What is martial law? What happened in South Korea and what it means

With debate surrounding a martial law declaration in South Korea this week, many are wondering what does such a declaration actually mean and what are the rules around it?

Questions first surfaced when South Korean President Yoon Suk Yeol declared martial law late Tuesday. Hours later, parliament voted to lift the declaration, with National Assembly Speaker Woo Won Shik declaring that the martial law was “invalid” and that lawmakers “will protect democracy with the people.”

Here's an explainer on martial law and a look at what unfolded so far this week:

What is martial law?

According to the U.S. Department of Justice, "martial law involves the temporary substitution of military authority for civilian rule and is usually invoked in time of war, rebellion, or natural disaster."

"When martial law is in effect, the military commander of an area or country has unlimited authority to make and enforce laws," the department states.

What is required for martial law to be declared?

Under South Korea's constitution, the president may proclaim martial law when “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," according to the New York Times.

Why was martial law declared in South Korea?

In his declaration, Yoon vowed to eliminate “anti-state” forces as he struggles against an opposition that controls the country’s parliament and that he accuses of sympathizing with communist North Korea.

Yoon said during a televised speech that martial law would help “rebuild and protect” the country from “falling into the depths of national ruin.” He said he would “eradicate pro-North Korean forces and protect the constitutional democratic order.”

“I will eliminate anti-state forces as quickly as possible and normalize the country,” he said, while asking the people to believe in him and tolerate “some inconveniences.”

Yoon — whose approval rating has dipped in recent months — has struggled to push his agenda against an opposition-controlled parliament since taking office in 2022.

During his televised announcement, Yoon also described the opposition as “shameless pro-North Korean anti-state forces who are plundering the freedom and happiness of our citizens,” but he did not elaborate.

What was the response to the declaration?

Yoon’s surprising move harkened back to an era of authoritarian leaders that the country has not seen since the 1980s, and it was immediately denounced by the opposition and the leader of his own conservative party.

It marked the first declaration of martial law since the country’s democratization in 1987. The country’s last previous martial law was in October 1979, following the assassination of former military dictator Park Chung-hee.

The leader of Yoon’s conservative People Power Party, Han Dong-hoon, called the decision “wrong” and vowed to “stop it with the people.” Lee, who narrowly lost to Yoon in the 2022 presidential election, called Yoon’s announcement “illegal and unconstitutional.”

Soon after the declaration, parliament speaker Woo called on his YouTube channel for all lawmakers to gather at the National Assembly. All 190 lawmakers who participated in a subsequent vote supported the lifting of martial law.

Lee Jae-myung, leader of the liberal Democratic Party, which holds the majority in the 300-seat parliament, said the party’s lawmakers would remain in the Assembly’s main hall until Yoon formally lifts his order.

“Democratic Party lawmakers, including me and many others, will protect our country’s democracy and future and public safety, lives and properties, with our own lives,” Lee told a televised news conference.

What does it take for martial law to be lifted?

Under South Korean law, martial law can be lifted with a majority vote in the parliament.

Has martial law ever been declared in the U.S.?

According to the Justice Department, martial law has been declared nine times since World War II, five of which were "designed to counter resistance to Federal desegregation decrees in the South."