A South Korean police officer stands in front of the Constitutional Court in Seoul, South Korea on Tuesday (December 17, 2024).
| Photo Credit: AP

South Korea’s acting leader vowed Tuesday (December 17, 2024) to convey to the world that things are back to normal following parliament’s impeachment of conservative President Yoon Suk Yeol, but rival parties began squabbling over the mechanics of a court ruling to determine whether to formally unseat or reinstate him.

The country’s liberal opposition-controlled parliament voted to impeach Mr. Yoon last Saturday (December 14, 2024) over his short-lived December 3 martial law imposition, suspending his presidential powers until the Constitutional Court determines whether to uphold or overturn the decision. If Mr. Yoon is dismissed, a national election must be held to pick his successor within two months.

Prime Minister Han Duck-soo, who became acting leader, has taken steps to reassure the US and other countries and stabilise markets. Presiding over a Cabinet Council meeting on Tuesday (December 17, 2024), Mr. Han said he will “continuously do my utmost to inform the international society that the Republic of Korea is fast regaining stability and maintain confidence with partners.”

But the country’s intense political strife appears to be far from over, as the rival parties began bickering over whether to fill three vacant justices’ seats at the Constitutional Court.

To formally end Mr. Yoon’s presidency, the nine-member court panel needs support from at least six justices. But since three seats remain vacant following retirements, a unanimous decision in favour of Mr. Yoon’s impeachment is required to throw him out of office for good.

Three of the court’s nine justices are directly appointed by the president. Three others are nominated by the Supreme Court head and another three by the National Assembly, and their formal appointments by the president has widely been a formality. The three seats that are currently open are to be nominated by the National Assembly – two by the Democratic Party and the other by Mr. Yoon’s ruling People Power Party.

The court can rule on Mr. Yoon’s case only with the current six justices. But the main liberal opposition Democratic Party, which led the impeachment efforts against Mr. Yoon, has said it would speed up the process of restoring the court’s nine-justice system to promote fairness and public confidence in its ruling.

But PPP floor leader Kweon Seong-dong, a Mr. Yoon loyalist, created a stir Tuesday (December 17, 2024) as he voiced his objection to a Democratic Party push to fill the three vacancies. He said it would be inappropriate for Mr. Han, the acting leader, to appoint justices nominated by parliament, saying such authorities solely rest with the president.

“An acting president can appoint Constitutional Court justices when there is a presidential vacancy, but not when the president’s duties are just suspended,” Kweon said.

Many observers say the court’s current six-member configuration is advantageous for Mr. Yoon’s chances to return to office, as it would only require a single justice rejecting the parliament impeachment. They note Cheong Hyungsik, one of the six justices, is a clear conservative who was directly appointed by Mr. Yoon.

The Democratic Party quickly dismissed Kweon’s argument as “absurd and utterly nonsensical” and urged PPP to abide by a November agreement between the rival parties to nominate the three Constitutional Court justices.

Party lawmaker and spokesperson Jo Seoung-lae said PPP has “blatantly revealed their true intention to obstruct the constitutional trial.”

There was no immediate response from Mr. Han, who during the Cabinet meeting stressed that the government would cooperate with the ruling and opposition parties to stabilize the economy.

There is no clear definition about what an acting president can and cannot do over the appointments of court justices. The Democratic party accuses PPP of trying to drag out the impeachment trial at the Constitutional Court, which has up to 180 days to determine Mr. Yoon’s fate.

Time is a crucial issue for Democratic Party leader Lee Jae-Myung, who is favoured by polls to win a presidential by-election in the event of Mr. Yoon’s ouster but grapples with his own legal troubles. Lee could possibly be prohibited from running for president if the appellate and Supreme courts uphold his lower court conviction for election law violation in November.

Mr. Yoon faces allegations of rebellion and abuse of power over his martial law introduction. Investigative authorities want him to appear for questioning later this week, but officials at Mr. Yoon’s office and residence on Monday (December 16, 2024) refused to receive requests for his appearance.

The martial law declaration, the first of its kind in more than 40 years, drew hundreds of troops who tried to encircle parliament and prevent lawmakers from voting on the decree. Many lawmakers still managed to get inside a National Assembly chamber and voted to overturn Mr. Yoon’s decree unanimously, forcing Mr. Yoon’s Cabinet to lift it.

