Brazil's Senate has started a session leading to a vote on whether to send President Dilma Rousseff for a full impeachment trial. If the vote goes ahead against her, it will be Rousseff's final day in office.
Media reports suggest that the opposition has 50 or 51 votes out of the 81 senators supporting a full impeachment trial for Rousseff. A simple majority is all that is needed for the president to be suspended from office and Vice President Michel Temer to be sworn in as president in her place.
Much of the nation was following the debate live on television on Wednesday.
The allegations facing Rousseff are that she violated fiscal rules in handling the federal budget. She is charged with having illegally tapped state banks and taken loans to cover up budget deficits. But the process, which has been going on for months, is taking place against a background of a deep economic recession and revelations of a kickback scheme in state oil company Petrobras.
Rousseff would have to step down immediately although she would probably remain in the official residence. The Senate would determine if she would lose her executive privileges. Under the law, Temer would be in charge for 180 days or until the Senate permanently ousted Rousseff from the presidency.
Vote Wednesday night
Senate President Renan Calheiros has said he wants the vote on impeachment to be taken on Wednesday night. The session began at 10:00 am local time (1300 UTC) in Brasilia.
The Senate is made up of three senators from each of the 26 Brazilian states and three senators from the Federal District. They are elected on a majority basis to serve eight-year terms. Each member of the upper house will get the chance to speak on the impeachment proposal.
The Senate action comes after the lower house voted 367-137 last month in favor of impeachment.
The debate and vote are being closely watched both inside Brazil and internationally. On Monday the head of the lower house annulled impeachment sessions, only to revoke his own decision. Labor unions protested his second decision by burning tires in the streets. Rousseff's supporters have denounced the impeachment process as a coup.
Members of the Landless Workers Movement take part in a protest against the Rousseff's impeachment in Brasilia
Rousseff's defense lawyers have challenged every step of the impeachment process in the Supreme Court. Attorney General Jose Eduardo Cardozo requested another injunction Tuesday. The ruling Workers' Party also requested the high court block Temer from naming ministers before the end of the impeachment trial that could take weeks.
But on Wednesday, a Supreme Court judge denied the injunction to halt the Senate vote. Justice Teori Zavascki ruled the government's argument that impeachment was flawed because it was started out of revenge by the former speaker of the lower house was "legally implausible."
If the vote goes ahead, Rousseff would become the first leader in more than 20 years to be removed from office. It would also end 13 years of rule by the Workers Party in Latin America's largest economy - just months ahead of the summer Olympic Games in August.
Rousseff, a 68-year-old economist, was tortured during Brazil's long dictatorship and accused of belonging to a Marxist guerrilla group. She has said her impeachment is illegal and branded it a "coup."
On Tuesday, anti-impeachment protesters blocked roads with burning tires around Sao Paulo, the capital, Brasilia, and other cities, bringing morning traffic to a stop and prompting clashes with police. The Workers Party and labor unions have called for a national strike.