WASHINGTON — Sen. Elizabeth Warren of Massachusetts raised $19.1 million in the past three months, her campaign said Monday, a total that places her firmly in the top echelon of the Democratic money race and ahead of her main rival for the party’s progressive wing, Sen. Bernie Sanders of Vermont.

The fundraising haul represents a turnaround for Warren after she raised just $6 million in her campaign’s first three months, before her strategy of eschewing wealthy donors and inundating voters with detailed policy proposals began to pay dividends.

Warren’s campaign team said her fortunes had begun to turn in the last week of March, about a month after her decision to forgo closed-door fundraising events during the primary campaign.

Warren’s total for the second quarter, which ran from April through June, is likely to place her third in fundraising among Democrats over that period.

Two candidates have reported topping $20 million in the second quarter: Mayor Pete Buttigieg of South Bend, Indiana, raised $24.8 million, and former Vice President Joe Biden collected $21.5 million, their campaigns said last week.

Sanders — who has also avoided high-dollar fundraisers — brought in $18 million in the quarter, and Sen. Kamala Harris of California raised nearly $12 million, their campaigns said.

We raised more money than any other 100% grassroots-funded campaign,” Roger Lau, the Warren campaign manager, wrote in an email to supporters Monday, taking an implicit shot at Buttigieg and Biden, who have raked in money on the traditional fundraising circuit.

“You sent a message that Elizabeth’s vision for the future is worth fighting for,” Lau wrote. “And you showed the rich and powerful that change is coming — sooner than they think.”

Warren’s fundraising total is the latest evidence that her policy-driven strategy is resonating with a growing segment of the Democratic base.

In March, her allies openly questioned her plan to reject high-dollar fundraisers and rely on a grassroots base. More specifically, some worried that she would struggle to escape the shadow of Sanders, who had built a seemingly unmatchable fundraising juggernaut behind his progressive brand. Warren’s finance director resigned in March.

Warren has now bested Sanders in fundraising just one quarter later, after months of building momentum. Her growth has been driven by policy announcements that were well-received by progressives, a slew of candidate forums where she earned positive reviews, and moments when she seized on the news of the day — such as when she called for President Donald Trump’s impeachment after the release of the special counsel’s report.

Warren’s improvement in fundraising has coincided with a bump in polling. She has ascended within the crowded primary field to an average of about 13% in recent national surveys, gaining ground on Biden and Sanders.

Harris, meanwhile, has capitalized on her performance in the Democratic primary debate last month, joining Warren in the tier behind the race’s two best-known figures. Warren’s team has repeatedly dismissed the significance of national polling in the early stages of the race and has said that Warren is pursuing a state-by-state strategy.

Warren is expected to continue to try to use policy announcements to create news and drive donations, which will be necessary to sustain her large staff in early primary states. At events in recent months, her “I have a plan” mantra has become a vocal rallying cry among supporters, and proposals like student debt cancellation now elicit sustained applause. Voters repeatedly say that, more than any individual proposal, Warren’s overall policy focus has helped them believe she is prepared for the office.

But the third quarter is a traditionally difficult fundraising period, and Warren must also overcome concerns that linger among Democrats over how she would fare against Trump in a general election. In a Washington Post/ABC News poll published last week, just 7% of Democrats and Democratic-leaning independents said Warren had the best chance to beat Trump next year. (Biden led on that question, with 45% saying he had the best shot.)

Warren collected money in the second quarter from more than 384,000 donors, whose donations averaged $28, her campaign said. She finished the quarter with $19.7 million in cash on hand, less than $100,000 of which is earmarked for the general election, her campaign said.

Warren’s decision to rely on small donations to power her campaign still carries risk, given that some of her rivals are raking in huge amounts of cash at fundraising events with wealthy donors.

She has enjoyed a big financial cushion in the early stages of the race because she transferred $10.4 million to her presidential bid from her Senate campaign account in the first quarter.

But she will need to keep raising money to pay for the expensive campaign operation she has built. Her campaign’s spending in the first quarter of the year, more than $5 million, was the highest in the Democratic field. She had by far the biggest staff in that quarter, according to Federal Election Commission records, with about 160 people on her payroll.

Her staff has grown to 300 since then, her aides said, with 60% of her employees stationed in Iowa, New Hampshire, Nevada and South Carolina, the first states to vote in next year’s primaries. She has built a particularly large operation in Iowa, the first state with a nominating contest.

Instead of courting wealthy donors, Warren has made a habit of placing phone calls to people who give her money online, interactions that have ended with joyful posts on social media. At her campaign events, she sticks around to take pictures with anyone who wants to meet her.

Presidential candidates are required to file their campaign finance reports with the Federal Election Commission by July 15. Those reports will provide details on how the candidates are raising and spending money, including a more detailed picture of how Warren has expanded her campaign operation since the last quarter.

This article originally appeared in The New York Times.