SEOUL — South Korea’s Constitutional Court struck down the impeachment of the country’s prime minister Han Duck-soo and restored his powers on Monday, the latest twist in a months-long political saga that started when President Yoon Suk Yeol declared martial law late last year.

The ruling comes as South Korea waits for the same court to decide whether it will impeach Yoon, whose short lived suspension of civilian legal processes briefly banned political activity and sent troops to the heart of the nation’s democracy, plunging the US treaty ally and economic powerhouse into turmoil.

Yoon was later suspended by lawmakers on December 14, after which Han assumed the role of acting president.

But Han lasted less than two weeks in the role, before the main opposition party filed an impeachment motion against him, owing to his refusal to appoint one of the three vacant seats in the Constitutional Court.

In the motion, the Democratic Party called his refusal to appoint justices “an act violating the duty of protecting the Constitution and seriously undermining the rule of law.”

It also held him responsible for helping to plot the martial law declaration and attempting to co-run state affairs with the ruling party before Yoon was suspended, as well as refusing to pass a special investigation bill targeting first lady Kim Keon-hee.

Only one of the eight judges voted to uphold the motion. In its statement the court said there was no evidence Han had sought to neutralize the constitution by failing to appoint judges and so should not be impeached.

Monday’s ruling reinstates Han to the position of acting President while Yoon’s court case continues.

Han, a 75-year-old career politician, told journalists after the ruling that he welcomed the court’s “wise” decision.

The court is yet to rule on whether Yoon should be impeached for his declaration of martial law, which he made in an unannounced television address, accusing the main opposition party of sympathizing with North Korea and of “anti-state activities.”

He cited a motion by the Democratic Party, which has a majority in parliament, to impeach top prosecutors and reject a government budget proposal.

Yet within just six hours, he was forced to back down, after lawmakers forced their way past soldiers into parliament to unanimously strike down the decree.

During his trial at the Constitutional Court last month, Han denied plotting martial law with Yoon. He claimed that he tried “to dissuade” Yoon during the short Cabinet meeting that was held just before Yoon announced the martial law. — CNN