Tom Hennigan in São Paulo
Brazil's senate is set to suspend President Dilma Rousseff from office on Wednesday after a last-ditch effort by her allies to delay the vote failed.
Just hours after he annulled last month's session in the lower house of congress that approved Ms Rousseff's impeachment, the acting head of the chamber Waldir Maranhão dramatically reversed course on Monday night leaving the path clear for the senate to debate the motion.
The volte-face followed widespread public ridicule and deep anger among the country’s political class who saw Maranhão’s annulment effort as an unconstitutional manoeuvre orchestrated by an administration desperate to stave off its increasingly inevitable demise.
Even before he reversed course the senate had said it would ignore Mr Maranhão’s decision, which cited irregularities in the April 17th session in the lower chamber that overwhelming approved Ms Rousseff’s impeachment.
Before making his move Mr Maranhão met with the president's attorney general José Eduardo Cardozo, who is leading her defence. Mr Cardozo admitted the meeting took place but denied applying any political pressure in favour of the annulment effort.
Then when news emerged later on Monday night of Mr Maranhão’s impending reversal, members of the administration reportedly rushed to his residence in an unsuccessful effort to dissuade him from backtracking.
Monday night’s sudden u-turn stripped the president’s defence of a pretext for asking the supreme court to delay Wednesday’s session in the senate at least until the lower chamber voted again on impeachment, as originally intended by Mr Maranhão.
"This backtracking has taken the wind out of the government's sails and it now seems that the supreme court avenue is closed to it," says David Fleischer, professor of politics at the University of Brasília.
Regardless of the pessimism surrounding its chances of success, attorney general Cardozo launched an 11th- hour bid on Tuesday afternoon to have the supreme court halt the senate vote.
The senate’s session is due to start on Wednesday morning and last over ten hours before a vote is taken. If a simple majority of the 81 senators decide to accept the impeachment motion Ms Rousseff will be suspended from office for up to 180 days during which time the senate must hold a trial on whether to permanently remove her, for which a two-thirds majority is required.
Already a clear majority of senators have expressed their support for impeachment, meaning Wednesday's vote is considered a formality. Once the chamber votes to suspend Ms Rousseff she must be formally informed of its decision. That is expected to take place on Thursday, after which her estranged vice-president Michel Temer will become acting president.
Ms Rousseff and her Workers Party have vowed to fight on and defeat impeachment at the senate trial phase but most analysts say it is unlikely once suspended she will ever return to office.
While suspended she will continue to receive half of her €8,000 a month salary. The senate is still to decide if she can remain in the presidential residence, the Alvorada Palace, and avail of air force jets and helicopters while her ultimate fate is decided.
Ms Rousseff’s supporters mounted roadblocks in Brasília and over a dozen states yesterday in protest at her impending removal but participation was confined to small groups of militant organisations linked to her Workers Party.