South Korea has been thrown into political turmoil since Yoon, a conservative, declared martial law on Dec. 3 and sent hundreds of troops to the liberal opposition-controlled National Assembly and other places in Seoul. Yoon’s decree lasted only six hours as enough lawmakers managed to enter an assembly hall where they quickly voted down the decree.

The impeachment arguments

The assembly impeached Yoon on Dec. 14, alleging he violated the Constitution and other laws by suppressing assembly activities and trying to detain politicians. Yoon’s impeachment made Han acting president until he was impeached in late December.

The unprecedented, successive impeachments that suspended the country’s top two officials intensified domestic division and deepened worries about South Korea’s diplomatic and economic activities.

South Korean acting President Han Duck-soo speaks during a briefing at the Government Complex in Seoul, South Korea, on March 24, 2025. (AP Photo/Ahn Young-joon, Pool)

A major trigger for the opposition’s push to impeach Han was his refusal to fill three vacant seats at the Constitutional Court’s nine-member bench. That was a highly explosive issue because the court needed support from at least six justices to approve Yoon’s impeachment and filling its empty posts could make such a decision more likely.

After Han was suspended, his successor as acting president, Choi Sang-mok, appointed two new justices but left the ninth seat vacant.

Han was also accused in the impeachment motion of abetting Yoon’s martial law declaration and obstructing efforts to open independent investigations into Yoon’s alleged rebellion in connection with his martial law decree.

On Monday, seven of the Constitutional Court’s eight justices ruled to overturn or dismiss Han’s impeachment. They ruled that his alleged actions weren’t against the law or weren’t serious enough to remove him from office or his impeachment motion didn’t even meet a required quorum when it passed through the assembly. One justice upheld Han’s impeachment.

The main liberal opposition Democratic Party expressed regret over the court’s decision to reinstate Han and urged it to dismiss Yoon quickly. Yoon’s office welcomed Monday’s ruling, saying it shows again the opposition’s repeated uses of impeachment motions were “reckless, malicious political offensive.”

What’s next?

Observers earlier had predicted the Constitutional Court would rule on Yoon’s case in mid-March, but it hasn’t done so, sparking varied speculation on possible reasons.

“Today’s verdict will give hope to Yoon’s supporters for a similar fate and hope for Yoon’s opponents for his ouster,” said Duyeon Kim, a senior analyst at the Center for a New American Security in Washington. “But it’s too soon to predict the court’s verdict on Yoon because the specific details of both cases and allegations are different.”

Kim said the reinstatement of Han, a career bureaucrat, will bring more stability to South Korea compared to when his powers as acting president were suspended.

Massive rival rallies backing or denouncing Yoon have divided the streets of Seoul and other major cities in South Korea. Earlier surveys showed that a majority of South Koreans were critical of Yoon’s martial law enactment, but those supporting or sympathizing with Yoon have later gained strength.

Yoon argues that his martial law introduction was a desperate attempt to bring attention to the “wickedness” of the Democratic Party which obstructed his agenda and filed many impeachment motions against senior officials. Yoon critics counter he likely tried to use military rule to frustrate possible special investigations into scandals involving him and his wife.

Senior military and police officers sent to the assembly have said that Yoon ordered them to drag out lawmakers to prevent a floor vote to overturn his decree. Yoon says the troops’ deployment was designed to maintain order.

If the court upholds Yoon’s impeachment, South Korea must hold a presidential election to choose his successor. If it rules for him, Yoon will regain his presidential powers.

Yoon has separately been charged with directing rebellion, a charge that carries the death penalty or a life sentence if he is convicted.