Lee Jae-myung, a progressive who leads the Democratic Party of Korea, is the new president of South Korea.

His victory Tuesday in a ballot to replace Yoon Suk Yeol, impeached after trying to launch a coup last year, caps an extraordinary life that took him from slums outside Seoul to his nation¡¯s highest office.

He will need all that experience to address the daunting array of challenges ¡ª most immediately, uniting a bitterly divided public ¡ª that he inherits. Lee moderated his positions during the campaign in an attempt to make that job easier. That was enough to win a mandate in this week¡¯s ballot but far more will be required if South Korea is to navigate the difficult political and economic shoals that it faces.