After 40 years, the Vatican canonized El Salvador’s Archbishop Óscar Arnulfo Romero as a saint, and the Economist describes this as a “controversial” choice: “Often seen as ideologically left wing, he was above all a martyr for his faith and his church.” In the 1970s, El Salvador’s long-ruling coffee oligarchy and army were confronted by left-wing trade unions and peasant groups, with aid from...