Elizabeth Warren usually pushes back on the idea of political lanes, but with a narrowing field on the eve of Super Tuesday, she was making the case that she's the compromise candidate in the Democratic Party.

"We find ourselves barreling toward another primary along the same lanes as 2016: one for an insider, one for an outsider," she said Monday night in Monterey Park, California. "Democratic voters should have more choice than that."

The Massachusetts senator made a reference to the endorsements Biden received Tuesday, though she didn't identify the former opponents who announced their support of him earlier that evening, Pete Buttigieg, Amy Klobuchar and Beto O'Rourke.

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"No matter how many Washington insiders tell you to support him, nominating their fellow Washington insider will not meet this moment," she argued. "Nominating a man who says we do not need any fundamental change in this country will not meet this moment."

In an interview with CNN's Don Lemon Monday, Warren said of her former opponents' endorsement of Biden, "I think that they see the world in many ways the same way that the vice president does. So I understand that. I think it makes some sense."

Noting that "the field has now narrowed sharply," with the moderates aligned on one side, Warren argued that their policies are not the ones the country wants.

"I think that what we've seen so far is that the Democratic Party is a progressive party," she told Lemon. "Progressive ideas are popular."

Bernie Sanders, who is the front-runner, has been the standard bearer for progressive policies like Medicare for All and free college. Without naming him, Warren raised doubts about his ability to enact these initiatives and sought to argue that she can, that she is the clear candidate for Americans who want a progressive agenda that can actually be enacted.

"We need someone who's going to get those progressive ideas done," she said. "And that's the reason I'm in this race."

She also criticized Sanders for his approach to paying for Medicare for All, estimated to cost around $30 trillion.

"Bernie thinks that we should raise taxes on middle-class families to pay for health care. And I've shown that we don't actually have to do that," she said. "I think a much better way to do it is to raise taxes on the top one percent, to make giant corporations, like Amazon and Eli Lilly, that report billions of dollars in profits and pay nothing in taxes."

During the Monterey Park rally, Warren again raised questions about how effective Bernie Sanders would be as president, though she did not name him.

"It's not enough to have big ideas. It takes a plan to turn those ideas into reality," she said.

"We need a nominee who has unshakeable values and who has a real track record for winning hard fights," Warren said of her candidacy. Sanders' supporters often accuse Warren of not having "unshakable values."

Just after Warren appeared on stage, three topless animal rights protesters stormed the stage and were escorted away by police. "I love Los Angeles," Warren said, before launching into a speech about the power of protest.