RIO DE JANEIRO — Nearly two years after former President Dilma Rousseff was impeached by Congress in one of the most stunning political downfalls in Brazil’s history, the nation’s first female leader is hoping to return to the capital as a senator.
Ms. Rousseff this week formally announced her intention to run for a Senate seat representing the state of Minas Gerais, where she was born. The race is likely to pit her against the incumbent, Senator Aécio Neves, whom she narrowly defeated in the 2014 presidential election.
If she wins, Ms. Rousseff would become the latest controversial former president in the region to return to politics as a senator.
Former Presidents Álvaro Uribe Vélez of Colombia and Cristina Fernández de Kirchner of Argentina became high-profile opposition figures in Congress after each had served two presidential terms.
“I think I can make a great contribution for the country from the perspective of Minas Gerais,” Ms. Rousseff said in an interview Friday night. “Above all, I want to be a voice defending the expansion of democracy in Brazil.”
Ms. Rousseff said she believed her image among voters had improved amid a torrent of scandals that had embroiled several of the lawmakers that led the process to oust her, which she considers a coup.
If elected, Ms. Rousseff said she would fight to reduce inequality and expand access to education, two of the core initiatives her Workers’ Party championed while it governed Brazil from 2003 to 2016.
“Today we are witnessing significant backsliding across the country,” she said. “The poorest people are enduring the consequences of the policies of this government.”
Ms. Rousseff will probably be the highest-profile name on the Workers’ Party ballot in October, when the presidency will also be in contention.
It is unclear who the leftist party will field for the presidential race. Its plan to get Luiz Inácio Lula da Silva, Ms. Rousseff’s predecessor, elected to a third term, was derailed this year after he started serving a 12-year sentence on corruption charges.
Ms. Rousseff, 70, could become the second former Brazilian president elected to the Senate after having been impeached since democracy was restored in the mid-1980s. Former President Fernando Collor de Mello, who resigned in December 1992 while he was being impeached for corruption, has been in the Senate since 2007.
Laura Carvalho, an economist at the University of São Paulo who recently published a book critical of the economic policy pursued by Workers’ Party governments, said Ms. Rousseff could become an influential voice again.
“Dilma would have enormous weight in economic and political debates over the next four years, in large part because she brings the experience of having served as president,” she said. “I wouldn’t be surprised if she turns out to be a better senator than president.”
Ms. Rousseff has maintained a relatively low profile since she was removed from office in August 2016 after lawmakers determined that she had improperly tapped public bank reserves to paper over budget shortfalls.
Since then, she and Mr. Neves, a center-right politician from the Brazilian Social Democratic Party, have both been charged in corruption cases.
Last year, investigators obtained a recording in which Mr. Neves is heard requesting a large bribe from a prominent businessman. While he has denied wrongdoing, the Supreme Court in April determined there was enough evidence for the case to proceed.
Ms. Rousseff was among the defendants charged in September in a case that portrayed the Workers’ Party as a criminal organization presiding over a massive kickbacks scheme. She has maintained the allegations against her are unfounded.
Manuela Andreoni contributed reporting.