South Korea president to face second martial law impeachment vote

South Korean lawmakers are set to vote Saturday on whether to impeach President Yoon Suk Yeol over his failed martial law bid, in a second parliamentary showdown that appeared on a knife edge.

A week after a first attempt to remove Yoon for the martial law debacle foundered, the National Assembly will vote Saturday around 4:00 pm (0700 GMT) on whether to impeach the president for "insurrectionary acts undermining the constitutional order".

Two hundred votes are needed for the measure to pass, meaning opposition lawmakers must convince eight parliamentarians from Yoon's conservative People Power Party (PPP) to defect.

As of noon Friday, seven ruling party lawmakers had pledged to support impeachment -- leaving the vote up in the air.

Thousands of South Koreans have taken to the streets of Seoul to demand Yoon's resignation and jailing, after his short-lived martial law declaration sent soldiers and helicopters to parliament on December 3-4.

On Friday, the leader of the opposition Democratic Party, Lee Jae-myung, implored ruling PPP lawmakers to side with the protesters and back Yoon's removal from office.

"What the lawmakers must protect is neither Yoon nor the ruling People Power Party but the lives of the people wailing out in the freezing streets," Lee said.

"Please join in supporting the impeachment vote tomorrow. History will remember and record your choice."

Opposition lawmaker Kim Min-seok said Friday he was "99 percent" sure the impeachment motion would pass.

Should it be approved, Yoon will be suspended from office while South Korea's Constitutional Court deliberates.

Prime Minister Han Duck-soo will step in as the interim president during that time.

The court will then have 180 days to rule on Yoon's future. If it backs his removal, Yoon will become the second president in South Korean history to be successfully impeached.

There is also precedent for the court to block impeachment: in 2004, then-president Roh Moo-hyun was removed by parliament for alleged election law violations and incompetence, but the Constitutional Court later reinstated him.

The court also currently only has six judges, meaning their decision would need to be unanimous.

And should the vote fail, Yoon can still face "legal responsibility" for the martial law bid, Kim Hyun-jung, a researcher at the Korea University Institute of Law, told AFP.

"This is clearly an act of insurrection," she said.

"Even if the impeachment motion does not pass, the president's legal responsibilities under the Criminal Code... cannot be avoided."

Yoon has remained unapologetic and defiant as the fallout from his disastrous martial law declaration has deepened and an investigation into his inner circle has widened.

On Friday, prosecutors said they had arrested a military commander who headed the Capital Defence Command. Arrest warrants were also issued by Seoul Central District Court for the national police chief and the head of the city's police, citing "risk of destruction of evidence".

In a televised address, Yoon vowed on Thursday to fight "until the very last minute" and doubled down on unsubstantiated claims the opposition was in league with the country's communist foes.

Yoon's approval rating -- never high -- has plummeted to 11 percent, according to a Gallup Korea poll released Friday.

Protesters calling for his ouster for more than a week run the gamut of South Korean society -- from K-pop fans waving glowsticks to retirees and blue-collar workers.

"Impeachment is a must and we must fight relentlessly," Kim Sung-tae, a 52-year-old worker at a car parts manufacturer, told AFP.

Teacher Kim Hwan-ii agreed.

"I'm so angry that we all have to pay the price for electing this president."