Mr. Yoon’s decree, which harkened back to an era of past military-backed dictatorships, has sparked massive street protests calling for his ouster and resulted in his approval rating plummeting. Mr. Yoon’s defence minister, police chief and several other senior military commanders have been arrested over their roles in the martial law enforcement.

Supporters of Mr. Yoon worry that his early exit would severely hamper the country’s conservatives and cause them to likely lose a presidential by-election to the liberals as they did in 2017 when then-impeached conservative President Park Geun-hye was ousted and arrested over a corruption scandal.

A participant holds a paper during a rally to demand South Korean President Yoon Suk Yeol’s impeachment outside the National Assembly in Seoul, South Korea, on December 13, 2024.
| Photo Credit: AP

A defiant South Korean President Yoon Suk Yeol faces a second impeachment vote on Saturday (December 14, 2024) over his short-lived attempt to impose martial law, a move that shocked the country, split his party and imperilled his presidency half way through his term.

His move to impose military rule on December 3 was rescinded barely six hours later after parliament defied troops and police to vote against the decree, but it plunged the country into a constitutional crisis and triggered widespread calls for him to step down for breaking the law.

Opposition parties plan to hold an impeachment vote at 4 p.m. (12.30 p.m. IST) on Saturday, with large demonstrations planned ahead of the vote.

First impeachment failed

Mr. Yoon’s conservative People Power Party boycotted the first impeachment vote a week earlier, preventing a quorum.

Since then, PPP leader Han Dong-hoon has urged party members to vote for impeachment on Saturday, and at least seven PPP members have said they would vote to impeach.

The opposition parties control 192 of the 300 seats in the single-chamber parliament so they need at least eight PPP votes to reach the two-thirds threshold for impeachment.

Ahn Cheol-soo, a PPP lawmaker among those backing Mr. Yoon’s impeachment, said in a Facebook post on Saturday that he would vote for impeachment “for the sake of swift stabilisation of people’s livelihood, economy and diplomacy.”

The PPP floor leader said on Friday, however, that the party’s stance is still to oppose impeachment.

PPP lawmakers are due to meet on Saturday morning to decide whether to change that position.

If impeached, Mr. Yoon would lose authority but remain in office until the Constitutional Court either removes or reinstates him. In the meantime, Prime Minister Han Duck-soo would serve as acting president.

If the court removes Mr. Yoon or he resigns, a presidential election must be held within 60 days.

Mr. Yoon is separately under criminal investigation for alleged insurrection over the martial law declaration and authorities have banned him from travelling overseas.

He has not signalled a willingness to resign and in a speech on Thursday vowed he would “fight to the end” and defended the martial law decree as necessary to overcome political deadlock and protect the country from domestic politicians who are undermining democracy.

Mr. Yoon, president of Asia’s fourth-largest economy, hopes political allies will rally to support him, but the fiery remarks appeared to find mixed reception among PPP lawmakers.

A Gallup Korea poll on Friday had two-thirds of supporters of Mr. Yoon’s party opposing the impeachment, though three-quarters of all respondents supported it.

Elected in 2022, Mr. Yoon was widely welcomed in Washington and other Western capitals for his rhetoric defending global democracy and freedom, but critics said that masked growing problems at home.

He clashed with opposition lawmakers that he has labelled as “anti-state forces” and press freedom organisations have criticized his heavy-handed approach to media coverage that he deems negative.

The crisis and ensuing uncertainty shook financial markets and threatened to undermine South Korea’s reputation as a stable, democratic success story.

South Korean shares rose for a fourth straight session on Friday on hopes that the political uncertainty would ease after this weekend’s parliamentary impeachment vote.

A person pushes an effigy in a cage during a rally calling for the impeachment of South Korean President Yoon Suk Yeol, who declared martial law, which was reversed hours later, in Seoul, South Korea, December 12, 2024.
| Photo Credit: REUTERS

South Korea’s Parliament says the country’s six opposition parties have submitted a new joint motion to impeach President Yoon Suk Yeol over his declaration of martial law.

The National Assembly said the main Opposition Democratic Party and five smaller Opposition parties submitted the impeachment motion on Thursday (December 12, 2024) afternoon.

The parties say they aim put the motion to a floor vote on Saturday (December 14, 2024).

Mr. Yoon’s short-lived Dec. 3 martial law declaration has triggered political chaos and large protests calling for his ouster. The Democratic Party has argued that Mr. Yoon’s decree amounted to rebellion.

Earlier Thursday, Mr. Yoon defended his decree as an act of governance and denied rebellion charges.

