A South Korean court’s conviction of Seoul’s mayor for illegal polling payments threatens to put an end to his presidential ambitions just weeks after he won a historic fifth term. Oh Se-hoon, the 65-year-old conservative who has led South Korea’s capital on and off for nearly two decades, was fined 10 million won (US$6,800) on Wednesday for violating the Political Funds Act ahead of the mayoral by-election in 2021. Under South Korean law, any elected official fined more than 1 million won for...