BRASILIA, Brazil >> They were idealists, united in the struggle against Brazil’s military dictators.

As democracy flourished, so did their careers. One of them, Paulo Ziulkoski, became the leader of an association of Brazilian cities. The other, Dilma Rousseff, rose even higher, becoming the president of Latin America’s largest country.

But their friendship soon fell apart. During a contentious meeting with the nation’s mayors in 2012, Rousseff rejected pleas for a share of Brazil’s soaring oil revenues. After the room erupted in jeers, Ziulkoski said, she stormed up to him, poked a finger in his face and humiliated him with a string of expletives.

“I never imagined a president could utter such words,” Ziulkoski said, noting that dozens of mayors have abandoned Rousseff and her party. To Ziulkoski, the public dressing down was the kind of rupture that symbolized “the beginning of the end for her administration.”

As Rousseff wages a last-ditch battle to stave off impeachment and save her presidency, she has accused her rivals in Congress of creating turmoil, saying they are orchestrating a coup d’etat to oust her.

More than two-thirds of Brazil’s lower house voted last month to approve an impeachment measure on charges that she illegally borrowed from state banks to plug budget holes. (She is not accused of stealing for her personal enrichment.) Many experts say the next step, a trial in the Senate that could begin in the coming weeks, will probably end in her removal.

“I will struggle with all my might until the coup-mongers are defeated,” Rousseff said in an interview.

But many political analysts say Rousseff’s slow-motion downfall can also be tied to an autocratic persona and a go-it-alone work style that has driven away scores of political allies, former staff members and Cabinet ministers, many of whom have endured searing episodes of public humiliation.

“She’s alienated so many politicians and squandered the good will of so many people, in part because of her terrible political skills but also because of her arrogance,” said Edson Sardinha, editor of Congresso em Foco, a magazine that focuses on government corruption. “In her hour of need, very few people are willing to run to her defense.”

The upheaval goes far beyond Rousseff’s leadership style. Brazil is enduring its worst economic crisis in decades, with millions of people falling out of the middle class into poverty. Inflaming their rage, political elites of every stripe have engorged themselves in a multibillion-dollar graft scheme engulfing the national oil company.

Rousseff, who has been politically battered by the scandal, said she was the victim of a naked power grab and sexist assumptions of how a woman should lead. She also said she was a convenient scapegoat for something she cannot control: the global plunge in commodity prices that has sent the economy into a tailspin.

But her vow to bring millions of Brazilians into the streets in her defense has produced little popular support. Siding with her opponents are scores of onetime allies — including five former ministers in her administration — the nation’s vice president and six justices on the Supreme Court who were appointed by Rousseff or her most powerful defender, former President Luiz Inacio Lula da Silva.

In more than five years in office, Rousseff has largely refused to meet with members of Congress, both opponents and allies, eroding the majority support she once enjoyed in the lower house. The aggrieved include Eduardo Suplicy, a former senator and beloved figure in Rousseff’s Workers’ Party, who said she had turned down multiple requests for a meeting.

“In politics, either you talk or you die,” said Alfredo Nascimento, a former transportation minister. In April, he voted for her impeachment.

“I can’t support a president who is incapable of governing,” he said.

In Brasilia, the capital, most everyone can recount stories about Rousseff’s intolerance for dissent and her short fuse. The anecdotes include the time she smashed an office computer in a pique of anger, her refusal to meet with indigenous leaders or gay rights activists and the castigation of aides for the smallest of infractions.

She is also finding little sympathy from the Brazilian news media, which has long viewed her as cold and condescending — a marked contrast to the charismatic, backslapping approach of da Silva.

Some agree that Rousseff is being judged by a double standard that has unfairly tarnished powerful women around the world. Would she be considered so obstinate and uncooperative if she were a man? Or would she simply be called a strong, decisive leader?

“The president is enduring all the stereotypes and prejudices of Brazil’s highly patriarchal and oligarchic society,” said Rosana Schwartz, a historian and sociologist at Mackenzie Presbyterian University in Sao Paulo. “I’ve even heard people say, ‘We will never again vote for a woman.’”

In recent weeks, at least 135 mayors aligned with the Workers’ Party have changed their party affiliations — about a fifth of the nation’s mayors who had been elected on the party’s ticket. Among them are Joao Paulo Ribeiro, 31, the mayor of a small city who said he had grown weary of the attacks by residents and even friends who questioned his association with Rousseff’s party.

“I have to listen to the people,” said Ribeiro, who changed parties last month, hoping to improve his chances for re-election in October.

It is not as if the political figures lining up to oust Rousseff are viewed as saviors. Many of them are battling serious accusations of corruption, and they were in positions of great power as the country’s once-enviable economy ran aground.

Rising unemployment and the broad unrest over Brazil’s economy only added to the strains between Rousseff and Congress. Had the economy been ascendant — as it was in 2005 when her predecessor, da Silva, became embroiled in a vote-buying scandal — she might have emerged unscathed.

The end of Brazil’s bonanza complicated the patronage used to navigate the fractious legislature, in which more than two dozen parties fight for government funding.

“We have a political system based on extracting money from the economy and transferring it to political parties to finance elections,” said Rubens Ricupero, who served as finance minister in the mid-1990s.

Many Brazilian economists and policymakers contend that the economic crisis was largely a product of Rousseff’s own making. She increased the government’s footprint in the economy, spending large amounts on favored industries and corporations to build up national champions.

That not only produced an array of big, unfinished projects and bad debt, which now hobbles the state-owned banks, but also opened the door to large-scale corruption.

“Brazil insisted in carrying out an industrial policy devoid of logic,” said Arminio Fraga, a former governor of the Central Bank of Brazil. “When the government offers companies all sorts of advantages, through protection, subsidies and contracts, it creates enormous space for this sort of thing.”

Nearly two-thirds of the 594 members in Congress face serious charges like bribery, electoral fraud, kidnapping and homicide, among them Eduardo Cunha, the speaker of the lower house leading the impeachment effort. He has been accused of stashing $40 million in bribes.

Rousseff has not been accused of graft, though many people question her innocence, given her role as chairwoman of the national oil company at a time when the epic kickback scheme was being hatched.

In an interview, Rousseff brushed off suggestions that her disdain for retail politics and the horse trading required to pass legislation had contributed to her woes. She defended her decision to ignore members of Congress.

“There were certain types of blackmail negotiations I would not engage in,” she said.

For a time, the Brazilian public viewed her steely resolve positively. During her first year in office, Rousseff’s popularity stood at 77 percent, among the highest in recent history. These days, that figure is in the single digits.

© 2016 The New York Times Company