Protesters gathered by the tens of thousands on Saturday in Seoul, divided into two camps that reflected a nation divided over its embattled president.
One crowd shouted for the country’s top court to remove Yoon Suk Yeol, calling him “a ringleader of insurrection.” Separated from them by walls of polices buses, another crowd chanted for him to be restored to office, with speakers calling his parliamentary impeachment fraudulent and warning of civil war if he was ousted.
Never have the jitters run so high in South Korea before a court ruling as the country waits impatiently for the Constitutional Court to decide whether to uphold or reject the impeachment of Mr. Yoon. The walls of the court have been fortified with razor wire as the eight justices prepare the ruling, which could shape the future of the country’s democracy.
The decision could help bring an end to the months of political turmoil Mr. Yoon unleashed on Dec. 3 with his failed attempt to place his country under martial law. Or it could push the country into a deeper political crisis.
South Koreans have grown weary of the prolonged political uncertainty and want the court to decide. But it has kept them on edge for weeks, giving no hint when its justices will deliver probably the most consequential ruling of their careers.
As the deliberations dragged on, conspiracy theories abounded and speculation flourished. Some suggested that the court was irreparably split. (The votes of at least six of the eight justices are needed to remove Mr. Yoon. Otherwise, he will be reinstated.) Others said it was just taking time to make its historic ruling watertight.
“The country is at a crossroads,” said Cho Gab-je, a prominent South Korean journalist and publisher who has covered the nation’s political evolution since 1971. “If the court reinstalls Yoon in office despite what he did, it will give future leaders of the country a license to rule by martial law. South Korea will become a banana republic.”
The political instability Mr. Yoon set off has left his country without an elected leader at a time when North Korea is escalating its nuclear threat and strengthening military ties with Russia. Although South Korea is one of America’s key allies, its leader has yet to meet President Trump while leaders of other nations, including Japan, have.
In February, the Economist Intelligence Unit’s Democracy Index 2024 downgraded South Korea from a “full” to a “flawed democracy.”
Mr. Yoon’s martial law lasted only six hours but provoked fury among many South Koreans. The National Assembly impeached him on Dec. 14, suspending him from office. If Mr. Yoon is removed, South Korea will elect a new president within 60 days.
Polls in recent weeks showed that South Koreans preferred Mr. Yoon’s ouster to his reinstatement roughly three to two. But in a deeply divided nation, Parliament’s decision to impeach him has also galvanized the political right.
On Saturday, tens of thousands of Christian churchgoers, military veterans and other mostly older people occupied the main boulevard in central Seoul, many sitting in neat rows of plastic chairs, holding signs that called for Mr. Yoon’s reinstatement.
A parade of Christian pastors spoke from a raised platform, promising that Mr. Yoon “will return to office with spring winds.”
“Hallelujah!” the crowd erupted.
As one pastor urged the participants to show “thanks to God” for protecting Mr. Yoon, church staff members in orange vests passed through the crowd with blue bags for church donations.
“If President Yoon is not reinstated, there will be a civil war,” warned Jun Kwang-hoon, a firebrand pastor who has organized large pro-Yoon conservative rallies, calling his campaign a “patriotic” war against “Communist reds.”
Mr. Jun led his followers in a song that has become their protest anthem. “There is nothing wrong with my age,” the song’s upbeat refrain declared, prompting many to get up from their chairs and dance. “It’s a perfect age to be patriots.”
In another part of the city center, on the other side of the walls of police buses, a younger and livelier crowd gathered, holding signs like, “A new spring, a new country!” or “Here is the ruling, Yoon Suk Yeol: You are fired!”
Batteries of loudspeakers throbbed with a song whose refrain has become a catchphrase for those who want Mr. Yoon ousted. “All state authority shall emanate from the people,” it went, citing a line from the Constitution.
Led by speakers, the crowd chanted: “The Constitutional Court, remove Yoon Suk Yeol immediately. It’s an order from the people.”
The anti-Yoon crowd included people who marched behind dozens of whimsical signs, like “The national association of tea-drinkers” and “A group of people who study cats’ paws.” But they, like their pro-Yoon counterparts, said that they were anxious about why the court was taking so long to rule, and they expressed fear that the decision might not be what they wanted.
“The day Yoon Suk Yeol declared martial law, I was scared,” said Han Ye-jin, a college student. “Now, I am desperate.”
No matter what it decides, the court will anger a large portion of the society. People on both sides have shaved their heads or gone on hunger strike to press their demands.
“If it endorses Yoon’s impeachment, there will be some commotion, but the political landscape will quickly shift toward a presidential election,” said Shang E. Ha, a professor of political science at Sogang University in Seoul. “But if he returns to office, even those who have been waiting patiently for a ruling will take to the streets. We will see riots.”
In January, scores of Yoon supporters vandalized a Seoul district courthouse after a judge there issued a warrant to arrest him on an insurrection charge. Two supporters of Mr. Yoon died after setting themselves on fire to protest his impeachment.
The police are preparing for the worst. Schools, street vendors and a former royal palace in the neighborhood of the Constitutional Court will close on the day of ruling. The authorities also called for the removal of rocks, empty bottles, trash bins — anything that could be a weapon — from the streets. About 14,000 police officers were ready to deploy. Drones have been banned from flying over the courthouse, and all 86,000 privately owned guns in the country must be kept locked in police stations.
The police also assigned bodyguards to Lee Jae-myung, the main opposition leader, after his party reported anonymous assassination threats. Officers have escorted the eight justices on their commute to and from the court.
“I urge the people to respect and accept whatever the court decides,” said Finance Minister Choi Sang-mok, the country’s acting president, while expressing concern over the potential for violent clashes.