MACEIO/BRASILIA, Brazil Dilma Rousseff is not the first Brazilian president forced to contemplate the loyalty of Renan Calheiros on the eve of her possible impeachment.
Nearly 25 years ago, Calheiros, the current president of the Senate who will decide the pace of debate over Rousseff's impeachment, weighed the fate of a fellow politician from his tiny northeastern state of Alagoas: Fernando Collor de Mello.
Calheiros was a key advisor in Collor's successful presidential campaign in 1989. Just three years later, his explosive revelations of government corruption to journalists and congressional investigators helped topple Collor in a corruption scandal.
As the impeachment process against Rousseff moves to the Senate after winning overwhelming support in the lower house of Congress on Sunday, she and her allies may look with trepidation to Calheiros, a crucial but inconsistent ally in the past year.
Calheiros has resisted the rush to remove Rousseff among a large wing of his Brazilian Democratic Movement Party (PMDB), throwing his support behind the idea of new general elections to settle the country's political crisis.
Yet those proposals are distant and theoretical, while the decision before Calheiros is urgent. He faces intense pressure from his own party and others in the opposition to quickly set a date for a Senate vote on whether to accept impeachment charges and put Rousseff on trial.
The precedent of Collor's impeachment suggests a committee will be formed to present a recommendation on whether Rousseff should be tried. This would be voted on by the full chamber within 10 parliamentary sessions - which would be in early May.
The pro-impeachment camp only needs a simple majority in the Senate to open a trial, an easier hurdle than Sunday's lower house vote, which required two-thirds support.
But if Calheiros delays the vote it could give Rousseff vital time to regroup, negotiate and try to swing wavering senators in her favour.
Those closest to Calheiros say his shrewd sense of realpolitik, which has helped him dodge several scandals of his own, makes him reluctant to put his own judgment before the intense political currents of the day.
"Renan could decide the history of the country. And that's exactly what he doesn't want: to be marked as the one who dealt the final blow," said a close confidant in his home state of Alagoas, who asked not to be named. "Because if that works for him, then it's chicanery, and if it goes wrong then he's dead."
Calheiros' aides did not respond to a request for comment, but the Senate leader downplayed his role to reporters on Monday, saying he would neither rush or draw out the impeachment process but would follow the law and the constitution.
Calheiros, 60, is part of a group of politicians known in Brazil as the "dinosaurs", an old guard who entered politics under military rule and consolidated power after the return of democracy in the 1980s with a knack for compromise and sharp survival instincts.
Born in the remote interior of Alagoas, Brazil's third poorest and most violent state, Calheiros' career has been marked by shifting allegiances.
First elected to Congress in 1982, he quickly built a reputation as a power broker and has allied with every Brazilian president since Collor in 1990, even as the ruling ideology shifted to the left under the governments of Rousseff and her predecessor Luiz Inácio Lula da Silva.
Calheiros is also known for close escapes from corruption scandals that could have sunk a less experienced politician.
One incident came in 2007, when a news magazine reported a construction company's lobbyist was paying child support for a daughter Calheiros conceived with a young journalist.
Further allegations of tax fraud and improper business dealings prompted an inquiry by the Senate's ethics committee and calls for his ouster.
Calheiros quit as Senate boss, taking enough heat out of the attacks to gather votes and dodge impeachment.
And by 2013, he was back in charge of the Senate.
When Rousseff's congressional coalition began crumbling and the movement to impeach her began last year, Calheiros came to her aid.
He helped to pass crucial tax measures and delayed an audit into a breach of budgetary laws for which she will now likely be put on trial in his chamber.
But colleagues in his party, the PMDB, which led the impeachment process in the lower house, believe he will not stand in the way of Rousseff being forced from power.
One party leader with close ties to Vice President Michel Temer, who will replace Rousseff if she is impeached, admitted there were divisions in the PMDB but that in the face of significant political change the party sticks together.
To prove the point, the source called Calheiros during the interview. "Lets move ahead together, my friend," he told Calheiros in a light-hearted phone conversation.
On Monday, Calheiros took centre stage in the impeachment saga, meeting with Rousseff and then her arch-rival, lower house speaker Eduardo Cunha, and Ricardo Lewandowski, the Supreme Court justice who would preside over a trial in the Senate.
Regardless of Calheiros' own views, the political momentum is clearly with the pro-impeachment camp.
"I think Renan right now is watching to see who wins," Paulo Pereira da Silva, a union boss and ardent critic of Rousseff, said as votes were being cast in the lower house on Sunday.
"But once the impeachment arrives in the Senate, he will be the first to hang her out to dry."
(Reporting by Brad Haynes in Maceió and Alonso Soto in Brasilia; Additional reporting by Anthony Boadle in Brasilia; Writing by Brad Haynes and Stephen Eisenhammer; Editing by Kieran Murray)
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