Last week’s election in Argentina produced a result that few predicted. Mauricio Macri, the center–right mayor of Buenos Aires, secured almost as many votes as the favorite, Daniel Scioli, the former powerboat racer and governor of the province of Buenos Aires. Scioli, the candidate for the incumbent Front for Victory (FPV) coalition, who the outgoing president, Cristina Fernandez de Kirchner, had reluctantly endorsed, won 36.8 percent of the vote; Macri’s coalition, called “Let’s Change,†won 34.3 percent. To avoid a second round vote, Argentina’s constitution requires that one party receive more than 45 percent of the vote (or at least...