Late last year, Venezuela’s democratic opposition set out to choose, jointly, someone who could challenge Nicolás Maduro, the country’s autocratic president, in an election that was sure to be violent and unfair. Hundreds of thousands of participants from different political parties voted in a primary held across Venezuela and in exile communities abroad. Although they risked harassment and arrest, people donated space in private homes and offices to make the vote possible. Others stood in line for hours, in parks and plazas, to choose the victor, María Corina Machado. Machado’s…