BRAZILIA - Brazil is holding its elections on Sunday, and fears are rising as to whether Jair Bolsonaro, its anti-democratic president, will accept a defeat.

On Wednesday, Bolsonaro’s political party released a document that claimed, without evidence, that government employees and contractors had “absolute power to manipulate election results without leaving a trace.” The electoral authority immediately rebuked the claims, calling them “false and dishonest, with no backing in reality.”

But Bolsonaro may well have to override voters and strong-arm a result to stay in power. In polls, he has long trailed Luiz Inácio Lula da Silva, the former president. If da Silva surges to power, it would be a once unthinkable comeback for the zealous leftist, who was in prison on corruption charges just three years ago.

For months, Brazilian officials and foreign diplomats have feared that Bolsonaro was setting the stage to dispute an election loss.

If no candidate receives 50 percent of the vote, the top two finishers will compete in a runoff on October 30. But it looks increasingly likely that da Silva could win outright.