Calls are growing for South Korean President Yoon Suk-yeol to resign, two days after he declared martial law only to be forced by the country’s parliament to reverse that decision.

At the same time, Yoon is facing a motion for impeachment from opposition MPs in parliament. The impeachment vote is expected on Friday or Saturday.

We explain how Yoon could be charged and who could take his place if he resigns – or is forced out.

Why did Yoon declare martial law?

In an unscheduled televised address late Tuesday, Yoon declared martial law in South Korea.

He accused the main opposition party, the Democratic Party, of sympathizing with North Korea and engaging in subversive activities. He expressed the need to “protect the country from North Korean communists and eliminate anti-state elements,” but provided no evidence to support his accusations against the opposition.

Yoon’s defense minister, who has since resigned, confirmed that troops were then ordered to blockade the National Assembly building around midnight. However, South Korean parliamentarians entered the parliament building past the security forces. The 190 MPs present – out of a total of 300 – voted unanimously to lift martial law. This caused Yoon to back down.

The next day, six opposition parties, including the Democratic Party, filed an impeachment motion against Yoon.

How do impeachment proceedings work in South Korea?

According to South Korea’s constitution, two-thirds of the members of the National Assembly must vote to impeach a sitting president.

Six of nine Constitutional Court judges must vote to uphold the impeachment and remove Yoon.

Even if the court votes against the impeachment, the opposition parties can repeat the process.

Will Yoon Suk-yeol be charged?

The opposition parties, including the Democratic Party, have a combined total of 192 seats. They would need the support of at least eight members of Yoon’s conservative People Power Party to pass the impeachment motion.

If the motion is approved, Yoon will be temporarily stripped of his authority as president until the Constitutional Court decides his fate.

Yonhap News Agency reported that the vote on the motion is expected to take place on December 6 or 7.

The agency also reported Wednesday that senior presidential aides and senior secretaries submitted mass resignations following political turmoil in South Korea. This also includes Defense Minister Kim Yong-hyun.

Al Jazeera’s Eunice Kim reported from Seoul on Tuesday that calls for Yoon’s removal were not new, but sentiment had grown following recent political turmoil.

A survey by South Korean pollster Realmeter showed on Thursday that 73.6 percent of respondents supported Yoon’s removal from office.

Yoon appears to have lost some support within his own party, whose leaders have said they do not support his attempt to impose martial law. However, Choo Kyung-ho, parliamentarian and leader of the People Power Party, said at a livestreamed party meeting on Thursday that “all 108 MPs of the People Power Party will remain united and oppose the impeachment of the president.”

Who would replace Yoon if he was removed?

If Yoon’s presidential powers are suspended due to impeachment, Prime Minister Han Duck-soo will take Yoon’s place.

However, South Korea would have to hold a presidential election within 60 days if Yoon is removed.

Who is Prime Minister Han Duck-soo?

Yoon appointed the 75-year-old Han as prime minister in 2022 after Yoon won the presidential election that same year.

Han began working as a civil servant in the early 1970s. Han completed his master’s degree in economics from Harvard University in 1983 and his doctorate in economics from Harvard University in 1984.

From 2007 to 2008, Han served as prime minister under President Roh Moo-hyun of the liberal Uri Party. Between 2009 and 2012 he was South Korea’s ambassador to the United States.

According to local reports, Yoon did not keep Han updated on his martial law plans, but instead communicated directly with Defense Minister Kim.

If elections are held, Democratic Party leader Lee Jae-myung is the favorite to become South Korea’s next president.

Who is the main opposition leader Lee Jae-myung?

Lee, 60, narrowly lost the 2022 presidential election to Yoon, who won about 48.6 percent of the vote to Lee’s 47.8 percent. Lee is leading the call for Yoon to resign.

According to local media reports, Lee was born into a working-class family and worked in sweatshops during his childhood. He grew up to be a human rights and labor law lawyer.

From 2010 to 2018, Lee served as mayor of Seongnam, a city in South Korea’s most populous province, Gyeonggi. In 2018, he became governor of Gyeonggi and remained in office until 2021. In 2022 he became a member of the National Assembly.

In January this year, he survived a knife attack during a visit to the southeastern port city of Busan. A man stabbed him in the neck.

In November, Lee was convicted of violating election law for lying about a bribery scandal about development projects during the 2022 presidential campaign when he was mayor of Seongnam. He was given a one-year suspended prison sentence.

Lee said he would appeal that ruling. However, if he loses this appeal, he will lose his position as a legislator and will not be able to run in the next presidential election.