By Joyce Lee
SEOUL (Reuters) -South Korea's leadership crisis will play out in the Constitutional Court, which will decide the fates of President Yoon Suk Yeol and Prime Minister Han Duck-soo, both impeached and suspended from power over a short-lived martial law.
Han, who was impeached on Friday, had taken over as acting president from Yoon, impeached on Dec. 14. Finance Minister Choi Sang-mok has become acting president.
Also on Friday, the court held its first hearing in a case to decide whether to reinstate Yoon or remove him permanently from power.
WHAT NEXT?
After being impeached on Dec. 14, Yoon's presidential powers were suspended but he remains in office, retaining his immunity from most charges except insurrection or treason.
The Constitutional Court must decide within 180 days whether to remove him from office or reject the impeachment and restore his powers. If it removes Yoon or he resigns, a presidential election must be held within 60 days.
Opposition Democratic Party lawmaker Jung Chung-rae, the head of parliament's Legislation and Judiciary Committee, is leading the case for removing Yoon.
Yoon's legal counsel include former Constitutional Court spokesperson Bae Bo-yoon and former prosecutor Yoon Kab-keun, who appeared at Friday's hearing.
The court is also expected to hold a trial on whether to remove Han from office or restore him to his role.
HURDLES TO A COURT RULING?
South Korea's constitution requires six justices to agree on the ouster of an impeached president. The nine-member court has one remaining vacancy, after Choi appointed two new justices on Tuesday.
Choi said on Tuesday that he will fill the last remaining vacancy as well if ruling and opposition parties can agree on the nomination.
There is precedent for an acting president to appoint a Constitutional Court justice, when former President Park Geun-hye was impeached in late 2016.
WHAT HAPPENS IN COURT?
In South Korea's only previous presidential removal by impeachment, the court took three months to oust Park in 2017.
This time, the terms of two court justices expire in April, and legal experts predict it may seek to rule before that to minimise uncertainty.
On Friday, Justice Cheong Hyung-sik of the Constitutional Court said it would move swiftly in the case, considering its gravity.
In the past, academics say, the justices have not voted predictably by political leaning but have decided case by case, going by their interpretation of the constitution.
Attempts by conservatives to rally popular support for Yoon are not expected to affect the court's ruling, as Park was removed from office despite continued rallies to keep her in power, warring with candlelight protests seeking her removal.
In the case of Park, who like Yoon was from a centre-right party, the court voted unanimously to remove her, including some justices viewed as conservative and two Park appointees.
Yoon also faces criminal investigations related to the martial law decision.
If charged, he could ask the Constitutional Court to suspend the 180-day clock on the impeachment ruling. The court denied a similar request by Park.
In 2004, then-President Roh Moo-hyun, from a centre-left party, was impeached for falling short of the political neutrality required of a high public official, but finished his five-year term after the court rejected the motion within two months.