WASHINGTON — Senator Elizabeth Warren, whose full-throated opposition to high-dollar fund-raising events was a central tenet of her presidential campaign, has agreed to host such a gathering of donors for Joseph R. Biden Jr., the presumptive Democratic nominee, who is considering her to be his running mate.
The online event is set to take place on June 15, according to three people with knowledge of the plans, who spoke under condition of anonymity to share the details.
During her presidential run, Ms. Warren explicitly vowed not to attend private fund-raisers or dial up rich donors. A Massachusetts progressive, she championed tax increases on the wealthy and at times sharply criticized big-money donors. Her rise in public opinion polls last summer deeply concerned many veteran Democratic donors, particularly those on Wall Street and in the banking sector who believed she would damage their industries.
Ms. Warren’s spokeswoman declined to comment. Biden campaign officials did not respond to requests for comment.
Ms. Warren built a network of high-dollar donors as a senator from Massachusetts and previously attended fund-raising events, building up her own campaign war chest before she entered the Democratic presidential race. But in late February 2019, as she sought to gain traction in online presidential fund-raising, especially among progressives who Senator Bernie Sanders was also courting, she ruled out big-money events.
“That means no fancy receptions or big money fund-raisers only with people who can write the big checks,” Ms. Warren said in an email to supporters at the time. “It means that wealthy donors won’t be able to purchase better seats or one-on-one time with me at our events. And it means I won’t be doing ‘call time,’ which is when candidates take hours to call wealthy donors to ask for their support.”
Ms. Warren will now mine her old donor network to help Mr. Biden as she maneuvers to become his running mate, a position that she has said she would accept if asked.
While she remains ideologically to Mr. Biden’s left, Ms. Warren has edged closer to some of his politically pragmatic positions. Ms. Warren, a supporter of a single-payer “Medicare for all” system, has voiced support for a proposal more in line with Mr. Biden’s position of expanding the Affordable Care Act.
All of this follows Ms. Warren, before and during the 2020 presidential primaries, offering herself as a candidate who could represent Democrats’ dreams, not their fears that President Trump would win a second term if the party nominated anyone other than Mr. Biden.
“We can’t choose a candidate we don’t believe in just because we’re too scared to do anything else,” she said during her stump speeches last summer and fall.
Ms. Warren struggled to raise money at the outset of her presidential campaign. But after announcing she would refuse to grant private audiences to large donors or conduct high-dollar events, her fund-raising took off.
She raised $115.8 million during her campaign — $66.5 million of which came from donors who gave less than $200.
Before running for president, Ms. Warren had a record as a strong fund-raiser: During her 2018 Senate re-election bid, she raised $30.8 million for a race in which she faced little serious competition. During her first Senate race, in 2012, she raised $42.5 million.
While she did not hold private fund-raising events for her own campaign, Ms. Warren did appear at multiple such events for the Democratic National Committee. She also, before launching her presidential campaign, contributed funds she’d raised from high-dollar donors to state Democratic parties.
Mr. Biden’s other rivals have aided his fund-raising since he became the party’s presumptive nominee. Former Mayor Pete Buttigieg of South Bend, Ind., raised $1 million in a “grass roots” online fund-raiser on Friday. Mr. Buttigieg is scheduled to appear at more fund-raising events with Mr. Biden next week, as is Senator Amy Klobuchar of Minnesota. Senator Kamala Harris of California, businessman Andrew Yang and Senator Kirsten Gillibrand, all former rivals, are set to appear at Biden fund-raising events in June.
Mr. Sanders sent a fund-raising appeal for Mr. Biden to his donor list, but declined to share his list with the Biden campaign.