A conviction would also be a clear and strong repudiation of Mr. Bolsonaro’s tactics to undermine the vote, and a warning to any political allies who might be considering a similar strategy.

Mr. Bolsonaro’s rhetoric resembled that of former President Donald J. Trump, a political ally. But the results for the two men could prove very different. Just six months after leaving office, Mr. Bolsonaro is facing charges that could end his political career. At the same time, while Mr. Trump faces investigations into his efforts to question the 2020 U.S. election, he is still the leading contender to become the Republican Party’s nominee in next year’s presidential vote.

The Background: Bolsonaro has long attacked Brazil’s elections.

Mr. Bolsonaro spent years criticizing Brazil’s voting systems, claiming that they were vulnerable to fraud and that his rivals were bent on rigging them, despite a lack of evidence. His commentary led millions of his followers to lose faith in the election systems and believe that Mr. Lula stole the 2022 election.

Despite Mr. Bolsonaro’s assertions, numerous reviews of the election results found no credible evidence of fraud.

One week after Mr. Lula was inaugurated in January, many of Mr. Bolsonaro’s followers invaded and ransacked Brazil’s halls of power in a bid to get the military to take control of the government.