Biden, who has a double-digit lead over President Donald Trump in every major poll, has said his VP choice will be a woman, and he sent a signal the size of a jumbotron showing his support for Warren when he endorsed her bankruptcy plan after she dropped out of the presidential race in early March.

The decision involved him swallowing his pride because the two had famously clashed over the 2005 bankruptcy reform bill in a public hearing when Biden was a senator who supported the legislation and Warren was a Harvard University law professor testifying against it.

“I’ve endorsed Elizabeth Warren’s bankruptcy proposal, which allows for student debt to be relieved in bankruptcy and provides for a whole range of other issues that allow us to impact how people are dealing with their circumstances,” Biden said in mid-March. “So there’s a whole range of things we agree on.”

Warren’s interest in bankruptcy – she wrote several books on the subject – and other consumer issues led to her advocacy for the creation of the Consumer Financial Protection Bureau, included in the Dodd-Frank Act of 2010. A few months after signing the bill, President Barack Obama appointed Warren as an assistant to the president and special advisor to the secretary of the Treasury charged with overseeing the formation of the new regulator.

Warren has some strikes against her that have tempered expectations of a Biden-Warren ticket. For one, she is not a woman of color at a time when the nation is having a reckoning with systemic racism. About a third of Democrats, among both Black and white Americans in a USA Today/Suffolk poll of 345 Democrats taken during the last week of June, called it “very important” for Biden to pick a running mate who is a woman of color.

Also, Warren is a Democratic senator in a state headed by a Republican governor who will choose her temporary successor. Gov. Charlie Baker has been called a RINO – a Republican In Name Only – and has criticized Trump for his behavior during the pandemic, but that doesn’t mean he’s going to name a Democrat to replace Warren.

Control of the U.S. Senate next year now hangs in the balance, with The Cook Political Report designating five Republican seats as “toss-ups”: Arizona, Colorado, Maine, Montana and North Carolina. But, even if majority control came down to Warren’s seat, state law requires a special election to be held in 160 days – about five months. There is little chance Massachusetts voters would elect a Republican to replace Warren, given the anti-Trump slant of the state.

Or, there could be another solution – it is Massachusetts, after all, where Democrats hold a super-majority in both chambers of the state legislature. In 2004, when John Kerry was the Democratic presidential nominee, legislators passed a bill stripping Republican Gov. Mitt Romney of his ability to make a temporary appointment for Kerry’s Senate seat if he won. Romney vetoed the bill, but it was overridden and became law.

Kerry later lost to George W. Bush, and the law was changed back.

There’s been talk, as well, of Warren filling various positions in a Biden cabinet, including Secretary of the Treasury, so even if she doesn’t get the nod for VP, the replacement issue may still be in play.

After leaving Harvard Law School to become a senator in 2013, Warren became famous for her clashes with the heads of the nation’s largest banks as well as the federal regulators charged with overseeing them. When Warren frames her questions, she starts with a folksy Midwestern style and adds a chaser of eviscerating follow-ups if people give evasive answers.

In 2013, during one of Warren’s first committee hearings, the audience broke into applause – a rarity for a Senate hearing – when she asked regulators including the head of the Office of Comptroller of the Currency to cite one time when they had taken a financial institution to court rather than relying on a settlement. None could give an example.

“We face some very special issues with big financial institutions,” Warren said. “If they can break the law and drag in billions in profits and then turn around and settle, paying out of those profits, they don’t have much incentive to follow the law.”

There was more applause after Warren ended her questioning by saying:

“There are district attorneys and U.S. attorneys who are out there every day squeezing ordinary citizens on sometimes very thin grounds and taking them to trial in order to make an example, as they put it.”

A video of Warren’s 2016 Senate Banking Committee questioning of John Stump, then the CEO of Wells Fargo, has been viewed over 1.8 million times on YouTube. Stumpf led the bank during a time when millions of fake accounts were opened in customers’ names, in some cases damaging their credit, to satisfy his cross-selling goals of having every customer using eight bank products because, as he put it, “eight rhymes with great.”

During the exchange, Warren asked Stumpf if he had returned “a nickel” of the millions of dollars he made as leader of the bank while it fraudulently used its customers’ names. When Stumpf said it was up to his board of directors, she interrupted him to say, “I’ll take that as a no.”

Later in the same hearing, she told Stumpf he should resign. A month later, he did.

Late-night comedian Stephen Colbert described the exchange by saying Warren “tore him a new Stumpf-hole.”

After Stumpf’s successor, Tim Sloan, failed to provide adequate answers in a similar committee hearing in 2017, Warren told him, “You should be fired.” He later resigned under pressure and the Wells Fargo board of directors canceled his $15 million bonus.

Warren spent the first half of her life as a “die-hard conservative,” as a friend told Politico last year. Warren was a registered Republican until 1996, when she was 47, a period that includes her years as a law professor at the University of Texas in Austin.

Warren has said she originally identified as a Republican because she thought it was the party that “best supported free markets,” but that she later came to believe the party was tilted in favor of supporting big corporations over small businesses and middle-class Americans.

Warren often sums it up this way: She went from believing in free markets to believing in fair markets.

The issue of bankruptcy was a major factor in turning Warren into a Democrat. As she researched consumer bankruptcies, she discovered that half of all families filing for bankruptcy did so in the aftermath of a serious medical problem. Of those, three-quarters had medical insurance.

Those research results had echoes of her own experience growing up in Oklahoma as the youngest daughter in a family of four kids where the three older brothers all went into the military. When she was 12, her father had a heart attack that led to the family’s finances being overwhelmed with medical bills. The family’s car was repossessed because they couldn’t pay the loan.

She famously, in her stump speeches, described her family as being “on the ragged edge of the middle class” and “kind of hanging on at the edges by our fingernails.”

They would have lost the house if her mother, a homemaker, hadn’t worked up the courage to go out and get a job at a time when few married women worked, Warren said. They didn’t declare bankruptcy, but it was a difficult time.

Warren often recounted the story on the campaign trail of the scene seared into her childhood memories: Her mother put on her best dress, fixed her make-up, and gave herself a pep talk as she got ready to leave the house for her first-ever job interview: A position answering phones in the catalog-order department at Sears. She got the job, and the family survived on that one paycheck until her father got better and found a job as a janitor that didn’t pay as much as he earned before his heart attack.

A year later, when Warren was 13, she started a job waiting tables at her Aunt Alice’s restaurant, later recounting in speeches how the restaurant was open six days a week. On the seventh day she and her aunt would scrub the floors on their knees to get ready for the next day’s opening.

“I’ve seen the grit and hard work it takes to run a small business up close,” Warren said in a 2017 speech against the Republic tax bill that she said favored big corporations at the expense of small businesses.