RIO DE JANEIRO, BRAZIL - Fear palpitates in a crowded square. On the stage, the Colombian candidate Gustavo Petro, wearing a bulletproof vest, surrounded by an army of bodyguards who exchange nervous glances, can barely peek his head through three armored shields.
The specter of assassination is haunting the campaign for the May 29 presidential elections, in which, for the first time, the left has a chance of coming to power with the help of . . .