Brazilian President Dilma Rousseff, appearing at a meeting Tuesday with the Secretary General of the Organization of American States, faces what could be her final hours in power as the Senate prepares to vote on whether to suspend her from office for an impeachment trial. (Evaristo Sa/AFP/Getty Images)

Less than 24 hours after attempting to annul an impeachment vote against President Dilma Rousseff, the interim speaker of Brazil’s lower house changed his mind, torquing the country’s political system with yet another surprise.

Waldir Maranhão, who was named interim speaker of Brazil’s Chamber of Deputies just last week, said in a terse letter addressed to Senate President Renan Calheiros late Monday night that he had withdrawn his attempt to cancel last month’s vote to put Rousseff on trial. Maranhão gave no explanation for his decision, but his party had reportedly threatened to kick him out earlier in the day.

“I revoke my decision,” he wrote.

The announcement was another setback for Rousseff, with senators scheduled to vote Wednesday evening and her impeachment looking all but certain. If a simple majority of Brazil’s 81 senators vote to put her on trial, she will be suspended from office.

Rousseff is facing impeachment because of accusations that she used unauthorized loans from government banks to cover budget shortfalls and pay for popular social programs. Senators must decide whether that amounts to what Brazilian law considers a “crime of responsibility.” The president’s opponents say she misled lawmakers and the Brazilian public to conceal her mismanagement of government finances.

Rousseff insists that she did nothing wrong and that her predecessors have used the same budgetary tactics.

She appeared to get a reprieve Monday when Maranhão abruptly announced that he had accepted a request by Attorney General José Cardozo, who is defending Rousseff, to negate the April 17 impeachment vote in the lower house because of alleged irregularities in the proceedings.

The annulment attempt sent lawmakers scrambling in Brazil’s National Congress, as Rousseff’s opponents bitterly denounced Maranhão and legal experts questioned his authority to cancel a vote that had already taken place.

By the afternoon, his annulment attempt was already falling apart. Calheiros announced to an uproar that he would ignore Maranhão’s annulment attempt and proceed with the impeachment vote.

“To accept this game-playing with our democracy would make me personally responsible for a delay in the process,” he said.

Maranhão then held a news conference saying that he would stand firm and that his annulment attempt was a move “to save democracy.”

“We are not and will not be at any moment playing at democracy,” he said.

Waldir Maranhao, the acting speaker of the lower house of Brazil’s Congress. (Eraldo Peres/Associated Press)

But by late Monday night he had changed course yet again, annulling his annulment and causing more political chaos.

Elected deputy speaker of the house, Maranhão took over last week when speaker Eduardo Cunha was suspended by Brazil’s Supreme Court. Cunha faces corruption charges at the court for his alleged role in the enormous graft scandal at state-run oil company Petrobras. Maranhão has also been named in the investigation.

Brazil’s Senate will begin debating Rousseff’s impeachment Wednesday morning, with a vote scheduled for 6 p.m. that would decide whether to put her on trial. Senators would have 180 days to determine whether to make her removal permanent. Vice President Michel Temer would replace her if she is suspended.