After half a year of political turmoil, uncertainty and division, South Koreans voted Tuesday for a new president to succeed Yoon Suk Yeol, the disgraced former leader who plunged the democratic nation into chaos by declaring martial law in December.

South Korea’s opposition-controlled National Assembly has voted to impeach the country’s acting leader, Han Duck-soo. The assembly approved the impeachment motion in a 192-0 vote on Friday. Governing party lawmakers boycotted the vote. South Korea’s ...