Police officers stand by in front of the Constitutional Court in central Seoul, Thursday. Yonhap

The Constitutional Court formed an eight-member bench as two new justices began their six-year terms on Thursday, paving the way for an accelerated impeachment trial of President Yoon Suk Yeol.

During the inauguration ceremony earlier Thursday, the two new justices — Jeong Gye-seon, nominated by the main opposition Democratic Party of Korea (DPK), and Cho Han-chang, recommended by the ruling People Power Party (PPP) — pledged that they will make every effort to uphold the constitutional order of the country and ensure the protection of people's fundamental rights.

Although the appointment of another justice recommended by the DPK, Ma Eun-hyuk, has been delayed, the court now meets the seven-justice quorum required for deliberations.

The Constitutional Court Act's Article 23 stipulates that a minimum of seven justices are required to deliberate cases and mandates the approval of six justices for impeachment decisions.

Over the past two and a half months, following the retirement of three justices in October, the court temporarily suspended the "seven-member quorum" requirement and operated with a six-member bench.

The establishment of an eight-member bench has addressed concerns and legal questions about the legitimacy of a six-member bench making critical decisions, such as a presidential impeachment. Notably, there is precedent for such cases, as the 2017 impeachment of former President Park Geun-hye was decided by eight justices.

Newly appointed Justices Jeong Gye-seon, right, and Cho Han-chang, left, pose with acting Chief Justice Moon Hyung-bae during the inauguration ceremony at the Constitutional Court in central Seoul, Thursday. Yonhap

With the minimum quorum now met, the impeachment trial of Yoon is expected to gain momentum. The court's spokesperson had previously stated that the court would prioritize deliberating Yoon's case over other impeachment cases.

The court is set to hold the second preparatory hearing for Yoon's impeachment trial on Friday. During the session, representatives from the National Assembly and Yoon's defense team are expected to refine the issues at hand further and coordinate the trial schedule.

The session will also likely confirm Yoon's position on key issues, discuss potential witnesses for future hearings and address requests for the submission of materials from external agencies.

During the first preparatory hearing on Dec. 27, Yoon's legal team expressed its intention to challenge the procedural legitimacy of the impeachment trial, questioning its admissibility based on the legal requirements for impeachment. They also said that the Constitutional Court's delivery process was improper.

Protesters for and against the impeachment of President Yoon Suk Yeol engage in a scuffle in front of the Constitutional Court in Seoul, Thursday. Yonhap

Given that the six-year terms of two justices — Moon Hyung-bae and Lee Mi-son — are set to expire by April 18, it is expected that the Constitutional Court will arrive at the final ruling on Yoon's impeachment case before their terms end.

However, some scholars point out that it is possible the timeline could be extended.

Chang Young-soo, a professor specializing in constitutional law at Korea University School of Law, told The Korea Times that there is a chance that when the two justices retire in mid-April, the court will return to a six-member bench.

"The justices retiring in April were appointed by the president, thus the acting president cannot appoint their replacements. It is both a precedent and the majority opinion among scholars specialized in the field of constitutional law."

"If the court cannot reach a conclusion by April 18, the issue of the six-member bench will recur. With only about three and a half months remaining, it remains uncertain whether all the accumulating legal issues can be resolved at the court," Chang said.

He also said the impeachment case of Yoon is getting more complicated than expected, with an increasing number of legal issues, including treason charges and disputes over the legality of a Seoul district court's warrant issuance according to the country's criminal procedure law. As a result, delays in the trial can be possible.

Since the president intends to fight the case until the end, each related issue is expected to be contested at the court, which will inevitably take more time.

Professor Shin Yul, a political science professor at Myongji University, does not view this matter as overly complex but also warned that if the impeachment case is not resolved by April, it could stretch into the end of Yoon's term.

"If it is not resolved by then, it will not just be a big problem, but it will lead to significant chaos. While impeachment is a domestic political issue, it is externally linked to the possibility of the crisis of the Korean economy," he said, stressing politicians and the judiciary should work toward minimizing this risk.