The re-election campaign for Brazilian President Luiz Inácio Lula da Silva has filed a high-stakes legal challenge with the Superior Electoral Court (TSE), seeking to declare rival presidential candidate Flávio Bolsonaro ineligible for office. The move, coming in the final weeks of what polls indicate is a tight race, ratchets up political uncertainty by targeting the main opposition standard-bearer and eldest son of former President Jair Bolsonaro.