Lee Jae-myung will be one of the most powerful presidents in decades in South Korea, but he is taking over during a perilous political atmosphere.

© Jun Michael Park for The New York Times

After months of political turmoil in South Korea, Lee Jae-myung has won the presidential election by a wide margin. Mr. Lee’s campaign has ridden a wave of anger against former President Yoon Suk Yeol after he tried to impose martial law in December.

The new president will be tasked with pulling the nation out of political turmoil and face a polarized country and world.

© Jun Michael Park for The New York Times