Acting President and Prime Minister Han Duck-soo delivers a public address at the Government Complex Seoul in Jongno District, Seoul, on Dec. 26. /Yonhap News

The Democratic Party (DP) of South Korea announced on Dec. 26 its plan to propose an impeachment motion against Acting President Han Duck-soo, aiming for its passage in a plenary session of the National Assembly on Dec. 27.

The move came after Han deferred the appointment of three Constitutional Court justices recommended by the National Assembly, a decision that prompted the party to act on its prior warnings to pursue impeachment. If carried out, it would mark the first time in S. Korean constitutional history that impeachment proceedings have been initiated against an acting president.

Park Chan-dae, the DP’s floor leader, told reporters ahead of a general assembly meeting, “Prime Minister Han Duck-soo officially declared today through a statement that he will not fulfill his constitutional responsibility to appoint Constitutional Court justices. This statement essentially acknowledges that he is not an acting president but a ‘proxy for insurrection.’”

Park criticized Han’s justification, saying, “The prime minister exercises veto power, which is the most active form of authority, but refuses to perform the formal duty of appointing Constitutional Court justices. This absurd logic confirms that Han neither qualifies to serve as acting president nor has the will to uphold the Constitution.” He added that the DP would immediately submit the impeachment motion and present it during the day’s plenary session. The party plans to pass the motion in the National Assembly on Dec. 27.

The DP outlined five reasons for the impeachment, including Han’s recommendation that President Yoon Suk-yeol veto the Marine Corps special prosecutor bill, which sought an independent investigation into the suspicious death of a Marine during a flood rescue operation, and the Kim Keon-hee special prosecutor bill, which called for a probe into alleged corruption and stock manipulation involving First Lady Kim Keon-hee. The party claims both bills involved conflicts of interest for the president, making Han’s role in advising their veto problematic.

Other reasons cited include Han’s alleged involvement in convening a cabinet meeting to address procedural gaps for declaring martial law, his purported role in cooperating with former People Power Party leader Han Dong-hoon to transfer power after the insurrection, his failure to comply with obligations to recommend a permanent special prosecutor for investigating treason charges, and his refusal to appoint Constitutional Court justices, allegedly delaying efforts to stabilize the political crisis.

Noh Jong-myeon, a spokesperson of DP, emphasized, “The fundamental reason for impeachment is that Han was briefed in advance on the insurrection plans.” The party claims former Defense Minister Kim Yong-hyun reported the martial law proposal to Acting President Han before submitting it to President Yoon, making Han a key figure in the crisis. However, Han’s office has denied the allegations, asserting that he had no prior knowledge of any such plans until President Yoon discussed the martial law declaration.

Disputes remain over the required number of votes to pass the impeachment motion. The ruling party argues it should require approval from two-thirds of the total National Assembly members (200 votes), as applied to a president, while the opposition maintains that a simple majority of 151 votes, the threshold for impeaching a prime minister, is sufficient. Woo Won-shik, the National Assembly Speaker, who holds the authority to decide the quorum, has yet to clarify his position.