of mutual tolerance and institutional restraint, resisting the temptation to exploit polarisation for short-term gain. Civil society must maintain its watchdog function while also fostering spaces for inclusive, cross-partisan dialogue to rebuild trust and reduce social fragmentation. Educational institutions, civic organisations, and the media all have a role to play in promoting democratic literacy and countering disinformation and misinformation. Strengthening the legitimacy of democratic institutions in the eyes of the public – and encouraging a culture of pluralism over zero-sum antagonism – will be critical to ensuring South Korea’s democracy remains resilient in the face of future challenges.

A key area requiring particular attention is the reform of civil–military relations and the democratic governance of the security sector. Potential avenues for progress include enhancing legislative oversight of defence and security affairs, establishing an independent civilian watchdog to handle internal complaints, and reforming military education to promote constitutional loyalty and political neutrality. Additionally, promotion and appointment processes must be depoliticised to ensure that merit, not factional loyalty, determines leadership within the armed forces.

For German and European actors, South Korea’s Martial Law Crisis underscores the need for proactive support to partner democracies facing internal threats to democratic governance. Drawing on its post-Cold War experience, Europe is well positioned to share best practices and foster dialogue to strengthen legislative oversight, support military education reform, and promote constitutional norms within the security sector. Equally important is addressing the deeper societal fault line of polarisation. European support could help bolster civic education, pluralist political culture, and independent institutions through funding, exchanges, and capacity-building with civil society, media, and legislatures. By reinforcing the core pillars of South Korea’s democratic resilience, Europe not only supports a key partner in a vital region but also strengthens its own credibility and learns valuable lessons for defending democracy at home.

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