South Korean politics is in turmoil, with the impeachment of South Korea's acting president, Prime Minister Han Duck-soo, coming less than two weeks after the opposition-controlled parliament impeached President Yoon Suk Yeol.
The successive impeachments are unprecedented, and mean the top two officials in Asia's fourth-largest economy are currently suspended from their duties.
The deputy prime minister and finance minister, Choi Sang-mok, is now South Korea's new interim leader.
Since taking power on Friday evening, Mr Choi has ordered the military to boost its readiness to thwart potential North Korean aggression, and has moved to reassure key partners like the United States and Japan that South Korea's security and foreign policies remain unchanged.
However, some observers believe the country's adversaries will be looking to take advantage of the ongoing instability, and Mr Choi is less suited to the presidency than the man he replaced.
Here's a look back at the latest developments in the political tumult, as well as how the country's foreign standing will be affected — and what's likely to happen next.
Why was the acting president impeached?
South Korea's latest bout of instability began earlier this month with Mr Yoon's short-lived declaration of martial law on December 3.
The unexpected move — which saw hundreds of troops pour into Seoul's streets, hearkening back to the days of military rule in the 60s and 70s — came as a shock to the public and politicians on both sides of the aisle, as well as causing alarm to the US and other allies.
The declaration — purportedly intended to protect the government from "anti-state forces" — was rescinded just six hours later, in the early hours of December 4, after South Korea's parliament voted unanimously to overturn it, and civilians and politicians took to the streets in protest.
Mr Han, the number two official in the country, became the acting president on December 14, after Mr Yoon's impeachment.
Mr Han, a career public servant and economist, spent the next two weeks trying to reassure Korea's major diplomatic partners and stabilise the markets. But he was also embroiled in political strife with the liberal opposition Democratic Party (DP), which holds a majority in the National Assembly.
A major trigger for Mr Han's impeachment was his refusal to accept a DP demand that he immediately appoint justices to three vacant seats on the country's Constitutional Court, to enhance fairness and public confidence in its upcoming ruling on Mr Yoon's impeachment.
Restoring the court's full nine-member panel is crucial for the opposition because a court ruling to uphold Mr Yoon's removal from office needs backing from at least six justices, meaning a full bench would increase the prospect of Mr Yoon's ouster.
However, Mr Han said he wouldn't appoint the justices without bipartisan consent — a move critics suspected meant he was siding with Mr Yoon's loyalists in the governing People Power Party, or PPP, who want to see Mr Yoon regain power.
Choi Jin, director of the Seoul-based Institute of Presidential Leadership think tank, says Mr Han lacked a legitimate reason to go against the appointment of the court justices.
However, he also believes the DP shouldn't have pursued the acting president's impeachment so hurriedly — and the resulting instability and loss of international standing is far worse for the country than the fallout from the first impeachment.
"Negative effects on economy, culture and all other sectors will likely come quietly and extensively," he says.
Choi Sang-mok himself had asked the opposition on Friday to withdraw its plan to impeach Mr Han, saying it would do serious damage to the economy.
There is also the risk that he may face removal, too, if he clashes with the parliament.
"The government must do its best to ensure that the people do not become anxious," Mr Choi said in a statement issued by his office after he took power.
Will there be further diplomatic fallout?
Mr Han's impeachment comes just as South Korea has been telling the world things have returned to normal in the aftermath of the martial law incident, which caused worries with neighbours, halted high-level diplomacy and shook financial markets.
Mr Yoon's martial law decision baffled policymakers in the US, Japan and Europe, as he has been their key diplomatic partner in dealing with shared challenges including China's assertiveness, North Korean nuclear threats and vulnerabilities in global supply chains.
"South Korea is now in a far more serious crisis of leadership and governance. The DP's political gambit is actually putting the country's economy and national security at grave risk," says Duyeon Kim, a senior analyst at the Center for a New American Security in Washington.
"Han had the experience and credentials to deal with both security and financial crises if they arise during South Korea's political uncertainty.
[His] impeachment now creates an opportunity for external threats, while causing Korea's foreign partners to alienate it from the global community."
Choi Jin, of Seoul's Institute of Presidential Leadership, also doubts Choi Sang-mok will be able to smoothly engage with diplomacy with world leaders.
"We'll suffer a disgrace internationally and our international credibility will plunge," he says.
What's going to happen next?
The governing PPP argues Mr Han's impeachment was invalid because it passed with a simple majority in the 300-member National Assembly, not the two-thirds majority that was required to impeach Mr Yoon.
There are no specific laws on the impeachment of an acting president, and the PPP filed a petition with the Constitutional Court to review the vote.
It's not clear when the court will rule on that request. The Constitutional Court has up to 180 days to determine whether to uphold the impeachment of both Mr Yoon and Mr Han, though it is expected to issue decisions earlier rather than later.
The court had its first pre-trial hearing on Mr Yoon's case on Friday. If he is successfully thrown out of office, a national election to find his successor must take place within 60 days.
Mr Yoon and others face separate probes by investigative agencies on allegations that they committed rebellion, abuse of power and other crimes in connection with the martial law decree.
According to surveys, DP leader Lee Jae-myung is a clear favourite to win a possible presidential by-election in the event of Mr Yoon's ouster.
But Mr Lee has his own legal issues, and could possibly be prohibited from running for president if the Appellate and Supreme courts uphold a previous lower court conviction for violating election laws in November.
If he becomes president, his trials would stop because South Korean law gives a sitting president immunity from most criminal prosecution.
ABC/AP/Reuters
