Will President Yoon's impeachment trial end quickly or drag on?

President Yoon's impeachment trial is now halfway into the proceedings but it could stretch on for longer than scheduled.

It resumes on Tuesday next week, with more key witnesses to speak on the president's martial law decree.

Our Oh Soo-young reports.

The Constitutional Court will resume President Yoon Suk Yeol's impeachment trial, after the Lunar New Year holiday, with more witnesses to testify.

On Tuesday at 2 PM, the Court will hold the trial's fifth hearing, with a focus on questioning key witnesses requested by the National Assembly, which is arguing for Yoon's impeachment.

Beginning at 2:30 PM, three witnesses will each undergo 90 minutes of questioning.

Lee Jin-woo, former Commander of the Capital Defense Command, and Yeo In-hyung, former chief of Military Counterintelligence Command, have both been arrested as key figures implicated in the execution of martial law.

Lee reportedly received calls from President Yoon to drag out legislators from parliament to stop them from voting to lift martial law, while Yeo was in charge of searching and seizing the National Election Commission.

Former intelligence official Hong Jang-won will also testify.

Hong has already said he received orders including from the President to "totally round up and clean up" political opponents.

During the previous hearing, Yoon denied he gave such orders.

Also, former Defense Minister Kim Yong-hyun testified that the President meant for military members to be pulled out of the Assembly, not the members of parliament.

As justices cross-examine the witnesses and their conflicting testimonies, the panel can ask their own questions.

Yoon is likely to attend every trial hearing, and also question witnesses himself as he did in the previous hearing.

"For now, with four hearings left until February 13th, when a verdict will be reached remains unclear.

Observers say by the end of February at the earliest, but there's a fair chance of delays due to legal and political factors at play."

Press officer Cheon Jaehyun said Friday that the Court has selected additional witnesses which include interior minister Lee Sang-min, and National Election Commission Secretary General Kim Yong-bin requested by the National Assembly's side.

On Yoon's side, the Court approved National Security Advisor Shin Won-shik, security expert Baek Jong-wook who was involved in the electoral operations, and Director of the National Intelligence Service Cho Tae-yong.

The selection of witnesses indicates the Court will consider Yoon's argument that suspected election fraud in the General Election last year served as a pretext for declaring martial law.

The Court is still considering further witness requests by the President's team.

If it approves more, the trial could be extended.

Justices could also postpone the hearings considering the pace of Yoon's criminal trial.

Still, the judicial panel has been clear that it's focused on holding speedy trial proceedings.

Meanwhile, another highly anticipated ruling will be delivered on Monday on the eve of Yoon's fifth trial hearing.

The Court will rule on whether Acting President Choi Sang-mok violated the Constitution by appointing only two out of three justices recommended by the National Assembly.

Choi had left out left-leaning candidate Ma Eun-hyuk, raising the need for bipartisan consensus to move forward.

If the court finds the omission unconstitutional, Choi would be under significant pressure to appoint him.

This would mean the Court will operate as a full panel of nine justices also increasing the chance of a two-thirds majority vote required to impeach the President.

Oh Soo-young, Arirang News.