The Constitutional Court on Friday in a historic ruling upheld a decision to impeach now-former President Yoon Suk Yeol, officially removing him from office and leaving Korea without a sitting president.

The decision comes 111 days — nearly four months — after the National Assembly first voted to impeach Yoon following his sudden and short-lived declaration of martial law.

It all began on Dec. 3, 2024.On a seemingly typical Tuesday night, around 10:20 p.m., after most workers and students had returned home, President Yoon unexpectedly appeared on national broadcasts. In just a few minutes, he made an announcement that shocked the nation: he was declaring martial law.

Even before the public had time to process the news, reports broke that military forces had been deployed to block lawmakers from entering the National Assembly.

This triggered a standoff: police attempted to prevent lawmakers from entering, while 190 lawmakers scrambled to find ways into the building to vote to overturn the decree. Crowds of citizens also rushed to the National Assembly — some to protest the martial law, others in support of Yoon.

At 1:02 a.m. on Dec. 4, a quorum was reached. With 190 lawmakers present, the National Assembly unanimously voted to overturn the martial law declaration.

In his Dec. 3 address, President Yoon claimed that the country faced serious threats. He accused the opposition Democratic Party of engaging in “anti-state activities” and collaborating with “North Korean communists” to undermine the nation’s democracy and paralyze the government. He said the declaration was intended to alert the public and urge vigilance.

He also raised concerns about “anti-state forces” interfering with upcoming elections, a claim that resonated with many of his supporters.

Trial and error in National Assembly's moves to impeach Yoon

On Dec. 7, lawmakers from the liberal Democratic Party (DP) and its allies attempted to impeach Yoon, but the motion failed after a boycott by the conservative People Power Party (PPP), which prevented the 200-vote threshold required for impeachment.

However, just a week later on Dec. 14, 12 lawmakers from the PPP crossed party lines and joined the opposition, allowing the impeachment motion to pass with 204 votes.  

After the impeachment motion passed, Prime Minister Han Duck-soo became acting president. But less than two weeks later, on Dec. 27, Han himself was impeached by the National Assembly.

Why? The court typically seats nine justices, but three had recently resigned, leaving only six on the bench — the bare minimum required to rule on Yoon’s impeachment. The DP asked Han to nominate three new justices (Cho Han-chang, Chung Kye-sun and Ma Eun-hyuk), hoping to ensure a majority in favor of impeachment.

Han refused to appoint them, claiming that as acting president he did not have the authority and that both sides of the political aisle had not reached a consensus on appointing all three. The DP was not pleased — so they impeached him. As a result, Finance Minister Choi Sang-mok became the next acting president.

Yoon's Impeachment Trial Begins

On Dec. 27, the Constitutional Court held the first hearing in Yoon’s impeachment trial.Meanwhile, Acting President Choi did what Han wouldn’t: he appointed two of the three nominated justices — Cho Han-chang and Chung Kye-sun — one from each party. The third nominee, Ma Eun-hyuk, remained unappointed.

The First Sitting President to be Detained

On Dec. 31, 2024, the Seoul Western District Court issued a detention warrant for Yoon, requested by the Corruption Investigation Office for High-ranking Officials (CIO).

But detaining a president — even an impeached one — wasn’t easy. The Presidential Security Service and the 55th Guard Corps of the Army’s Capital Defense Command strongly thwarted attempts to arrest Yoon.

On Jan. 14, the first formal impeachment hearing was held — but it lasted only four minutes due to Yoon’s absence.  

On Jan. 15, Yoon surrendered, choosing to walk out of his residence rather than allow a potentially violent clash between his guards and the CIO. After 10 hours of questioning, he was transported to the Seoul Detention Center in Uiwang, Gyeonggi.

Testimonies and Mounting Legal Challenges

The second impeachment hearing was held on Jan. 16. Key witnesses were called, including former Defense Minister Kim Yong-hyun, who admitted to drafting the martial law decree, and former Defense Counterintelligence Commander Yeo In-hyung, who testified that Kim ordered the deployment of troops to the National Assembly.

On Jan. 19, the court issued a formal arrest warrant for Yoon. That same day, the courthouse was attacked by Yoon’s supporters, who broke windows, trespassed and damaged court property

Yoon finally appeared at the third hearing on Jan. 21.

Before we go dive deeper into the story, It's also important to know the key legal issues surrounding his martial law declaration:1. The suspension of National Assembly functions, undermining its constitutional role.  2. Deployment of military forces to the legislature.  3. The authorization and drafting process, with significant military involvement.

Now back to the hearings. More testimonies soon followed, including Former NIS First Deputy Director Hong Jang-won who claimed he received orders to arrest key political figures. Former Army Special Warfare Commander Kwak Jong-keun testified that Yoon directly ordered him to remove lawmakers from the Assembly. Former Acting President Han testified at the 10th hearing on Feb. 20.

All the while, Yoon’s legal team repeatedly requested the Seoul Central District Court to cancel his detention.

The final, 11th impeachment hearing was held on Feb. 25, where Yoon made his closing remarks. Yoon to the end insisted that the martial law decree was intended to warn the public about a national crisis caused by anti-state forces.

Meanwhile, the DP wasn’t done pressuring Acting President Choi Sang-mok. On Feb. 27, the Constitutional Court ruled that Choi violated the National Assembly’s authority by refusing the appointment — but as of April 4, he still had not appointed Ma. Also, he is no longer the acting president.

After over a month of detention, Yoon was released when the Seoul Central District Court ruled that prosecutors had missed the legal deadline to file an indictment.

At 11:22 a.m. on April 4, in a historic moment, the Constitutional Court upheld the National Assembly’s decision to impeach President Yoon Suk Yeol. His presidency has now come to an end.

The nation must now prepare for a presidential election, which must be held within 60 days of the ruling. Stay tuned to Korea JoongAng Daily for in-depth coverage as the future of Korea unfolds.