If Mr. Yoon is impeached, his presidential powers would be suspended until the Constitutional Court decides whether to remove him from office or restore his powers. If he is dismissed, a new presidential election would be required within 60 days.

Protesters wear masks depicting South Korean President Yoon Suk Yeol, outgoing Defense Minister Kim Yong-hyun, People Power Party’s leader Han Dong-hoon and Choo Kyung-ho at a rally calling for the impeachment of South Korean President Yoon Suk Yeol, who declared martial law, which was reversed hours later, near the National Assembly in Seoul, South Korea, December 7, 2024.
| Photo Credit: Reuters

South Korea’s former Defence Minister was arrested Sunday (December 8, 2024), local media reported, a day after President Yoon Suk Yeol survived an impeachment vote over his calamitous attempt to impose martial law.

The motion failed due to a boycott of the vote by Mr. Yoon’s party, even though huge crowds braved freezing temperatures in another night of protests outside parliament in Seoul to demand the President’s ouster.

Kim Yong-hyun had already resigned as Defence Minister after the brief suspension of civilian rule late on Tuesday by Mr. Yoon that saw soldiers and helicopters sent to parliament.

Mr. Yoon was forced to rescind the order hours later and parliament voted down his decree.

Mr. Kim had already been slapped with a travel ban.

Police have launched an investigation into Mr. Yoon, Mr. Kim and others for alleged insurrection.

The prosecutors’ office was not immediately available for comment on Mr. Kim’s arrest, reported by the Yonhap news agency and other local media outlets Sunday morning.

Boycott

Opposition parties proposed the impeachment motion, which needed 200 votes in the 300-member parliament to pass, but a near-total boycott by Mr. Yoon’s People Power Party (PPP) doomed it to failure.

The PPP said after the vote that it had blocked the impeachment to avoid “severe division and chaos”, adding that it would “resolve this crisis in a more orderly and responsible manner”.

Party leader Han Dong-hoon said that the party had “effectively obtained” Yoon’s promise to step down, and said until this happened he would “be effectively excluded from his duties”, leaving the Prime Minister and party to manage state affairs.

The failure of the impeachment motion came as a huge blow to the massive crowds — numbering 150,000 according to police, one million according to organisers — demonstrating outside parliament.

National Assembly speaker Woo Won-shik called the PPP’s walkout “a failure to engage in the democratic process” on the part of the ruling party.

“Even though we didn’t get the outcome we wanted today, I am neither discouraged nor disappointed because we will get it eventually,” protester Jo Ah-gyeong, 30, said Saturday.

“I’ll keep coming here until we get it,” she told AFP.

‘Politically dead’

The opposition has already vowed to try to impeach Mr. Yoon again as soon as Wednesday, and many protesters vowed to continue demonstrations next weekend.

“I will impeach Yoon Suk Yeol, who has become the worst risk for South Korea, at any cost,” opposition leader Lee Jae-myung said.

Before the vote, Mr. Yoon, 63, had apologised for the turmoil but said he would leave it to his party to decide his fate.

“I caused anxiety and inconvenience to the public. I sincerely apologise,” he said in the televised address, his first public appearance in three days.

He said he would “entrust the party with measures to stabilise the political situation, including my term in office”.

The backing of PPP lawmakers came despite party head Han — who was allegedly on an arrest list on Tuesday night — saying Mr. Yoon must go.

Only three PPP lawmakers — Ahn Cheol-soo, Kim Yea-ji and Kim Sang-wook — voted in the end.

The failure of the impeachment motion “means a more protracted political crisis,” Vladimir Tikhonov, professor of Korean Studies at the University of Oslo, told AFP.

“We will have a politically dead President — basically unable to govern any longer — and hundreds of thousands coming to the streets every week until Mr. Yoon is removed,” he said.

A screen in Seoul shows footage of South Korean President Yoon Suk Yeol delivering an address to the nation on December 7, 2024
| Photo Credit: Getty Images

South Korea’s president apologised Saturday (December 7, 2024) for public anxiety caused by his short-lived attempt to impose martial law earlier this week hours ahead of a parliamentary vote on impeaching him.

Mr. Yoon said in a brief televised address Saturday morning he would not shirk legal or political responsibility for the declaration and promised not to make another attempt to impose it. He said he would leave it to his conservative political party to chart a course through the country’s political turmoil, “including matters related to my term in office.”

South Korean lawmakers are set to vote later Saturday on impeaching President Yoon Suk Yeol over his short-lived attempt to impose martial law, as protests grew nationwide calling for his removal.

