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Everyone came to Vegas to fight—everyone, that is, except Michael Bloomberg.

Tonight’s debate at the Paris Theater on the Las Vegas strip was the feistiest free-for-all of a marathon campaign that saw its first votes cast only two weeks ago. The candidates went after one another with abandon—front-runners filleting the underdogs, zingers crisscrossing the stage like lasers. A newly energized and combative Senator Elizabeth Warren of Massachusetts tried to reassert herself in the race by taking down just about all of her five competitors—but particularly the former New York mayor.

Bloomberg made his debate debut after entering the race 10 weeks ago, and his lack of experience on the national stage was apparent from the evening’s opening moments. Bloomberg, who has muscled his way into the top tier on the back of nearly a quarter billion dollars in advertising, came under withering criticism from his rivals on a broad range of issues. Again and again, he struggled to respond. Warren and former Vice President Joe Biden assailed the stop-and-frisk policing policy Bloomberg presided over as mayor, which he defended for years despite data that showed it disproportionately affected young men of color. Senator Bernie Sanders of Vermont knocked him for his Republican past, noting his endorsement of President George W. Bush in 2004 and the financial support he has given to GOP candidates in the many years since.

No one, however, attacked Bloomberg harder, or with more gusto, than Warren. She began the debate by reminding voters of the “billionaire who calls women fat broads and horse-faced lesbians.”

“No, I’m not talking about Donald Trump. I’m talking about Mayor Bloomberg,” she said. “Look, I’ll support whoever the Democratic nominee is, but understand this. Democrats take a huge risk if we just substitute one arrogant billionaire for another.”

Later in the debate, Warren directly confronted Bloomberg about the allegations of workplace harassment at his eponymous financial company. With help from Biden, she tried to force him to release women from the nondisclosure agreements they had signed. After Bloomberg countered that he had hired and promoted women both at his company and at city hall, Warren summarized his defense as “I’ve been nice to some women.”

And after Bloomberg repeated the apology he had issued for stop-and-frisk, saying that New York City police officers had “stopped too many people,” Warren replied, “You need a different apology, Mr. Mayor.”

The closest thing to a national debate Bloomberg has taken part in happened during the last race he ran for mayor—more than a decade ago. Tonight, the 78-year-old viewers saw on TV was a far cry from the one in the well-produced ads that have flooded the airwaves across the country and catapulted him into second place behind Sanders in some national polls. He seemed irritated at the attacks, asked the moderators for more time to respond, and snapped at Biden, “Let me finish, please.”

Viewers also saw a very different Warren from the candidate that largely eschewed attacks on her opponents for the campaign’s first year. Fighting both a cold and the irrelevancy of the second tier, she went after not only Bloomberg but Senator Amy Klobuchar of Minnesota and former Mayor Pete Buttigieg as well. “It’s not a plan; it’s a PowerPoint,” Warren said of Buttigieg’s health-care proposal, which she said had been handed to him by consultants. “And Amy’s plan is even less. It’s like a Post-It note: ‘Insert plan here.’” (Warren did later defend Klobuchar, however, after Buttigieg criticized his moderate rival for forgetting the name of the Mexican president.)

Indeed, it was hard to keep track of all the attacks the candidates deployed, making this debate nearly unrecognizable from the often snoozy—but substantive—affairs that preceded it. (Even The Onion noticed the change in tone.)

It wasn’t difficult, though, to find a reason for the shift. The voting has started, and the next contests in Nevada and South Carolina could turn the primary campaign into a two-man race between a 78-year-old billionaire and a 78-year-old democratic socialist, neither of whom was a registered member of the party as of a few years ago. For Warren, Biden, Klobuchar, and Buttigieg, tonight’s debate was perhaps one of their final chances to change the trajectory of the campaign before Super Tuesday.

And so, on a February night in Las Vegas, they collectively decided to show up and fight.

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