By Eungi Hong
On December 3, 2024, President Yoon Suk-yeol of South Korea unexpectedly declared martial law. After a few hours of chaos, the National Assembly passed a resolution demanding that martial law be lifted, and the president complied. On December 14, the National Assembly voted to impeach the president. While this sequence of events aligns with the framework set forth in the Constitution of South Korea, it has raised contentious questions of constitutionality that will soon be decided.
President Yoon is being held accountable through impeachment proceedings at the Constitutional Court and criminal proceedings at a district court on the charge of insurrection – one of the few charges for which a sitting president does not enjoy immunity from prosecution. This situation has sparked debates about different aspects of the Korean legal framework regarding presidential power. In this essay, I will provide an overview of the key facts and legal questions at the heart of the impeachment and criminal proceedings, as well as relevant precedents and related legal frameworks.
The first legal question is whether a national emergency existed on December 3.
Under the Constitution of the Republic of Korea, the president may declare martial law in response to a national emergency that requires military intervention or the maintenance of public order. Therefore, the first legal question is whether a national emergency existed on December 3. Supreme Court precedents, particularly those related to a 1972 martial law declaration, provide useful guidance on the legal interpretation of “national emergency.” In a criminal case (Case No. 2016DO1397, the Supreme Court of Korea) where an individual faced punishment for allegedly violating the 1972 martial law decree, the court interpreted “military necessity” in the context of a national emergency as referring to situations of extreme disruption to public order, such that the nation’s existence or constitutional order is threatened. The circumstances must make it impossible to manage the emergency using police forces alone, necessitating military intervention to eliminate the direct cause of the disruption. The court decided that the actual domestic and international political and social conditions in 1972 did not meet the threshold for “military necessity”; therefore, the decree itself was deemed unconstitutional and invalid and the defendant was acquitted.
The second issue is the constitutionality of Decree No. 1, issued by the martial law commander immediately after the president’s December 3 martial law order. Decree No.1 banned all political activities of the National Assembly. Neither the Constitution nor the Martial Law Act provides for the suspension of the National Assembly’s activities. Rather, the Constitution stipulates that if the National Assembly votes to lift martial law, the president is obligated to comply. Banning activities by the National Assembly during martial law may impede the exercise of its authority, leaving no mechanism to lift martial law unless the president does so voluntarily.
The deployment of martial law troops to the National Assembly, along with the ban on its activities under Decree No. 1, could indicate an intent to subvert the Constitution.
Third, the deployment of martial law troops to the National Assembly, along with the ban on its activities under Decree No. 1, could indicate an intent to subvert the Constitution. This may constitute grounds for impeachment as a “violation of the Constitution.” It also could qualify as the use of violence with the intent to subvert the Constitution, thus providing a basis for the criminal charge of insurrection.
Impeachment Proceedings at the Constitutional Court
South Korea has an independent Constitutional Court tasked with reviewing the constitutionality of laws and conducting impeachment trials. After the National Assembly passed an impeachment resolution on December 14, President Yoon was immediately suspended from office until the Constitutional Court decides whether to confirm his impeachment or restore him to power.
The impeachment decision requires a “violation of the Constitution or law in the course of official duties.” Two previous presidential impeachment cases provide guiding principles. In the 2004 case of President Roh Moo-hyun, the Constitutional Court ruled that while certain actions by President Roh violated the obligation to maintain political neutrality and therefore were unconstitutional, they did not rise to the level of a serious violation of the Constitution or law that would justify his removal from office. The decision laid out examples of impeachable violations such as abuse of presidential powers to engage in bribery, embezzlement, or corruption and the abuse of authority to infringe on the powers of the National Assembly. However, in the 2017 case of President Park Geun-hye, the Constitutional Court ruled that her involvement in corruption and abuse of power constituted serious violations of the Constitution and the law and warranted her removal from office.
Only grave violations undermining the principles of constitutional democracy and public trust can justify the removal of a sitting president.
From these cases we can conclude that only grave violations undermining the principles of constitutional democracy and public trust can justify the removal of a sitting president.
Criminal Trial for Insurrection
Under the Constitution, the president is immune from criminal prosecution while in office except for charges of insurrection or treason. President Yoon was indicted on January 26 on the charge of insurrection for the December 3 martial law declaration.
Although no previous sitting president has faced insurrection charges, former Presidents Chun Doo-hwan and Roh Tae-woo were prosecuted for insurrection after their terms ended for orchestrating a military coup in May 1980. The Supreme Court’s landmark 1997 ruling in their case established that even a regime established through insurrection is subject to criminal punishment.
Insurrection requires “the use of violence with the intent to subvert the Constitution.” The key legal question is whether President Yoon’s declaration of martial law – particularly Decree No. 1, which restricted the activities of the National Assembly – and subsequent actions, such as deploying troops to the National Assembly, meet this threshold. The 1997 precedent might provide guiding principles for interpreting whether such actions constitute insurrection under the law.
Both court proceedings are under time pressure. In the impeachment proceedings, two justices of the Constitutional Court are due to retire in April 2025. The Constitution requires an affirmative vote of at least six justices to impeach a president, and the nine-justice bench is already missing one person. If two retire, the six remaining justices would have to agree unanimously to impeach the president.
Timing is also a crucial factor in the broader political landscape. If the Constitutional Court removes President Yoon from office, the next presidential election must be held within 60 days. The current frontrunner is Lee Jae-Myung, a former presidential candidate from the opposition Democratic Party who lost to Yoon in the 2022 election. But Lee is fighting multiple charges of corruption unrelated to the constitutional drama. If the Supreme Court delivers a final verdict in one of Lee’s trials before the next presidential election, Lee could lose his eligibility to run for office. Thus the timing of the Constitutional Court’s decision on President Yoon and the Supreme Court’s ruling on Lee are deeply intertwined from a political perspective. This serves to intensify public polarization, which already has led to violent disruptions.
President Yoon’s declaration of martial law presented severe challenges to the nation’s legal and political systems. The responses of other institutions, especially the courts, may serve as a testament to the resilience of South Korea’s Constitution and democracy.
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Eungi Hong is a is a presiding judge in the Gwangju District Court and a visiting scholar at the U.S.-Asia Law Institute.
Suggested citation:
Eungi Hong, “South Korea’s President on Trial: An Explainer,” USALI Perspectives, 5, No. 6, February 24, 2025, https://usali.org/usali-perspectives-blog/south-koreas-president-on-trial-an-explainer.
The views expressed in USALI Perspectives essays are those of the authors, and do not represent those of USALI or NYU.
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