What to Know About South Korea President Yoon’s Impeachment Over Martial Law

South Korea’s Constitutional Court on Friday upheld the impeachment of President Yoon Suk Yeol, removing him from office four months after his short-lived imposition of martial law on Dec. 3.

Protesters who have been demanding his ouster erupted in cheers at the ruling, waving flags and pumping their fists in the air. For weeks leading up to the ruling, hundreds of thousands of people protesting for and against Mr. Yoon have lined the streets of Seoul, often enduring freezing temperatures, rain and snow.

At 11 a.m. local time, the court’s acting chief justice, Moon Hyungbae, began reading the ruling, which came after months of deliberation. Some 22 minutes later, he announced that all eight of the court’s justices had voted to remove Mr. Yoon from office. The now ex-president had “betrayed the trust of the people” and “severely violated the law,” Mr. Moon said.

“It has been a great honor for me to work for the country,” Mr. Yoon said in a statement released through his lawyers. “I and regretful and sorry that I could not live up to your expectations.”

The court ruling is effective immediately and cannot be appealed.

Why was Mr. Yoon impeached?

Late on Dec. 3, Mr. Yoon stunned the country when he declared martial law, but it lasted only six hours because lawmakers quickly voted to overturn it.

Shortly after he made the announcement on live television, troops stormed the National Assembly building under orders to “break down the door and drag out” lawmakers gathering inside to vote down the martial law decree and arrest key figures, including the speaker of the floor. Crowds of citizens confronted the troops, and some lawmakers scaled fences to get into the assembly and vote.

On the same night, Mr. Yoon also sent troops to the National Election Commission who attempted to search and confiscate its database. This violated the agency’s constitutionally guaranteed independence, the court ruled.

Delivering the ruling, Justice Moon said Mr. Yoon had abused his duties as the nation’s commander in chief. The martial law decree did not meet the constitutional requirement for a national crisis which Mr. Yoon repeatedly said was one of the reasons he had made the extraordinary declaration.

The judges said that Mr. Yoon rushed his idea for imposing martial law through a hurriedly convened Cabinet meeting on the night of Dec. 3. without proper deliberation, and that he failed to notify the National Assembly, as was required by law.

Only six of the eight members on the bench needed to vote in favor to uphold the impeachment, but the decision was unanimous.

What will happen next?

Acting president Han Duck-soo will continue in his role until the nation elects a new president through a snap election. This must take place within 60 days from Friday, meaning early June at the latest. The National Election Commission is expected to announce the date in the coming days.

Political parties will select their candidates through primary elections.

Lee Jae-myung is the expected front-runner to lead the opposition Democratic Party. He has been Mr. Yoon’s political rival since the last presidential elections in 2022 when he lost to the former president by less than 1 percent of the votes. Mr. Lee has been at the helm of the political push to remove the now-impeached president.

It’s less clear who will come out in front of the race to lead the ruling People Power Party. Its former leader, Han Dong-hoon, resigned in December after disagreement with both Mr. Yoon and his party over the martial law issue.

Oh Se-hoon, the mayor of Seoul, and Hong Joon-pyo, the mayor of Daegu, are others who have been suggested as potential candidates.