ALSO READ | Timeline of South Korea’s martial law declaration

It wasn’t immediately clear whether the motion submitted by opposition lawmakers would get the two-thirds majority required for Mr. Yoon to be impeached. But it appeared more likely after the leader of Mr. Yoon’s own party on Friday called for suspending his constitutional powers, describing him as unfit to hold the office and capable of taking more extreme action, including renewed attempts to impose martial law.

Support required for impeachment

Impeaching Mr. Yoon would require support from 200 of the National Assembly’s 300 members. The opposition parties that jointly brought the impeachment motion have 192 seats combined.

That means they would need at least eight votes from Mr. Yoon’s People Power Party. On Wednesday, 18 members of the PPP joined a vote that unanimously cancelled martial law 190-0 less than three hours after Mr. Yoon declared the measure on television, calling the opposition-controlled parliament a “den of criminals” bogging down state affairs. The vote took place as hundreds of heavily-armed troops encircled the National Assembly in an attempt to disrupt the vote and possibly to detain key politicians.

Parliament said Saturday that it would meet at 5 p.m. It will first vote on a bill appointing a special prosecutor to investigate influence peddling allegations surrounding Mr. Yoon’s wife, and then on impeaching Mr. Yoon.

EDITORIAL | Costly miscalculation: On the South Korean President’s announcement of martial law

The turmoil resulting from Mr. Yoon’s bizarre and poorly-thought-out stunt has paralysed South Korean politics and sparked alarm among key diplomatic partners, including neighbouring Japan and Seoul’s top ally the United States, as one of the strongest democracies in Asia faces a political crisis that could unseat its leader.

Opposition lawmakers claim that Mr. Yoon’s martial law declaration amounted to a self-coup and drafted the impeachment motion around rebellion charges.

PPP opposes impeachment

The PPP decided to oppose impeachment at a lawmakers’ meeting, despite pleas by its leader Han Dong-hun, who isn’t a lawmaker and has no vote.

Following a party meeting on Friday, Mr. Han stressed the need to suspend Mr. Yoon’s presidential duties and power swiftly, saying he “could potentially put the Republic of Korea and its citizens in great danger.”

Mr. Han said he had received intelligence that during the brief period of martial law Mr. Yoon ordered the country’s defense counterintelligence commander to arrest and detain unspecified key politicians based on accusations of “anti-state activities.”

Hong Jang-won, first deputy director of South Korea’s National Intelligence Service, later told lawmakers in a closed-door briefing that Mr. Yoon called after imposing martial law and ordered him to help the defence counterintelligence unit to detain key politicians. The targeted politicians included Han, opposition leader Lee Jae-myung and National Assembly speaker Woo Won Shik, according to Kim Byung-kee, one of the lawmakers who attended the meeting.

The Defence Ministry said it had suspended the defence counterintelligence commander, Yeo In-hyung, who Mr. Han alleged had received orders from Mr. Yoon to detain the politicians. The ministry also suspended Lee Jin-woo, commander of the Capital Defense Command, and Kwak Jong-geun, commander of the Special Warfare Command, over their involvement in enforcing martial law.

Former Defense Minister Kim Yong Hyun, who has been accused of recommending Mr. Yoon to enforce martial law, has been placed under a travel ban and faces an investigation by prosecutors over rebellion charges.

Vice Defence Minister Kim Seon Ho, who became acting defence minister after Mr. Yoon accepted Kim Yong Hyun’s resignation on Thursday, has testified to parliament that it was Kim Yong Hyun who ordered troops to be deployed to the National Assembly after Mr. Yoon imposed martial law.

South Korea’s ruling People Power Party leader Han Dong-hun, right, speaks during a press conference at the National Assembly in Seoul, South Korea, on December 6, 2024.
| Photo Credit: AP

South Korea’s governing party chief expressed support Friday (December 6, 2024) for suspending the constitutional powers of President Yoon Suk Yeol for imposing martial law this week, in a bombshell reversal that makes Mr. Yoon’s impeachment more likely.

Opposition parties are pushing for a parliamentary vote on Mr. Yoon’s impeachment on Saturday (December 7, 2024), calling his short-lived martial law declaration an “unconstitutional, illegal rebellion or coup.” But they need support from some members of the president’s People Power Party to get the two-thirds majority required to pass the impeachment motion.

