Former South Korean President Yoon Suk-yeol attends his first criminal trial on insurrection charges at the Seoul Central District Court in in a black security vehicle on April 14, 2025.Photo: VCG

Former South Korean President Yoon Suk-yeol on Monday attended his first criminal trial on insurrection charges related to his attempt to impose martial law in December, the Yonhap News Agency reported. 

Yoon defended his actions during the trial, saying his attempt to impose martial law in December did not amount to an insurrection, Yonhap said. 

"The indictment simply lists the details of the investigation into what happened during the several hours between 10:30 pm December 3 [2024] and 2 to 3 am," Yoon said after the prosecution presented a summary of its charges, according to the South Korean media report. 

"It goes against legal principles to build an insurrection case based on an indictment that looks like a printout of an incident that lasted only a few hours and was lifted immediately in a nonviolent manner upon accepting the National Assembly's demand to lift it," the former South Korean President was quoted as saying in the Yonhap report.

Yoon faces charges of leading an insurrection through his brief imposition of martial law on December 3, 2024, which involved the deployment of troops to the National Assembly in an alleged attempt to prevent lawmakers from voting down the decree, Yonhap said.   

Yoon was impeached by the National Assembly days later and removed from office on April 4 after the Constitutional Court unanimously upheld his impeachment, according to Yonhap. 

According to the Criminal Act of South Korea, those convicted of leading an insurrection can face either the death penalty or life imprisonment, the Korea Herald said. 

Cho Sung-hyun, commander of the First Security Group of the Capital Defense Command, and Kim Hyung-ki, head of the First Special Forces Battalion of the Special Warfare Command, will take the witness stand Monday, according to Yonhap. 

After being removed from the presidency, the immunity that Yoon previously enjoyed will end. This means that all kinds of incidents related to Yoon in the past may become the objects of investigation in the future, and investigations into other cases involving Yoon will also pick up speed, and may lead to further turmoil in South Korean politics, said Zhan Debin, director and professor of the Center for Korean Peninsula Studies at the Shanghai University of International Business and Economics. 

Although this is not Yoon's first court appearance, it is the first time he will attend as a defendant after leaving office, the Korea JoongAng Daily reported. He previously appeared at the court on February 20 for a pretrial hearing, which did not require his presence, and at the Seoul Western District Court on January18 for a warrant review hearing, the media report said. 

The case centered on whether Yoon broke the law by engaging in five key actions: declaring martial law, writing up a martial law decree, deploying troops to the National Assembly, raiding the National Election Commission and attempting to arrest politicians, Yonhap said in an article on April 4. 

The court recognized all of the charges, including that he did not meet the legal requirements for declaring martial law. Under the Constitution, a president can declare martial law during war or in an equivalent national emergency, Yonhap said. 

Yoon justified his action by accusing the main opposition party of paralyzing state affairs with its repeated impeachments of officials of his administration and attempt to cut the state budget. The court rejected his argument, according to the South Korean media outlet. 

Even after his dismissal, Yoon reportedly held discussions with senior figures from the People Power Party, offering his views on the upcoming presidential election and the broader political developments, fueling controversy over his continued political meddling, Yonhap said. 

Yoon's trial also exposes the polarization and fragmentation within South Korea's political arena, Xiang Haoyu, a research fellow at the China Institute of International Studies, told the Global Times, noting that if the result is unfavorable to Yoon, it will also be a blow to South Korea's conservative party. 

South Korea formally set June 3 for a snap presidential election following Yoon's ouster, Xinhua reported last week. Shortly after the announcement, Lee Jae-myung, ex-leader of South Korea's main liberal opposition Democratic Party, announced his bid for a snap presidential election via a video message.

South Korea itself does not want its political strife to affect its domestic and foreign policies. However, judging from the current situation, the period of waiting for the elections is bound to have some impact on South Korea's decision-making in key topics, said Xiang.