Senator Elizabeth Warren of Massachusetts meets with Supreme Court nominee Merrick Garland, chief judge of the D.C. Circuit Court, April 14, 2016 on Capitol Hill in Washington, D.C. Garland continued to visit senators after being nominated by President Barack Obama to succeed the late Justice Antonin Scalia on the high court. (Olivier Douliery/Abaca Press/TNS)
Senator Elizabeth Warren of Massachusetts meets with Supreme Court nominee Merrick Garland, chief judge of the D.C. Circuit Court, April 14, 2016 on Capitol Hill in Washington, D.C. Garland continued to visit senators after being nominated by President Barack Obama to succeed the late Justice Antonin Scalia on the high court. (Olivier Douliery/Abaca Press/TNS) Credit: Olivier Douliery — Abaca Press — tns

Washington — As the rift between Sen. Bernie Sanders’ supporters and Hillary Clinton’s expands into anger and even some violent threats, many Democrats are pointing to a potential bridge: Sen. Elizabeth Warren.

The Massachusetts senator is one of the few figures in the Democratic Party who carries as much credibility with the party’s restive left wing as Sanders, of Vermont.

But as Democrats ask if Warren can help corral Sanders’ backers, a second question emerges: What does Warren want?

The endgame of the Democratic primaries will shape the bigger contest for influence in the party over the next four years, one in which Warren and Sanders could prove to be allies — or rivals. That potential adds even more intrigue to an already fraught situation.

“Elizabeth is more focused on the day-to-day policy battles than Bernie is, but yet she will inherit, I think, the political power that Bernie woke up out in the country,” said a longtime Warren confidant who requested anonymity to discuss the sensitive intra-party struggle.

“Bernie himself will be a much more significant figure on his return to the Senate than he was this term. Assuming they’re able to work together at some level, that creates greater power,” he added.

Warren already has taken public steps to position herself as an influential player. A series of Twitter wars with Donald Trump, in which she has attacked the New York businessman as a phony populist, has enhanced her already high popularity among Democrats.

“@realDonaldTrump spews insults and lies because he can’t have an honest conversation about his dangerous vision for America,” Warren wrote during a typical exchange.

The Democratic National Committee used the tweets in a fundraising email on Wednesday, with the subject “Elizabeth Warren is in, are you?”

Warren, who carefully calculates when and how she uses her voice, declined an interview request. Clinton’s campaign did not respond to requests for comment.

Key to Warren’s power is the belief among loyalists that she cannot be co-opted. And even as she has signaled a willingness to help Clinton win the presidency, Warren’s alliance with the former secretary of state is unlikely to be permanent or easy.

“It’s no mystery that Elizabeth has skepticism about Hillary Clinton’s positions on Wall Street matters and the people who advise her on those issues,” said Dennis Kelleher, a close Warren ally since the 1990s who heads a Wall Street watchdog group called Better Markets.

“Clinton’s got an interest in bringing Warren into the fold, and Warren’s got an interest in bringing Clinton to the right place on the issues she cares about,” he added.

Minding that relationship likely will be a continuing quandary for Clinton, much as it has been for President Obama.

Some Democrats are urging Clinton to ask Warren to be her running mate — a scenario that several senior Democrats see as unlikely to suit either of them.

“Elizabeth is someone who’s used to challenging and prodding the establishment, not speaking for it,” said David Axelrod, the former strategist and senior White House aide to Obama.

“Vice president is a job that requires you to speak for the administration, and I’m not sure she’d want to speak for an administration that she’s not leading.”

More likely, Clinton will have to decide how much informal influence to give Warren in crafting policy in her campaign and, potentially, her administration.

One issue that Warren already has indicated she views as key will be personnel. Kelleher believes it will be especially hard for Clinton to win Senate approval for nominees to the Treasury Department and other key financial posts if they have ties to big banks or Wall Street, a litmus test that has seldom been applied in prior Democratic administrations.

Overall, the relationship may work better if Warren stays an outside ally, rather than a figure inside the administration, say people who have worked with both women.

“Whether she’s on the inside or the outside, Elizabeth Warren is going to say and do what Elizabeth Warren thinks is the right thing to say or do, and that’s a virtue,” said Axelrod. “But it isn’t necessarily a virtue if you’re trying to script a campaign or an administration.”

Figuring out how best to work with Warren has bedeviled the Obama administration for seven years, as the president has tried to seize the passion she inspires among liberals while contending with her demands that he take a harder line against Wall Street.

If Clinton wins the presidency with help from Warren and her supporters, the pressure on her own administration will only grow.

Warren served in the Obama administration and has generally been an ally, but the association has been punctuated by moments of tension.

She was known to clash over Wall Street regulation with former Treasury Secretary Timothy Geithner. He called their relationship “complicated” in his 2014 memoir. (Geithner and several people who worked with him in the administration did not respond to interview requests.)

In Obama’s first term, Warren’s supporters waged a public campaign on her behalf to lead the consumer protection agency she created in the wake of the financial crisis. Obama, citing Senate opposition, declined in 2011 to nominate her.

Since winning a Senate seat in 2012, Warren brought Congress to the brink of a shutdown because of a provision in a key spending bill that weakened Wall Street regulations. She followed that up by blocking Antonio Weiss, Obama’s choice for a high-ranking post at Treasury, because of his previous work on Wall Street.

“With stuff like that, she hasn’t made a lot of friends in certain corners of the administration,” said Jim Manley, a former aide to Senate Democratic leader Harry Reid.