Keep your friends close, and your vice president closer

In theory, the vice president is little more than a symbolic figure in Brazilian politics. A president’s running mate is often used as a way of giving prestige to allied parties and the office itself is largely ignored by the public, having virtually no institutional responsibilities other than being an emergency “just-in-case” option.

In reality, however, that is not the case.

Of Brazil’s 38 presidents, eight of them took the job after being elected vice president and seeing the top job vacated for a number of reasons, be it death, resignation, or impeachment. Since the country’s return to democracy in 1985, three VPs have already taken office as president: José Sarney (in 1985, after the death of Tancredo Neves prior to his inauguration), Itamar Franco (in 1992, after Fernando Collor’s impeachment), and Michel Temer (in 2016, after Dilma Rousseff was removed from office).

And today, President Jair Bolsonaro seems to believe that his own vice, Hamilton Mourão, wants to be the ninth VP to be promoted to the highest office in the land — a suspicion that is driving a deep wedge between the two men.

Last week, Mr. Bolsonaro...