Sen. Elizabeth Warren (D-Mass.) has been playing nice. She has emphasized unity instead of attacking other Democratic presidential candidates. She has stuck to her campaign themes instead of criticizing opponents. And she has been sliding steadily downward in the polls for the 2020 Democratic nomination.

That changed Wednesday night at the Democratic debate.

“I’d like to talk about who we’re running against: a billionaire who calls women ’fat broads’ and ‘horse-faced lesbians,’” Warren said in her opening comments. “And, no, I’m not talking about Donald Trump. I’m talking about Mayor Bloomberg.”

Again and again on Wednesday night, Warren humiliated former New York City Mayor Michael Bloomberg ― not only by presenting him with his own words but also by pressing him to release an unknown number of women who worked for him from nondisclosure agreements pertaining to sexual harassment. Bloomberg refused.

But Bloomberg wasn’t the only source of her ire. In less than a minute, she pummeled three other opponents ― former South Bend, Indiana, Mayor Pete Buttigieg, Sen. Amy Klobuchar (Minn.) and Sen. Bernie Sanders (I-Vt.) ― on health care.

“Mayor Buttigieg really has a slogan that was thought up by his consultants to paper over a thin version of a plan that would leave millions of people unable to afford their health care. It’s not a plan, it’s a PowerPoint,” she said. “And Amy’s plan is even less ― it’s like a Post-It Note: ‘Insert plan here.’ Bernie ... has a good start. But instead of expanding and bringing in more people to help, instead his campaign relentlessly attacks everyone who asks a question or tries to fill in details about how to actually make this work.”

This is the Warren who made Wall Street executives wilt at Senate hearings and became a feminist icon on the left for refusing to stop speaking when Senate Majority Leader Mitch McConnell (R-Ky.) tried to silence her.

It’s the Elizabeth Warren who infuriated President Barack Obama by attacking his trade agenda and assailing his budget deals with Republican leaders.

It’s the Elizabeth Warren who promised to leave “plenty of blood and teeth on the floor” fighting for a tough Wall Street reform bill.

Susan Walsh/Associated Press In 2016, Senate Banking Committee member Elizabeth Warren (D-Mass.) questioned Wells Fargo CEO John Stumpf during a hearing on bank employees opening millions of unauthorized accounts to meet sales targets.

On Wednesday night, Elizabeth Warren sounded like the Elizabeth Warren who Washington insiders have come to fear over the past dozen years. But it was an Elizabeth Warren who has been all but invisible over the course of her 2020 campaign. And it might be too late to save her deliberately milquetoast run for president.

Warren’s preference for a fight has been consistently downplayed throughout the campaign, and completely absent from her performance in recent months.

With rare exceptions, she has declined to criticize the other candidates, sticking to an “I’m not here to attack other Democrats” mantra. And since the new year, her campaign has played her up as a “unity candidate” ready to bring the warring wings of the Democratic Party together, rather than highlighting their differences.

This strategy peaked in New Hampshire, where Warren finished a disappointing fourth and failed to net any delegates. During a debate before the primary in Manchester, she barely mixed it up with the other candidates. Her speech, delivered early in the night, consisted primarily of asking the other candidates to stop fighting.

“These harsh tactics might work if you’re willing to burn down the rest of the party in order to be the last man standing,” she said at the time. “They might work if you don’t worry about leaving our party and our politics worse off than how you found it. They might work if you think only you have all the answers and only you are the solution to all our problems.”

But Warren has never been subtle during her career in Washington. She speaks loudly and carries a big stick ― frequently against her own party. She was Obama’s chief antagonist over the Trans-Pacific Partnership, a trade deal that ultimately failed due to opposition from progressive Democrats and a sizable block of House Republicans.

At the close of 2014, she led a congressional insurgency that nearly shut down the federal government in an effort to block a deal between Obama’s administration and congressional Republicans to deregulate risky Wall Street trading.

She earned the ire of many of her fellow Democrats by calling out their support of Trump’s effort to eliminate protections against racial discrimination in mortgage lending.

Tonight, Elizabeth Warren showed us why she makes billionaires literally cry. Nelini Stamp, Working Families Party

But on Wednesday night, Warren seemed back to her old self, as her staffers tweeted “BLOOD AND TEETH” ― a reference to something she said in an interview with HuffPost in 2010, when she was battling to create the Consumer Financial Protection Bureau. While she spoke far less than the other major candidates during the New Hampshire debate, she led the field in speaking time on Wednesday night.

Warren’s fan base responded. She raised more money during the first hour of the debate than she had in any previous hour of the campaign, and she raised $2.8 million over the course of the day Wednesday. (She narrowly edged Sanders, who raised $2.7 million.)

“Tonight, Elizabeth Warren showed us why she makes billionaires literally cry. She’s smart, she’s a fighter and she’s the single best person to take on Donald Trump on the debate stage,” said Nelini Stamp, director of strategy and partnerships at the Working Families Party, which has endorsed Warren.

Rep. Andy Levin (D-Mich.), a Warren supporter, made it clear her attacks on Bloomberg were meant as a preview of how she would battle a different superrich New York businessman with a history of derogatory comments about women.

“She stood right next to Michael Bloomberg and she took him down,” he said in the spin room after the debate. “And Michael Bloomberg has a lot in common with Donald Trump.”

That fighting spirit is what draws many of her supporters to her.

“She’s always been so passionate. ... People might say she’s angry. But I think she has a point she wants to make. And that’s the way to make it,” said June Blankin, 55, a Warren supporter from Falls Church, Virginia, who attended the senator’s town hall event in Arlington last week.

“She’s a fighter,” added her husband, Duane Ludwig, 47.

But this performance may come too late. Sanders has largely consolidated the most liberal primary voters and young people, and remains the clear front-runner for the nomination. Early voting in Nevada is already done, and more than 500,000 people have already voted in delegate-rich California. More than one-third of the delegates will be awarded in less than 13 days.

Warren’s polling has been steadily dropping for months, and the crowded field may prevent her from reaching the 15% viability threshold necessary to earn delegates in key states.

Jeff Weaver, a top adviser to Sanders, didn’t seem worried about facing a revitalized Warren, noting the Vermont senator had triumphed in both Iowa, where Warren outperformed her polling, and in New Hampshire, where she slipped into fourth place.

“In places where she’s done well, we’ve won,” Weaver said. “In places where she hasn’t done well, we’ve won. So we just play our own game.”

The Warren campaign is known for saying it doesn’t ride the so-called poller-coaster. But it may have allowed too long a drop.