The pact is a blow to center-left presidential candidate Ciro Gomes, who is running third in early polling and sought the backing of the PSB to boost his chances of making the run-off between the two most voted candidates on Oct. 7.
Brazil's former President Luiz Inacio Lula da Silva's Workers Party (PT) has reached a neutrality pact with the Brazilian Socialist Party (PSB) that will end their rivalries in several states in the October general elections.
The Workers Party announced the move in a statement on Wednesday, while the PSB must still ratify at its convention on Sunday a commitment not to back any presidential candidate since it is not fielding its own.
It also confirms that Brazil's left will enter the election divided, which could help the business-friendly center-right candidate Geraldo Alckmin and far-right hopeful Jair Bolsonaro, who is currently the front-runner riding on voter anger with political corruption and rising crime.
In Brazil's most uncertain race in decades, the Workers Party plans to nominate Lula at its convention on Saturday, even though he cannot campaign and will almost certainly be barred from running due to a contested corruption conviction. Lula, who is still Brazil's most influential politician, is expected to name a stand-in at the last minute in mid-September.
The Workers Party will withdraw Marilia Arraes, its candidate for governor who was threatening the re-election of Paulo Camara in the PSB's most important state, Pernambuco.
In return, the PSB will not run against the Workers Party governor of Minas Gerais, Fernando Pimentel, party officials told Reuters.