South Korea’s impeached former president Yoon Suk Yeol denied charges of insurrection Monday as he appeared in court for the first day of his criminal trial over a failed martial law declaration late last year.

Yoon, who was formally removed from office earlier this month, is accused of attempting to subvert civilian rule by deploying armed soldiers to the National Assembly on 3 December in a bid to impose martial law. The move led to his impeachment and suspension by lawmakers, followed by his arrest in January. He was later released on procedural grounds.

The former leader appeared at Seoul Central District Court, where he confirmed his identity before the panel of judges. Yoon, a former prosecutor, rejected the charges from the stand and challenged the prosecution’s case point-by-point using court monitors to display their presentation, according to pool reports.

"To frame an event that lasted only a few hours, was non-violent, and immediately accepted the dissolution request from the National Assembly as insurrection... strikes me as legally unfounded," Yoon told the court.

Prosecutors argued that Yoon’s actions were part of a premeditated plan to “incite an uprising with the intent to subvert the constitutional order.” They cited military deployment orders to the parliament, which allegedly included instructions to break windows and cut power.

The court is expected to hear testimony from two military officers, including one who claims he was ordered to remove lawmakers from the National Assembly to enforce the martial law declaration.

On the day of the attempted takeover, lawmakers defied the military’s presence, climbing over fences to enter parliament and vote against Yoon’s declaration, effectively forcing him to reverse the decision within hours.

Legal experts say the trial is likely to be protracted.

"The first verdict is likely to be delivered around August, but the case involves around 70,000 pages of evidence and numerous witnesses. So if deemed necessary by the court, the trial may be extended," lawyer Min Kyoung-sic told AFP.

If convicted, Yoon would become the third South Korean president found guilty of insurrection, following two former military rulers involved in the country’s 1979 coup. The charges carry a maximum sentence of death or life imprisonment, though South Korea has observed a moratorium on executions since 1997.

The high-profile case draws parallels to former President Park Geun-hye’s impeachment in 2016. Her final sentence for corruption was upheld by the Supreme Court in 2021, more than four years after her removal from office.