During the 2018 campaign trail, one gesture symbolized the Jair Bolsonaro campaign more than any other: at every rally, on every social media post, in every photo op with supporters, he could be seen with an open-mouthed grin and his trademark finger guns — less of a branding exercise, and more a campaign promise. For decades, Mr. Bolsonaro has been a vocal supporter of scrapping gun control regulations, asserting that Brazilians must take matters of justice into their own hands. In a 2017 interview, he said “violence must be fought with violence,” while in an April cabinet meeting,...
