The criminal trial of South Korea’s former president, Yoon Suk Yeol, began on Monday as he faces charges of insurrection for declaring martial law late last year, which led to months of political unrest.

The martial law declaration lasted just six hours after parliamentary staffers blocked special forces from entering the parliament building, where lawmakers voted against it.

Yoon, who left his home in a motorcade to attend the court session at the Seoul Central District Court, denied all charges. Prosecutors argued that he had no legal right to declare martial law and accused him of attempting to paralyze state institutions like parliament.

Yoon defended his actions, claiming that martial law was necessary to highlight the opposition party’s control over the legislature, which repeatedly blocked his government’s agenda. He maintained that he never intended to disrupt the country.

The charge of insurrection could result in life imprisonment or even the death penalty, though South Korea has not carried out executions in decades.

Earlier this month, Yoon was removed from office by the Constitutional Court for violating constitutional powers, with his martial law declaration on December 3 which is a serious blow to democracy. The court notes that his actions caused chaos across society, the economy, and foreign policy.