People Power Party lawmakers protest in front of National Assembly Speaker Woo Won-shik against the opposition-controlled parliament's move to pass an impeachment motion against Prime Minister and then-acting President Han Duck-soo on Friday. (Im Se-jun/The Korea Herald)
People Power Party lawmakers protest in front of National Assembly Speaker Woo Won-shik against the opposition-controlled parliament's move to pass an impeachment motion against Prime Minister and then-acting President Han Duck-soo on Friday. (Im Se-jun/The Korea Herald)

The Constitutional Court on Sunday faced mounting pressure over deliberations on multiple impeachment cases, including those of President Yoon Suk Yeol and Prime Minister Han Duck-soo, as it needs to make major decisions under an approaching deadline.

With three seats still vacant on the nine-member bench, the court on Friday received a new impeachment case involving Prime Minister Han Duck-soo, who had served as acting president after President Yoon’s impeachment on Dec. 14. The opposition-led National Assembly on Friday passed a motion to impeach Han, which led to the suspension of his powers less than two weeks into his tenure as interim leader.

The court now has a total of 10 impeachment cases to deliberate, with a legal deadline of June 12, 2025 to decide on Yoon's impeachment.

The ruling People Power Party on Friday filed an injunction with the Constitutional Court against Assembly Speaker Woo Won-shik regarding the parliament's decision to pass the impeachment motion against Han. Observers pointed out that the court would have to rule on the injunction before deliberating on Han's impeachment.

Han's impeachment came after the main opposition Democratic Party of Korea, which holds a 170-seat majority in the 300-member parliament, denounced his statement Thursday that he would hold off on appointing the Assembly's three nominees to fill the vacancies on the Constitutional Court. Han's "refusal to nominate Constitutional Court justices" was cited by the Democratic Party as a key reason for his impeachment.

For his decision to defer their appointments, Han cited a lack of bipartisan agreement in view of the ruling party's claim that the prime minister does not have the authority to appoint Constitutional Court justices.

On top of the growing caseload, the terms of acting Chief Justice Moon Hyung-bae and Justice Lee Mi-son, two members of the current six-member bench, are set to end on April 18.

The law states that at least seven justices must participate in a review of an impeachment motion and at least six justices must vote in favor of impeachment for the motion to be upheld.

Despite the existing law, the Constitutional Court recently accepted an injunction request from Lee Jin-sook, chair of the Korea Communications Commission, to temporarily suspend the provision of the Constitutional Court Act requiring seven justices, making it possible to hold hearings with only six.

At the same time, reaching a decision to impeach a president with just six justices could be fraught, as it would require all six justices to accept the parliament's request to remove the president from power.

Three seats on the court’s nine-member bench that are reserved for parliamentary nominees have been vacant since Oct. 17 due to a partisan gridlock.

So far, the Constitutional Court has received a total of 16 impeachment cases since its establishment in 1988. Thirteen of the 16 were submitted to the court after Yoon's inauguration as president in May 2022.