President Yoon Suk Yeol urged the Constitutional Court to guarantee argument and substantiation of alleged election rigging during his impeachment trial.

Cho Dae-hyun, one of the lawyers on Yoon's defense team, said on Thursday that the alleged rigging is a key factor that prompted the president to declare martial law.

Cho said resolving the allegations and securing a transparent and fair election system would establish constitutional order under popular sovereignty.

The lawyer claimed that the main opposition Democratic Party(DP), with a majority during the 21st National Assembly, eased rules to allow more Chinese nationals to enter the country, which as a consequence helped spur their espionage activity.

Denying as false provocation an allegation that Yoon attempted to ban parliamentary operation and set up an emergency legislative body under martial law, Cho said Yoon did not order the arrest of politicians and that troops did not make such an attempt.

The lawyer said Yoon was also aware that he would soon have to lift martial law after the opposition-strong parliament passes a motion to request its revocation.