Seoul –

South Korea's Constitutional Court reinstated Prime Minister Han Duck-soo to the post of acting president on Monday, striking down his impeachment as he pledged to focus on steering Asia's fourth-biggest economy through a U.S. "trade war."

The ruling, which comes amid months of political turmoil in the country, returns Han to power immediately. He took over as acting leader from President Yoon Suk Yeol, who was himself impeached over his brief imposition of martial law in December.

"I believe the people are making it very clear, in one voice, that the extreme confrontation in politics must stop," said Han, who thanked the court for its "wise decision" and the Cabinet for their hard work while he was suspended.

"As acting president, I will do my best to maintain stable state administration, and devote all wisdom and capabilities to safeguard national interests in the trade war," he said in televised comments.

South Korea, one of the world's top exporters, has been bracing for the potential impact of a range of threatened tariffs under U.S. President Donald Trump.

South Korea has already seen U.S. tariffs on steel and aluminum and has been seeking an exemption from reciprocal U.S tariffs due to come in next month. Earlier this month, Trump singled out South Korea for applying high tariffs on U.S. exports.

Yoon's martial law declaration plunged the key U.S. military ally into its greatest political crisis in decades, and sparked a leadership vacuum amid spiraling impeachments, resignations, and criminal indictments for a range of top officials.

Han lasted less than two weeks as acting president following Yoon's impeachment and was himself impeached and suspended on Dec. 27 after clashing with the opposition-led parliament by refusing to appoint three more justices to the Constitutional Court.

The justices on the court ruled on Monday 7-to-1 to strike down Han's impeachment.

Five of the eight justices said the impeachment motion was valid, but ruled that there were not enough grounds to impeach Han as he did not violate the constitution or the law, according to a court statement.

Two justices ruled that the impeachment motion against Han was invalid from the start as two-thirds of lawmakers in parliament did not pass it.

One justice voted to impeach Han.

"Civil war"

Han, 75, had served in leadership positions for more than three decades under five presidents, both conservative and liberal.

In a country sharply divided by partisan rhetoric, Han had been seen as a rare example of an official whose varied career transcended party lines.

Still, the opposition-led parliament accused him of not doing enough to thwart Yoon's decision to declare martial law, an accusation he denied.

Lee Jae-myung, head of the opposition Democratic Party, said Han's ruling must be accepted but urged the Constitutional Court to swiftly make a decision on Yoon's impeachment.

The court is expected to rule within days, though its deliberations have dragged out longer than expected. Yoon also faces a separate criminal trial on charges of leading an insurrection by declaring martial law.

If Yoon is removed, a new presidential election will be held within 60 days.

"The court's continued delay in ruling is fueling concern and conflict ... We can now anticipate the situation going beyond a psychological civil war to become an actual physical civil war," said Lee, who is leading in opinion polls to win an election if Yoon is removed.

South Korea has seen huge, mostly peaceful, rallies — both in support of Yoon and calling for his removal — in recent months.

Finance Minister Choi Sang-mok had assumed the position of acting president while the cases of Yoon and Han were considered by the Constitutional Court.

Yoon's unexpected imposition of martial law on Dec. 3 and the ensuing political upheaval sent shock waves through South Korea, and raised concern among allies such as the United States under former President Joe Biden, who had seen the South Korean president as a key partner in efforts to counter China and North Korea.

The martial law in the end only lasted about six hours after lawmakers defied a security cordon around parliament and voted to reject the declaration.