After the first round of the Brazilian presidential election three weeks ago, the leftist incumbent Luiz Inácio Lula da Silva reportedly told allies he could not understand how he finished second after a government he considered the best of his three terms.

A mood of dismay swept Brazil’s left, and because 9 million voters for the other candidates, all of them on the right, were expected to mostly transfer to senator Flávio Bolsonaro, analysts widely saw the far-right senator’s victory as certain.

Then, on the night after the election, students from the Fluminense Federal University took to the streets of Niterói, a city of 480,000 across Guanabara Bay from Rio de Janeiro, to protest against the return to power of a member of the Bolsonaro family, whose patriarch, former president Jair Bolsonaro, Flávio’s father, is under house arrest for attempting a coup.

Two days later, another student protest took over downtown Rio and, in the days that followed, similar ones spread across the country in organic…