—Yoomin Won, Associate Professor, Seoul National University
[Editor’s Note: This is one of our ICONnect columns. For more information on our 2025 columnists, see here.]
On June 3, 2025, South Korea elected a new president of the republic. Lee Jae-myung is now elected from the presidential election that took place following the impeachment decision of the Constitutional Court of Korea on April 4, 2025.[1] Lee Jae-myung’s five-year term began as soon as the Election Commission of Korea announced the winning candidate as elected the next morning—unlike pre-scheduled elections, usually held at the end of a president’s term, which allow a preparation period for the new government.
On the day of the presidential election, the acting president of South Korea was Lee Ju-ho, Minister of Education. He was No. 4 in the government hierarchy, third in line if the presidency becomes vacant or the president is unable to perform their duties.[2] When the President Yoon Suk-yeol, No. 1 in the government, was suspended due to the National Assembly’s resolution to submit an impeachment case to the Constitutional Court on December 14, 2024, it was Prime Minister Han Duk-soo, No. 2 in the government, who took over as acting president. Thirteen days later, Han was also suspended after an impeachment motion against him passed. Then the Minister of Economy and Finance, Choi Sang-mok, No. 3, assumed the position of acting president. Han was reinstated as acting president following the Constitutional Court’s ruling striking down his impeachment on March 24, 2025.[3] The Court’s impeachment decision against Yoon on April 4, 2025, advanced the presidential election to be held on June 3. In the afternoon of May 1, Han announced his resignation to run for the presidency. With Choi’s sudden resignation that night, Lee Ju-ho, No. 4 in line, became the acting president. It was a real-life version of the American TV series Designated Survivor.
At the heart of this political chaos lies the legal issue of whether the acting president can—or should—appoint justices of the Constitutional Court. The Court holds the power to decide the fate of the president, including possibly influencing the timing of the presidential election by choosing when to announce its decision.[4] When this political drama began with the declaration of martial law on December 3, 2024, only six out of nine justices were sitting on the Constitutional Court. Nominating justices to the Court was like playing a joker card to change the game.
The first episode begins when Han refused to appoint justices in December 2024. The Constitutional Court of Korea is composed of nine justices, appointed by the President: three from nominees selected by the National Assembly, and three from those nominated by the Chief Justice of the Supreme Court. Three seats had been vacant since October 2024—those to be selected by the National Assembly.[5] Filling these seats was crucial due to restrictions on voting at the Court. The Court may proceed with hearings if at least seven justices are present.[6] To impeach a president, at least six justices must agree.[7] Due to an earlier decision to suspend the seven-justice requirement,[8] the case could proceed—but all six votes were still required to impeach the president. As soon as the impeachment motion against Yoon passed, the National Assembly—the opposition being in the majority—initiated and completed the nomination process for three justices and requested acting president Han to appoint them. Han declared he would not do so “until both the ruling party and the opposition party agree.” The next day, December 27, 2024, an impeachment motion against Han was passed.[9]
The second episode began with the next acting president. The Minister of Economy and Finance Choi, who succeeded Han, was to appoint the three justices selected by the National Assembly. This time, he appointed two justices but withheld the appointment of the third, Ma Eun-hyeok, citing a lack of bipartisan agreement. His actions failed to fill the full bench but brought the number of justices to eight. The National Assembly filed a competence dispute to the Constitutional Court. On February 27, 2025, the Court unanimously ruled that Choi’s refusal violated the National Assembly’s authority to select justices.[10] Despite the ruling, Choi continued to refuse the appointment and never fulfilled it before his role ended with Han’s reinstatement on March 24. The appointment authority returned to Han. Meanwhile, the National Assembly initiated impeachment proceedings against Choi for his refusal. The motion failed due to Choi’s sudden resignation on May 1, just moments before the plenary vote.
The third episode of this season—hopefully the last—stars Prime Minister Han once again. Until now, the issue was whether the acting president should appoint justices selected by the National Assembly. This time, the question was whether the acting president may appoint justices from the president’s own quota. The Constitutional Court, which had announced President Yoon’s impeachment on April 4, 2025, was faced with the end of the terms of two justices—including the acting chief justice—on April 18. These vacancies were due to be filled by presidential nomination. On April 8, Han, reinstated as acting president, appointed Justice Ma Eun-hyeok (the seat disputed for months), along with two justices to fill the upcoming vacancies. This immediately raised concerns about whether an acting president, who lacks democratic legitimacy, may exercise the president’s power to appoint justices—or whether he should refrain and leave these decisions to the soon-to-be-elected president. Moreover, one of Han’s appointees, Lee Wan-kyu, Minister of Government Legislation and a lifelong friend of Yoon, was under police investigation for allegedly abetting insurrection and destroying evidence related to the martial law declaration. A constitutional complaint and an injunction request were immediately filed. On April 16, the Court—now with all nine justices including newly appointed Justice Ma—unanimously granted an injunction suspending Han’s appointment of the two justices, just two days before the incumbent justices were due to step down after their six-year term.[11]
The political drama that began with the unexpected declaration of martial law in December 2024 has now ended with the election of a new president. At the center of the turmoil lies the legal issue of whether acting presidents can appoint justices to the Constitutional Court. It was all a chain reaction involving political and judicial actors. Numbers 1, 2, and 3 of the government were subject to rulings by the Court—but still held the power to shape the Court by appointing its members. The National Assembly, dominated by the opposition, freely exercised its power of impeachment. This resulted in unprecedented discord between the executive, legislative, and judicial branches. Each episode ended not with political compromise but with judicial rulings, as political actors repeatedly turned to the courts for resolution. Now that the emergency sparked by martial law and impeachment is over, it is time to move toward a peaceful conclusion to this extraordinary season.
Suggested citation: Yoomin Won, Constitutional Court Appointments and Acting Presidents in South Korea: The Messy Aftermath of the Yoon Impeachment, Int’l J. Const. L. Blog, June 4, 2025, at: http://www.iconnectblog.com/constitutional-court-appointments-and-acting-presidents-in-south-korea-the-messy-aftermath-of-the-yoon-impeachment/
[1] Constitutional Court of Korea, 2024Hun-Na8, Apr. 4, 2025.
[2] Article 71 of the Korean Constitution.
[3] Constitutional Court of Korea, 2024Hun-Na9, Mar. 24, 2025.
[4] Article 68(2) of the Korean Constitution provides that the successor shall be elected within 60 days in case of a vacancy, disqualification by a court ruling or for any other reason.
[5] Article 111(2),(3) of the Korean Constitution.
[6] Article 23(1) of the Constitutional Court Act.
[7] Article 113(1) of the Korean Constitution.
[8] Constitutional Court of Korea, 2024Hun-Sa1250, Oct. 14, 2024.
[9] The Constitutional Court later ruled that his refusal to appoint justices of the Court is unconstitutional but not grave enough to impeach him. Constitutional Court of Korea, 2024Hun-Na9, Mar 24, 2025.
[10] Constitutional Court of Korea, 2025Hun-Ra1, Feb.27, 2025.
[11] Constitutional Court of Korea, 2025Hun-Sa399, Apr. 16, 2025.
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