As the political stars appear to be aligning in support of Gustavo Rivera’s bid to topple incumbent Pedro Espada, Jr. in the 33rd Senate District, fellow Espada challengers Daniel Padernacht and Fernando Tirado refused to go along with the program.

“Unless something dramatically changes by midnight, I’m staying in the race,” Padernacht said.

Candidates have until midnight tonight to drop out of the race without their names appearing on the ballot. After that, if the candidates’ petition signatures hold up – they need the signatures of at least 1,000 unique registered Democratic voters – then their names will be on the ballot.

Common political handicapping says more challengers will favor Espada in the primary. And Rivera is gaining momentum as the most politically and institutionally supported challenger.

He compiled the most signatures of any challenger – 6,200, he says. He has the most political endorsements, including Councilman Oliver Koppell who announced his support earlier today in front the Amalgamated Houses. And he recently received backing from deep-pocketed, anti-Espada Democrat Bill Samuel’s New Roosevelt Initiative as well the Working Families Party.

Padernacht said he’s received numerous calls since Friday asking him to step down and let Rivera take on Espada one-on-one for the Democratic ticket.

Specifically, Padernacht says he’s received pressure from SEIU 1199 (the healthcare workers union) and the office of Public Advocate (and former Councilman) Bill de Blasio, one of the city’s rising Democratic stars. Neither SEIU or de Blasio’s office could be reached for comment.

Padernacht said he was not convinced by the arguments being made for him to get out of the race, the primary one being that if he stays in, he will take away votes needed to beat Espada.?

“I don’t agree with their numbers,” he said, adding that he thought there would be a higher turnout for this race than the one in 2008 because there will be much more interest. That race pitted Espada against indicted (and facing trial on corruption charges) Efrain Gonzalez. Espada won, with a little less than 5,000 votes out of of a total of 8,352.

Tirado, the district manager of Community Board 7 (who is on forced leave while working on the campaign), said Rivera asked him on Saturday, during the annual summer barbecue on Mosholu Parkway put on by the Committee of 100 Democrats, if he would step down in the interest of the community and the ouster of Espada.

Tirado who has raised about $2,000 (compared to Rivera’s $60,000-plus), said he had not received calls from any outside politicians or organizations. But he said Rivera told him that he was officially challenging his petition signatures.

(Tirado says he has more than 1,500, while Padernacht, who says he’s also being challenged by three different people – but doesn’t know who – says he has around 4,500. Earlier today, Rivera said he wasn’t sure if or who he would be challenging.)

“I told [Rivera], ‘This is the democratic process and if you feel strongly about it [you should let it take its course],” Tirado said. If others called, he said he would tell them the same thing: he’s staying in the race.

Padernacht, who said he had a long, cordial talk with Tirado at the barbecue on Saturday, agreed, adding that calls for him to step down wreaked of political cynicism. “If I accept their view, I’m accepting a cynical pessimistic view of our community.”

At the press conference this afternoon with Koppell (more on this later), Rivera brushed off concerns that a more crowded race would hurt his chances at victory, but he added that all the challengers could agree on one thing: Espada needed to go.