Key Facts

—The ruling. Justice Alexandre de Moraes barred Senator Flávio Bolsonaro from visiting his jailed father for 90 days.

—The reason. Moraes ruled Flávio used a visit to obtain a letter that was then posted online, sidestepping a social-media ban.

—The candidate. Flávio is the leading opposition pre-candidate for Brazil’s presidential election.

—The timing. The ban runs to about mid-October, past the first-round vote set for October 4.