After nearly 10 months in exile, Ms. Machado, a Nobel laureate, came back to challenge leaders who have sidelined her and press for new elections.

President Luiz Inácio Lula da Silva triumphed over Flávio Bolsonaro, the eldest son of the right-wing leader he defeated four years ago.

Marci Webber was institutionalized after being convicted by reason of insanity for killing her 4-year-old daughter. For years she has said she is cured and should be freed.