ALSO READ | Timeline of South Korea’s martial law declaration

The turmoil resulting from Mr. Yoon’s nighttime martial law decree has frozen South Korean politics and caused worry among neighbours, including fellow democracy Japan, and Seoul’s top ally, the United States, as one of the strongest democracies in Asia faces a political crisis that could unseat its leader.

During a party meeting, PPP leader Han Dong-hun stressed the need to suspend Mr. Yoon’s presidential duties and power swiftly, saying he poses a “significant risk of extreme actions, like reattempting to impose martial law, which could potentially put the Republic of Korea and its citizens in great danger.”

Mr. Han said he had received intelligence that Mr. Yoon had ordered the country’s defence counterintelligence commander to arrest and detain unspecified key politicians based on accusations of “anti-state activities” during the brief period martial law was in force.

“It’s my judgment that an immediate suspension of President Yoon Suk Yeol’s official duties is necessary to protect the Republic of Korea and its people,” Mr. Han said.

Mr. Han earlier said he would work to defeat the impeachment motion even though he criticised Mr. Yoon’s martial law declaration as “unconstitutional.” Mr. Han said there was a need to “prevent damage to citizens and supporters caused by unprepared chaos.”

Protests in Seoul

Thousands of protesters have marched in the streets Seoul since Wednesday, calling for Mr. Yoon to resign and be investigated. Thousands of autoworkers and other members of the Korean Metal Workers’ Union, one of the country’s biggest umbrella labor groups, have started hourly strikes since Thursday to protest Mr. Yoon. The union said its members will start on indefinite strikes beginning on December 11 if Mr. Yoon was still in office then.

EDITORIAL | Costly miscalculation: On the South Korean President’s announcement of martial law

Impeaching Mr. Yoon would require support from 200 of the National Assembly’s 300 members. The opposition parties who jointly brought the impeachment motion have 192 seats combined. PPP has 108 lawmakers.

In a televised statement, South Korean Vice Defense Minister Kim Seon Ho promised the ministry’s “active cooperation” with an investigation by prosecutors into the military’s role in Mr. Yoon’s martial law enforcement. He said military prosecutors will also be involved in the probe. He denied media speculation that Yoon and his military confidantes might consider imposing martial law a second time.

“Even if there’s a demand to enforce martial law, the Ministry of Defence and the Joint Chiefs of Staff will absolutely not accept it,” Mr. Kim said.

Defence Minister recommended martial law

Mr. Kim became the acting defence minister after Mr. Yoon’s office on Thursday accepted the resignation of Defense Minister Kim Yong Hyun, who has been hit with a travel ban and faces an investigation over his role in Yoon’s imposition of martial law.

Opposition parties and Mr. Han allege that it was Kim Yong Hyun who recommended that Mr. Yoon take the step. During a parliamentary hearing on Thursday, Kim Seon Ho said Kim Yong Hyun also ordered troops to be deployed to the National Assembly after Yoon imposed martial law.

Mr. Han was previously regarded as a close associate of Mr. Yoon as they spent years working together as prosecutors and he served as Mr. Yoon’s first justice minister. But after Mr. Han entered party politics and became PPP leader, their ties soured badly as they differed over how to handle scandals involving Yoon and his wife.

Mr. Han leads a minority faction within the ruling party, and 18 lawmakers in his faction voted with opposition lawmakers to overturn Mr. Yoon’s martial law decree. Martial law ultimately lasted about six hours, after the quick overrule by the National Assembly forced Mr. Yoon’s Cabinet to lift it before daybreak Wednesday.

What happens if Yoon is impeached

If Mr. Yoon is impeached, he would be suspended until the Constitutional Court rules on whether to remove him from office or restore his presidential power. Prime Minister Han Duck-soo, the country’s No. 2 official, would take over presidential responsibilities.

The main liberal opposition Democratic Party leader Lee Jae-myung said in a televised speech Friday that it was crucial to suspend Mr. Yoon as “quickly as possible.”

Mr. Lee said Mr. Yoon’s martial law enforcement amounted to “rebellion and also a self-coup.” He said Mr. Yoon’s move caused serious damage to the country’s image and paralysed foreign policy, pointing to criticism from the Biden administration and foreign leaders canceling their visits to South Korea.

Protesters are blocked by police officers as they try to march to the presidential office after a candlelight vigil against South Korean President Yoon Suk Yeol in Seoul, South Korea, Wednesday, Dec. 4, 2024.
| Photo Credit: AP

South Korea’s President accepted the resignation of his Defence Minister on Thursday (December 5, 2024) as opposition parties moved to impeach both men over the stunning yet short-lived imposition of martial law that brought armed troops into Seoul streets.

