By BROOK LARMER, MAY 2, 2018

As the rogues’ gallery of fallen world leaders grows, you might be tempted to conclude that ours is the most corrupt era in history. Early last month, the former South Korean president Park Geun-hye was sentenced to 24 years in prison and fined $17 million for bribery, extortion and abuse of power. That same day, the former South African president Jacob Zuma, forced to resign in February by his own party, appeared in court to face charges over a $2.5 billion arms deal. The next day came an even bigger blow: Luiz Inácio Lula da Silva, Brazil’s former president and current front-runner in polls for October’s presidential election, began serving a 12-year jail term on corruption charges — in a federal police building he himself inaugurated more than a decade ago.