The two men were born a decade apart in Queens, New York, one the heir to a real estate fortune and the other to a political dynasty. Donald Trump went on to be president, and Andrew Cuomo became governor, like his father.

Over the course of their long and controversial careers, both men have seemed untouchable. But thanks to the recent work of one lifelong public servant, who was born into a big family in Brooklyn without legacy money or power, each man is suddenly facing a moment of unaccustomed accountability.

The state attorney general, Letitia James, the first woman of color ever to hold statewide elected office in New York, blasted a hole in the fable of Cuomo’s pandemic leadership with a report in January showing the state was under-reporting deaths in nursing homes by as much as half.

A quick succession of sexual harassment claims against Cuomo in the ensuing weeks has knocked him from his political perch and left open the question of whether he will withdraw his 2022 re-election bid – or even resign before his current third term ends.

Trump might be in even greater peril. Since 2019, James’s office has been conducting an investigation of business practices inside the Trump Organization and family. Trump has fought fiercely in court, but month after month, James has succeeded in unearthing financial records that appear to be adding up to a giant legal hazard for the former president, analysts say.

“He should be very concerned,” said George Albro, co-chair of the New York Progressive Action Network who has known James going back to when he was a union officer in New York City and she was a public defender. “She’s going to take this to its logical conclusion.”

The Trump case and the Cuomo nursing home scandal have generated a torrent of national attention for James, with people outside New York politics wondering how a single state officer could make such big legal waves.

People who know her from her time as public advocate in New York City – when she was the first woman of color to be elected citywide – and her time as a city council member before that nod in recognition: that’s Tish.

As state attorney general, James has aggressively pursued a full catalogue of progressive causes.

She sued the police department over brutality against people of color, blocked unlawful evictions during the pandemic, won a major sexual harassment settlement for women in the construction industry, filed an amicus brief before the supreme court opposing a rushed census, and sued to dissolve the National Rifle Association.

She also sued Amazon for allegedly failing to protect workers, sued Facebook as an alleged monopoly and investigated Google on similar grounds. She has asked federal regulators to clamp down on toxins in baby food and called for student debt relief.

“I see the law both as a shield and as a sword,” she said in a public discussion last year about Black leadership. “And so I wake up every day with a fire in my belly, and I march into the office – well, I actually march into my kitchen – and the question is, what can I do today to make a difference in the life of somebody? Who can I sue?”

James has acknowledged past critics who thought that she filed too many lawsuits without making enough stick. But she argues that “the law should be a tool for social change” – and with the pressure she has exerted on Trump causing visible stress among family members, the impact of her efforts is plain and the public mood is enthusiastically with her.

That kind of momentum has led to speculation about what might be next for the political pioneer with impeccable grassroots credentials who maintains a huge store of goodwill in New York City as well as a disarming, down-to-earth approach on and off the campaign trail.

“Everyone still calls me Tish,” she told Melva M Miller, chief executive officer of the census watchdog Association for a Better New York, in a public forum last year. “I still have to do my laundry later – I’m still Tish. I have to go to the grocery store – I’m still Tish.”

James, 62, one of eight children, went to Brooklyn public school, graduated from the City University of New York’s Lehmann college and earned a law degree at Howard University, the historically Black university in Washington DC.

Her earliest memory of the legal system, she has said, was seeing a court officer verbally abuse her mother at a hearing for a brother.

“When I looked around the courtroom, all the defendants and all the family members looked like me, but everyone in a position of power did not, and there was something really unbalanced about that and unfair about that,” James told Miller.

Before her election to the New York city council in 2003, James worked as a public defender, as counsel to the speaker of the state assembly and as an assistant attorney general for Brooklyn, where she targeted predatory lenders, advocated for working families and brought the first case against the New York City police department for so-called stop-and-frisk abuses.

She lost a primary race to join the city council, but was able to resume her bid when the incumbent was shot and killed inside city hall. In her 10 years on the council, she emerged as an advocate for police reform and for better public housing.

She also showed a fearlessness about taking on powerful political figures, helping to lead the charge against an effort by the then mayor, Michael Bloomberg, to change city rules and seize a third term in power (a fight Bloomberg won).

Some political allies wondered, however, whether James’s posture of antagonism towards the powerful would apply to Cuomo, who cleared the path for her political future by endorsing her to be attorney general.

As a candidate under Cuomo’s protection, James insisted she was “unbossed and unbought” by the governor. The results of her bombshell investigation of how the Cuomo administration failed to report Covid-19 nursing home deaths shows she meant those words, said Albro.

“She told us that she would be independent of the governor and I think she’s proven that,” he said.

Her battle against Trump has the potential to elevate James’s profile – and prospects – even further, encouraging open speculation about whether she might even succeed the governor whose alleged misconduct she helped expose. Before he was elected governor, Cuomo was state attorney general – the very job James now holds.

“I think she wants to be governor, I think that’s clear, and she’d be a formidable candidate,” said Albro.

“I think she’d be a formidable candidate because she is very well liked and known in the city and that’s a big chunk of the vote.”