The main opposition Democratic Party and other small opposition parties submitted a joint motion to impeach President Yoon Suk Yeol on Wednesday over his martial law declaration the previous night. Martial law lasted about six hours, as the National Assembly quickly voted to overrule the President, forcing his Cabinet to lift it before daybreak Wednesday.

On Thursday, Mr. Yoon replaced Defence Minister Kim Yong Hyun with Choi Byung Hyuk, a retired four-star general who is South Korea’s ambassador to Saudi Arabia, Mr. Yoon’s office said.

It didn’t provide any further comments by Mr. Yoon. He hasn’t made any public appearances since he announced in a televised address that his government was lifting the martial law declaration.

The opposition parties earlier submitted a separate motion to impeach Mr. Kim, alleging he recommended Mr. Yoon impose martial law. On Wednesday, Mr. Kim offered to resign and apologised for causing disruption and concern to the public. Mr. Kim said “all troops who performed duties related to martial law were acting on my instructions, and all responsibility lies with me,” according to the Defence Ministry.

The impeachment motion on Mr. Yoon was introduced at a parliamentary plenary session early Thursday, meaning it can be put to a vote between Friday and Sunday. By law, the motion will be scrapped if it isn’t voted within 72 hours of its parliamentary introduction. Opposition parties can submit a new impeachment motion if the current one is scrapped or voted down, according to National Assembly officials.

Prospects for Mr. Yoon’s impeachment aren’t clear as Mr. Yoon’s ruling conservative People Power Party decided Thursday to oppose the motion’s passage. Choo Kyung-ho, the floor leader of the PPP, told reporters that his party would hold another meeting to determine how to oppose the motion’s passage. Observers say PPP members could simply boycott a floor vote or cast ballots against the motion.

Impeaching him would require support from two-thirds of the single-chamber National Assembly, or 200 of its 300 members. The opposition parties together have 192 seats and they need additional votes from the PPP. Some experts earlier said the motion will likely be passed through parliament as 18 PPP lawmakers, who belong to an anti-Yoon faction in the party, already voted down Mr. Yoon’s martial law decree together with opposition lawmakers.

But speaking to reporters Thursday, PPP leader Han Dong-hun, head of the anti-Yoon faction, said he would work to ensure that the impeachment motion doesn’t pass though he remains critical of Mr. Yoon’s action, which he described as “unconstitutional.” Han said that there is a need to “prevent damage to citizens and supporters caused by unprepared chaos.”

Experts say rival factions in PPP could unite not to repeat their traumatic experiences following the 2016 impeachment of scandal-ridden conservative President Park Geun-hye, which happened after some lawmakers at her own party voted to impeach her. Mr. Park was eventually removed from office and arrested in 2017, and the liberals easily won the presidency in a by-election as conservatives remained in disarray.

If Mr. Yoon is impeached, he will be deprived of his constitutional powers until the Constitutional Court rules. Prime Minister Han Duck-soo, who holds the No. 2 position in the South Korean government, would take over presidential responsibilities.

The impeachment motion on Mr. Yoon accuses him of attempting a “self-coup” by mobilising the military. It also says Mr. Yoon’s declaration failed to meet the constitutional requirements that such steps should only be considered in severe crisis situations. The motion also argues that his move to declare a suspension of political party activities and deploy troops in an attempt to seal the National Assembly amounted to rebellion.

Mr. Yoon’s martial law declaration, the first of its kind in more than 40 years, harkened back to South Korea’s past military-backed governments when authorities occasionally proclaimed martial law and other decrees that allowed them to station soldiers, tanks and armoured vehicles on streets or at public places such as schools to prevent anti-government demonstrations. Until Tuesday night and Wednesday morning, such scenes of military intervention had not been seen since South Korea achieved a democracy in the late 1980s.

After Mr. Yoon’s declaration, troops carrying full battle gear, including assault rifles, tried to keep protesters away from the National Assembly as military helicopters flew overhead and landed nearby.

It wasn’t clear how the 190 lawmakers were able to enter a parliamentary hall to vote down Mr. Yoon’s martial law decree. Opposition leader Lee Jae-myung and National Assembly Speaker Woo Won Shik were seen climbing over walls. As troops and police officers blocked some from entering, they didn’t aggressively restrain or use force against others.