Elizabeth Warren is ending her presidential campaign, a dramatic if expected turn after a disappointing stretch of primaries for someone who was once seen as a leading contender for the Democratic nomination.

She announced her decision in a call with staff on Thursday.

"We ran from the heart," she said, according to a person on the call. "We ran on our values. We ran on treating everyone with respect and dignity."

It is not yet clear whether Warren plans to endorse either of the remaining top candidates, Bernie Sanders or Joe Biden. Her endorsement would be undoubtedly influential, but she is in a difficult position, with a raft of supporters who are likely to split between the two candidates.

Among close Warren allies, there has been disagreement in recent days about whether she should endorse Sanders, with whom she is closely aligned ideologically, or try to extract policy commitments or a possible cabinet position from Biden, who for now looks most likely to capture the nomination.

Biden and Warren spoke on Wednesday night, a Biden campaign official said.

Sanders' deputy campaign manager Ari Rabin-Havt said on MSNBC soon after Warren's decision broke that Sanders would "welcome" an endorsement from Warren, but "I think we have to leave that to the Warren campaign."

Warren had said often that she cared more about enacting her agenda than becoming president herself. And she and and her once-ascendant campaign shaped the 2020 primary in that sense, introducing a slate of policies into the Democratic mainstream intended to reshape the American economy and curb the influence of money in government. She made a wealth tax — 2% on fortunes over $50 million, a policy that even Sanders shied away from in 2016 — into a progressive rallying cry, with people at her rallies who dressed as two pennies.

With the funds from the wealth tax, Warren said she would put in place a series of plans focused on education, another departure from many presidential campaigns — enacting universal child to forgiving huge swaths of Americans’ student debt, another idea that had barely been considered among Democrats even two years before.

Her campaign, too, broke new ground. She made a rejection of high-dollar fundraisers a central tenet of her campaign. Instead of calling important donors, Warren made it a point to call up people who had donated small sums instead, and she spent hours after her events taking photos with every single attendee who wanted one — a “selfie line” tradition that is likely to endure in American politics.

And she inspired deep loyalty from her staff and fans, who took to covering everything in the campaign's signature color, "liberty green."

"You know liberty green everything was key here," Warren said on the call with staff Thursday. "My personal favorites included the liberty green boas, liberty green sneakers, liberty green make up, liberty green hair, and liberty green glitter liberally applied. But it was so much more.”

Despite weak showings in early states, Warren had vowed at the start of March to stay in and fight for the nomination through the Democratic convention this summer, hoping to rekindle a campaign whose momentum had once looked unstoppable. But she continued to struggle to pick up delegates into Super Tuesday as Biden stormed to a comeback and consolidated the moderate wing of the party.

Even Warren's blockbuster debate performance a few weeks ago that brought in tens millions of dollars — and almost singlehandedly crushed the candidacy of Michael Bloomberg — wasn’t enough to revitalize the senator's campaign. She continued to struggle to win over people of color, particularly black voters, as well as moderate and working-class white voters.