Why did South Korea declare martial law, what’s next for President Yoon?

In a surprise late-night address on Tuesday, South Korea’s President Yoon Suk-yeol announced the imposition of martial law, citing a motion by the main opposition Democratic Party, which holds a parliamentary majority, to impeach top prosecutors and reject a government budget proposal.

But less than two hours after the martial law declaration, lawmakers forced their way past soldiers to vote to strike down his decree. Yoon accepted the reversal six hours later.

Here is what we know about the political impasse:

What happened in South Korea on Tuesday?

In an unscheduled televised address at about 11pm (14:00 GMT), Yoon declared martial law, accusing the Democratic Party of sympathising with North Korea and engaging in antistate activities.

His decree briefly handed control to the military, deploying troops and police to the National Assembly building, where helicopters were spotted landing on the roof.

South Korean politicians swiftly condemned Yoon’s declaration as illegal and unconstitutional. Opposition leader Lee Jae-myung urged Democratic Party MPs to gather and vote to reject the declaration.

Thousands took to the streets, but tensions did not give way to violence despite the military presence. Lawmakers managed to bypass the barricades, and when they arrived at the chamber, they unanimously voted to block the decree during an emergency late-night session, with 190 of South Korea’s 300 National Assembly members present.

At about 4:30am (19:30 GMT), Yoon said he would reverse his decision. He confirmed in a statement that the troops sent to carry out the order would be withdrawn, but he repeated his original justification for the decree.

Protesters clash with police officers during a demonstration calling for the resignation and impeachment of President Yoon outside the National Assembly [Han Myung-Gu/EPA]

What is martial law?

Martial law is a temporary form of governance by military authorities during emergencies.

South Korea’s constitution states that the president can declare martial law when necessary to address a military threat or maintain public safety and order by deploying military forces.

According to the Center for Strategies and International Studies (CSIS), Yoon invoked emergency martial law.

By declaring emergency martial law, Yoon has the authority to “[limit] freedom of speech, publication, assembly, and association,” according to the CSIS.

In this instance, the order placed all media outlets under martial law control and instructed all medical personnel, including striking doctors, to resume work within 48 hours.

Thousands of doctors have been on strike in South Korea since early February over a proposal to increase medical school admissions, forcing hospitals to cancel treatments and surgeries. The government says the reforms are needed to alleviate staff shortages and manage the country’s transition to an ageing society.

Youngshik Bong, a visiting professor at Yonsei University and adviser for South Korea’s Ministry of Unification, said declarations of martial law under Article 77 of the constitution must be reserved for the most serious situations, such as actual war.

“But we [didn’t] have this situation,” Youngshik told Al Jazeera. “This is not a game the president can win.”

A South Korean tourist watches a Japanese TV broadcast on a phone showing President Yoon declaring martial law in a televised emergency address [Jeon Heon-Kyun/EPA]

Why did Yoon declare martial law?

The declaration of martial law comes after months of declining public support, with a survey last week revealing Yoon’s approval rating had fallen to just 25 percent.

In his declaration, he focused on his domestic political opponents and did not cite any specific threat from North Korea. He complained of 22 impeachment motions filed against administration officials since he took office in May 2022.

Since taking office in 2022, Yoon has faced challenges in advancing his agenda in an opposition-controlled parliament. His party is now locked in a deadlock with the liberal opposition over next year’s budget.

Yoon has also rejected calls for independent investigations into scandals involving his wife and senior officials, generating criticism from his political opponents.

South Korea’s National Assembly after President Yoon announced his intention to lift the emergency martial law [Han Myung-Gu/EPA]

Could Yoon face impeachment now?

A group of lawmakers from opposition parties said they plan to introduce a bill to impeach Yoon on Wednesday, with the vote expected within 72 hours.

The National Assembly can impeach the president if more than two-thirds of lawmakers vote for it.

The Democratic Party, along with some smaller parties, holds 192 seats, just eight short of the 200 needed to impeach the president.

Some members of Yoon’s People Power Party also strongly opposed his martial law declaration. It remains unclear how many, if any, will join the opposition if a motion is put to a vote.

Democratic Party leader Lee Jae-myung (C) announces his stance at the National Assembly in Seoul [Yonhap via EPA]

If the impeachment is voted on and approved, a trial will be held before the Constitutional Court, a nine-member body that oversees South Korea’s government branches. If six of the court’s members vote to uphold the impeachment, the president will be removed from office.

Earlier this morning, Yoon’s staff offered to resign en masse, although the president has not yet made any public appearance.

The Korean Confederation of Trade Unions, one of the country’s largest labour organisations, also called for a strike until Yoon’s resignation.

“Normally, they don’t actually participate in politics,” Alex Taek-Gwang Lee, a professor of cultural studies at Kyung Hee University in Seoul, told Al Jazeera. “This will accelerate the impeachment movement. And then I think Mr Yoon will be impeached soon.”

Yoon was inaugurated as president of South Korea on May 10, 2022.

What happens if Yoon leaves office?

The prime minister will serve as the acting leader. A new election must be held within 60 days.

In the next hours, more protests are expected.

What have been the reactions?

Inside the country, protests erupted as South Koreans also began stockpiling supplies. Local media reports indicate that the price of canned goods surged by 300 percent and instant noodles by 250 percent between 11pm (14:00 GMT) and midnight (15:00 GMT). Sales of water, instant rice and batteries also saw a significant increase, according to a report by the Reuters news agency.

Internationally, the White House said it was “relieved” by Yoon’s decision to reverse martial law.

Earlier, the United Kingdom and Germany said they were closely following the events. Meanwhile, Russia said it was concerned about the crisis in South Korea. China urged its citizens in South Korea to exercise caution.