What to know about South Korean President Yoon Suk Yeol

Zoom in: Yoon, 63, promised a harder line on North Korea when he entered office as a political newcomer. He became the 20th president of the Republic of Korea in May 2022.

• Before that, he worked as a prosecutor for 26 years in jurisdictions including Daegu, Seoul and Suwon.
• He became prosecutor general of the Supreme Prosecutors' Office in 2019, responsible for overseeing the office's overall work, prosecution affairs and public officials of the prosecution service.
• He earned bachelor's and master's degrees in law from Seoul National University.

Between the lines: South Korean presidents serve a single five-year term and cannot run for re-election.

• Via lawsuits, state regulators and criminal investigations, Yoon has restricted speech that he considers misinformation, an effort largely aimed at news organizations, per the New York Times.

Zoom out: South Korea's constitution declares that the president can proclaim martial law "when it is required to cope with a military necessity or to maintain the public safety and order by mobilization of the military forces in time of war, armed conflict or similar national emergency."

• There are two types of martial law: precautionary and extraordinary, which allows for special measures with "warrants, freedom of speech, the press, assembly and association or the powers of the Executive and the Judiciary."

State of play: The leader of Yoon's own conservative party, Han Dong-hoon, denounced his decision to declare martial law, per the AP. So did his opponents, including Lee Jae-myung, who he narrowly defeated in the 2022 election.

• Yoon accused the opposition of anti-state rebellion in his announcement.

His approval rating has decreased in recent months, per the AP. Disapprovers of Yoon cited rising consumer prices and a lack of communication with the public, per Gallup Korea, the Korea Herald reported.

• He has struggled to implement his agenda with the opposition-controlled parliament.

Flashback: Earlier this year, Yoon's wife was embroiled in controversies including allegedly accepting a luxury Dior handbag and stock manipulation, per the BBC, causing rifts within his party.

• At the time, Yoon said she should have conducted herself better but that the claims had been "exaggerated."

• Also this year, Yoon vetoed an investigation into the death of a marine in 2023. The death became an impeachment threat for the leader, per the NYT.

Catch up quick: U.S. lawmakers have praised Yoon's efforts to improve South Korea's relationship with Japan, which is a fellow U.S. ally and South Korea's previous colonial ruler.

• Relations between Seoul and Tokyo have improved since Yoon's term, per the European Council on Foreign Relations.

In November, Yoon told Chinese President Xi Jinping during the Asia-Pacific Economic Cooperation forum in Lima, Peru, that their countries should cooperate for peace in response to North Korean and Russian military cooperation, per Reuters.

• Xi told Yoon that irrespective of changes in the region, the countries should tap into advantages like integrated economies and cultural similarities to deepen cooperation.
• Months prior, South Korea became the first Asian country to sign a North Atlantic Treaty Organization agreement on mutual recognition for military airworthiness certification.

Yoon has allied himself with anti-feminist sentiment, per the New York Times, by accusing the ministry of gender equality of treating men like "potential sex criminals," during a 2022 political movement.

Go deeper: South Korean president declares martial law in shock move

Editor's note: This story has been updated with additional context.