For six weeks, South Korea has lurched through its worst political crisis in decades, throwing the resilience of the country’s democracy into question. On Tuesday, it takes the biggest step toward a resolution, when the Constitutional Court begins deliberating whether to remove or reinstate the country’s impeached president.
The eight justices on the court will be the final arbiters on the fate of President Yoon Suk Yeol, who was impeached and suspended from office on Dec. 14 by the National Assembly for his short-lived declaration of martial law 11 days earlier.
The stakes are high. Rival groups of citizens have rallied for weeks, some in front of the court, either calling for Mr. Yoon’s ouster or demanding his return to office. Hard-liners on both sides have warned of “civil war” if the court does not rule in their favor.
If Mr. Yoon is removed, it will be another crushing blow to the country’s conservative camp: He will be the third conservative president in a row to be ousted, imprisoned or both before or after their term ended.
But if the deeply unpopular leader is allowed to return to office, it could set a precedent for future leaders to use martial law as a political tool, said Ha Sang-eung, a professor of political science at Sogang University in Seoul.
“I wonder what other democracies around the world would think of that happening in South Korea,” Mr. Ha said.
Mr. Yoon has vowed to triumph at the Constitutional Court. But his lawyers have said he will not attend the first hearing on Tuesday, citing fears that criminal investigators might try to detain him for questioning on insurrection charges if he leaves his fortified residence in central Seoul. His absence is expected to cut the Tuesday hearing short. But the court can proceed with its deliberations from the second hearing, set for Thursday — with or without him.
“President Yoon will defend himself at court as often as is necessary,” said his lawyer, Yoon Kab-keun.
Mr. Yoon’s martial law lasted only six hours after being voted down by lawmakers in the opposition-led National Assembly. But his attempt to put South Korea under military rule for the first time in four decades has unleashed a prolonged political uncertainty in a key ally of the United States, which has expressed concern over Mr. Yoon’s move.
While Mr. Yoon faces a parallel criminal investigation on charges of insurrection, the focus for resolving his presidency now shifts to the Constitutional Court: Its decision could help dispel some of that uncertainty, or it could add to the turmoil if its decision angers the public.
As the country’s political polarization has deepened in recent years, the court has handled a growing number of cases only it can settle: officials, prosecutors and judges impeached by the National Assembly. Mr. Yoon is the third South Korean president in the past two decades to be impeached.
In 2004, President Roh Moo-hyun was impeached by the National Assembly for violating election law, but he was reinstated by the court, which ruled that his offense was not serious enough. In 2017, the court ousted Park Geun-hye, another impeached president, for corruption and abuse of power.
“When the country is drifting without a skipper or without knowing who the skipper is, the Constitutional Court sets it back on course,” said Jung Ji Ung, a lawyer and president of a bar association for Gyeonggi, the populous province that surrounds Seoul.
South Korea has a separate Supreme Court, but it created the Constitutional Court in 1987 as the ultimate interpreter of its Constitution. Located in Seoul’s quiet old town, the court has often attracted rival activists holding banners and loudspeakers when it neared historic verdicts.
In 2005, it abolished a centuries-old practice of allowing children to adopt only their father’s family name. In 2009, it voted against a ban on nighttime protest rallies, allowing citizens to gather after hours to express their grievances, as they have in recent months for and against Mr. Yoon. In 2015, the court decriminalized adultery. In 2019, it struck down a 66-year-old law that made abortion a crime punishable by up to two years in prison.
As the number of impeachment cases grows, the court has become more politically important and so have its nine justices, who each serve a term of six years. Three are chosen by the president, three by the chief justice of the Supreme Court and three by the political parties.
The current court has eight justices, and one vacancy. Two were selected by Mr. Yoon and his party; three by the former and current Supreme Court chief justices; and three by Mr. Yoon’s predecessor, Moon Jae-in, and his Democratic Party, the current opposition.
Mr. Yoon can be removed from office if six or more justices agree he should be, but he might not be able to rely on partisanship in the court to save him. In the past, the justices have not always voted based on who backed their appointments: The court ruled unanimously to remove Ms. Park, even though some of them had been appointed by her or her party.
The court’s ruling will depend on the gravity of any constitutional and legal offenses found to be committed by Mr. Yoon, said Bang Seung-Ju, a professor at Hanyang University School of Law in Seoul. It will also weigh whether a decision not to expel him would pose a greater disadvantage to the constitutional order and national interest than would his removal, such as by furthering political instability, he said.
Prosecutors to the court are appointed by the National Assembly and say that Mr. Yoon committed insurrection when he sent armed troops into the Assembly, ordering them to seize the parliament and detain his political enemies. Since he took office in 2022, Mr. Yoon has been locked in a standoff with the National Assembly, which he called “a den of criminals” when justifying his martial law decree.
Mr. Yoon also violated the Constitution by banning all political activities and placing the news media under military control, prosecutors say.
State prosecutors have already arrested a former defense minister and several military generals on charges of helping Mr. Yoon commit insurrection. Mr. Yoon ordered the generals to break down the doors at the National Assembly, “by shooting if necessary,” and “drag out” lawmakers, the prosecutors said.
Mr. Yoon Kab-keun, the president’s lawyer, called those testimonies “corrupted.”
But legal analysts including Noh Hee-bum, a former research judge at the Constitutional Court, expect the court to unseat Mr. Yoon as early as February, in order to help ease the country’s political uncertainty and because there is enough evidence against him.
“It’s a matter of time,” Mr. Noh said.
