The decision comes two days after a disappointing Super Tuesday for Sen. Elizabeth Warren.

WASHINGTON — Elizabeth Warren, who electrified progressives with her “plan for everything” and strong message of economic populism, dropped out of the Democratic presidential race on Thursday, days after the onetime front-runner failed to win a single Super Tuesday state, not even her own.

For much of the past year, her campaign had all the markers of success, robust poll numbers, impressive fundraising and a sprawling political infrastructure that featured staffers on the ground across the country. But once voting began in February, she never found a reliable base of supporters as Democrats coalesced around Vermont Sen. Bernie Sanders, her progressive rival, and former Vice President Joe Biden, who established himself as the leading centrist in the race.

“I refuse to let disappointment blind me — or you — to what we've accomplished," Warren told her campaign staff on a call Thursday. “We didn't reach our goal, but what we have done together — what you have done — has made a lasting difference. It's not the scale of the difference we wanted to make, but it matters."

Warren's exit leaves the Democratic field with just one female candidate: Hawaii Rep. Tulsi Gabbard, who has collected only one delegate toward the nomination. That is a frustrating twist for a party that once boasted the most diverse presidential field in history and harnessed the votes and energy of women to retake control of the House, primarily with female candidates, in 2018.

Despite Warren's disappointing finish, she offers the potential of a coveted endorsement to Sanders and Biden, who are effectively the last candidates in the Democratic contest. She spoke with both men on Wednesday, according to their campaigns. She hasn't made a decision and is assessing who would best uphold her agenda, according to a person familiar with her deliberations who spoke on condition of anonymity to discuss private conversations.

In an interview after Warren's departure was announced, Toni Van Pelt, the president of the National Organization for Women, urged her not to back Sanders.

“She has a lot of leverage right now. We do trust her to make the right decisions on how to proceed. But we’d like her not to rush into this,” Van Pelt said. “We think that our constituents, our members, will not necessarily think of Sanders as the best choice. We wouldn’t have the Violence Against Women Act if it wasn’t for Biden’s leadership. So, we know that he’s performed. Sanders doesn’t have a record. He’s really, as far as we know, done next to nothing for women and for our issues and for the things that are our priorities.”

Warren's campaign began with enormous promise. Last summer, she drew tens of thousands of supporters to Manhattan's Washington Square Park, a scene that was repeated in places like Washington state and Minnesota.

She had a compelling message, calling for “structural change” to the American political system to reorder the nation's economy in the name of fairness. She had a signature populist proposal for a 2% wealth tax she wanted to impose on households worth more than $50 million that prompted chants of “Two cents! Two cents!" at rallies across the country.

Warren hit her stride as she hammered the idea that more moderate Democratic candidates, including Biden, weren’t ambitious enough to roll back President Donald Trump's policies and were too reliant on political consultants and fickle polling. And she drew strength in the #MeToo era, especially after a wave of female candidates helped Democrats take control of the U.S. House in 2018.

But there was also tumult, notably after she released a DNA test in response to goading by Trump to prove she had Native American ancestry. Instead of quieting critics who had questioned her claims, however, the test offended many tribal leaders who rejected undergoing the genetic test as culturally insensitive, and it didn’t stop Trump and other Republicans from gleefully deriding her as “Pocahontas."

Warren couldn't consolidate the support of the Democratic Party’s most liberal wing against Sanders.

Both supported universal, government-sponsored health care under a “Medicare for All” program, tuition-free public college and aggressive climate change fighting measures as part of the “Green New Deal” while forgoing big fundraisers in favor of small donations fueled by the internet.

Warren's poll numbers began to slip after a series of debates in which she repeatedly refused to answer direct questions about if she'd have to raise taxes on the middle class to pay for Medicare for All. Her top advisers were slow to catch on that not providing more details looked to voters like a major oversight for a candidate who proudly had so many other policy plans.

When Warren finally moved to correct the problem, her support eroded further. She moved away from a full endorsement of Medicare for All, announcing that she'd work with Congress to transition the country to the program over three years. In the meantime, she said, many Americans could “choose” to remain with their current, private health insurance plans, which most people have through their employers. Biden and other rivals pounced, calling Warren a flip-flopper, and her standing with progressives sagged.

Sanders, meanwhile, wasted little time capitalizing on the contrast by boasting that he would ship a full Medicare for All program for congressional approval during his first week in the White House. After long avoiding direct conflict, Warren and Sanders clashed in January after she said Sanders had suggested during a private meeting in 2018 that a woman couldn’t win the White House. Sanders denied that, and Warren refused to shake his outstretched hand after a debate in Iowa.

Warren got a foil for all of her opposition to powerful billionaires when former New York Mayor Mike Bloomberg entered the race. During a debate in Las Vegas just before Nevada's caucus, Warren hammered Bloomberg, and the ex-mayor's lackluster response touched off events that ended with him leaving the race on Wednesday.

For Warren, that led to a sharp rise in fundraising but didn't translate to electoral success. She tried to stress her ability to unite the fractured Democratic party, but that message fell flat.

By South Carolina, an outside political group began pouring more than $11 million into TV advertising on Warren's behalf, forcing her to say that, although she rejected super PACs, she'd accept their help as long as other candidates did. Her campaign shifted strategy again, saying it was betting on a contested convention.

Still the longer Warren stayed in the race, the more questions she faced about why she was doing so with little hope of winning — and she started to sound like a candidate who was slowly coming to terms with that.

“I’m not somebody who has been looking at myself in the mirror since I was 12 years old saying, ‘You should run for president,’” Warren said aboard her campaign bus on the eve of the New Hampshire primary. “I started running for office later than anyone who is in this, so it was never about the office — it was about what we could do to repair our economy, what we could do to mend a democracy that's being pulled apart. That’s what I want to see happen, and I just want to see it happen.”