WASHINGTON — Elizabeth Warren is no longer a Democratic presidential candidate, but she looms large over the race between moderate Joe Biden and progressive Bernie Sanders, holding the power to shape it with her endorsement.

Warren offered no hints Thursday regarding whom she’ll throw her support to, saying she wants to “take a deep breath and spend a little time on that” as both candidates showered praise on their former rival in hope of winning her over.

It’s a dilemma. Warren’s policy agenda of “big structural change” to tax the rich and expand the safety net aligns with Sanders’; she’s memorably said that on health policy, “I’m with Bernie.” But she also ran on unifying the party, and the rapidly emerging consensus among Democratic elites is that Biden is their man.

“There are millions of people looking to her for leadership in this moment,” said Aimee Allison, founder of She the People, a group that focuses on empowering women of color.

Any endorsement — or non-endorsement — will disappoint many Democrats. And with coming primaries that could decisively tilt the race toward one of the two remaining men, Warren’s moment of maximum leverage as a former contender may not last long.

“Ideologically she lines up with Bernie Sanders on a number of issues, but she clearly had real differences with him that she only started to outline in the last week or so,” said Mary Anne March, a Boston-based Democratic consultant. “But then, the overriding principle right now for everybody on the Democratic side is to beat Trump, and many have clearly decided that voting for Joe Biden right now is the only way to do that.”

And the other question on many minds is whether Warren will seek concessions for an endorsement — a vice presidential spot, a Cabinet position or promises to govern a certain way.

“They both need her. So the question is: Which one is likely to do more to get her?” Marsh said. “White college-educated women, who really are her fan girls, is a constituency that both candidates want and she has the ability to maybe deliver.”

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Warren’s core base of support is a blend of progressives attracted to her bold agenda and well-educated women who supported Hillary Clinton in 2016. The former group leans toward Sanders, and the latter is tilting toward Biden, if Super Tuesday results are any indication.

A Morning Consult poll this week found that among Warren supporters, 36 percent back Biden and 28 percent support Sanders as their second choices. If Warren were to endorse Biden, he’d add 4 points to his total, while Sanders would add 5 points if he gained her endorsement.

Supporting Sanders may be hard for Warren to explain to some supporters who have been on the receiving end of ugly and sexist remarks from his most extreme online fans, although Sanders has disavowed such “vitriol” and said Wednesday he’s “disgusted” by it.

But backing Biden, who has supported corporate-friendly bills like the 2005 bankruptcy overhaul, would raise questions on the left about her level of commitment to taking on financial elites she says have corrupted Washington and harmed ordinary Americans.

“I would be very surprised if she endorsed Joe Biden,” Allison said, referring to the difference in their policy visions. Sanders and Warren “represent the same wing of the party,” she said. “They’re fighting for similar things around health care and other big structural changes.”

While some believe Sanders hasn’t done enough to condemn the behavior of vitriolic supporters, Allison doesn’t expect that to be the basis of Warren’s decision, saying it underestimates how tough she is.

“In primaries, things can get kind of nasty, but people come together eventually,” she said.

Warren’s predicament is befitting of a candidate who sought to capture votes from the warring left and moderate wings of the Democratic Party and came up short, much to the chagrin of supporters who believed she represented the best of both.

Carleigh Beriont of New Hampshire, who volunteered and knocked on doors for Warren, said in a text message: “From the people I’ve spoken with in states that haven’t voted yet, people are very torn because now they feel like they have to choose between electability (Biden?) and issues (Sanders?) and frustrated by what they’ve seen as a larger narrative by some that tells us we can’t have both (Warren).”

In 2016, Warren resisted immense pressure to endorse Clinton or Sanders during their heated primary battle, disappointing supporters of both candidates. She instead opted to use her leverage to influence the eventual nominee — Clinton — and nudge her toward a more progressive agenda before ultimately helping rally voters to her side.

Many Democrats are eager to see whether she makes a similar play this year.

“Elizabeth Warren has amazing goodwill and leverage right now,” said Adam Green, an activist with the Progressive Change Campaign Committee, a group that supported her run. “She has issues that she cares about and millions of people who have been a part of this. And she will use her leverage to make sure that her issues and those people are respected and advanced in whatever comes next.”

Deepa Shivaram reported from Cambridge, Massachusetts.

Deepa Shivaram contributed.