Brasília, Brazil (CNN) President Dilma Rousseff insisted Monday she had committed no crime and said she was proud that she'd been "faithful to my commitment to the nation."

Brazil's post-Olympic high came to an end as Rousseff's impeachment trial began. Her remarks from the Senate floor suggested the suspended president had no intention of accepting the bid for her impeachment without a fight.

"I'll plan and fight for democracy," she said. "I don't fight for my term for the power, but I fight for the democracy for truth and justice and the people of my country."

It's not clear if an impassioned speech will do any good. The tide of opinion is against her, and the appearance is widely expected to be her last public address.

"I fear the death of democracy" - suspended #Brazil president @dilmabr says as she speaks from senate floor during her impeachment trial

It's a jarring return to reality for the South American nation, with the final vote in the drama following the celebrations that came with Rio de Janeiro hosting the 2016 Summer Olympics.

The impeachment process has dragged on for months, predating the Olympic torch lighting ceremony -- a glitzy showpiece that, despite orchestrating, Rousseff was barred from attending. It's a political crisis that ordinary Brazilians could do well without -- the country is trying to pick itself out of recession.

'It's not an impeachment'

Rousseff calls the impeachment an attempt at a power grab by her rivals, saying her government has long been the target of political sabotage.

"When Brazil or when a president is impeached for a crime that they have not committed, the name we have for this in democracy, it's not an impeachment, it is a coup," she said in May after the Senate voted to launch the proceedings.

The heir-apparent to former President Luiz Inacio Lula da Silva, Rousseff was re-elected by a narrow margin in 2014, but soon a recession and a cross-party corruption scandal put an end to any political goodwill she might have earned.

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She has been suspended from all official duties and has -- for the time being, at least -- been replaced by her former deputy, Michel Temer, a man she accuses of stabbing her in the back.

The final vote to impeach, which needs to be ratified by a two-thirds majority of 81 senators (54 votes), is expected Tuesday.

If the vote passes -- and most observers expect it to do so easily -- Temer will become the country's new president until 2018's general election, at least. He would inherit a tattered economy along with the keys to the presidential palace in Brasilia.

What do the polls say about Rousseff?

Rousseff's popularity soared when she was elected Brazil's first female President in 2010.

Lately, her approval rating has been hovering around 10%, according to recent polls.

For some context, pollster Ipsos said in a report in April that Rousseff's approval rating was around 15%, while former US President Richard Nixon's approval rating was 25% before he resigned and former US President Bill Clinton's approval rating was 65% before his impeachment.

Photos: Brazilians protest -- for and against -- president's impeachment Brazilians celebrate the impeachment of President Dilma Rousseff in Sao Paulo, Brazil on May 12, 2016. The former leader denounced the move as "a coup." Hide Caption 1 of 6 Photos: Brazilians protest -- for and against -- president's impeachment Interim president Michel Temer said Brazil must be united to move forward. "We don't have a lot of time. We have to be committed so we can implement the reforms that the country needs," he said. Five things to know about Temer Hide Caption 2 of 6 Photos: Brazilians protest -- for and against -- president's impeachment The decision to impeach Rousseff came after about 20 hours of debate in the Senate. She's been suspended for 180 days, and while she'll retain the title of President, she won't perform any of the duties of the office. Rousseff: What she keeps, what she loses Hide Caption 3 of 6 Photos: Brazilians protest -- for and against -- president's impeachment Riot police arrest a Rousseff supporter during a protest in Sao Paulo, Brazil on May 12. Hide Caption 4 of 6 Photos: Brazilians protest -- for and against -- president's impeachment Fifty-five of 81 members of Brazil's upper house voted in favor of the motion to impeach Rousseff on Thursday. Twenty-two voted against. Hide Caption 5 of 6 Photos: Brazilians protest -- for and against -- president's impeachment Along with the precarious state of the Brazilian economy, the country faces a number of other, high-profile challenges, from dealing with the Zika virus to a fraught 2016 Olympics, which are due to open in Rio de Janeiro in August. Hide Caption 6 of 6

What is she accused of?

She faces accusations that she doctored accounts ahead of her re-election in 2014 to hide a budget shortfall and to keep funding popular social programs. Rousseff maintains she didn't do anything illegal and is expected to counter that some of the lawmakers investigating her are under investigation for corruption.

"I have made mistakes, but I have not committed any crimes. I am being judged unjustly, because I have followed the law to the letter," Rousseff has said.

Her government has been fighting corruption allegations for a while.

A sweeping investigation into a multimillion-dollar kickback scheme at the state-run oil company Petrobras embroiled dozens of the country's leading businessmen and politicians. While she isn't accused directly of profiting, Rousseff was the chairwoman of the state oil company during many of the years of the alleged corruption.

How much of her term is left?

Rousseff's term is set to end in December 2018. Right now, she's suspended for up to 180 days, and Temer is the acting president. If she's found guilty in the impeachment proceedings, she'll be removed from office. She insists she'll stick around to see out her term, but Tuesday's vote will determine that.

Who is behind the impeachment?

Again, like many things in Brazil's tumultuous political landscape, it depends on whom you ask. But in the country's lower house, one man had been leading the charge: Eduardo Cunha.