Sen. Bernie Sanders (I-Vt.), fresh from a victory in New Hampshire and rising in national polls, knew he would be a target at the debate Wednesday night as he faced off against former vice president Joe Biden, who’s been tumbling in the polls; former New York mayor Mike Bloomberg; Sens. Amy Klobuchar (D-Minn.) and Elizabeth Warren (D-Mass.); and former South Bend, Ind., mayor Pete Buttigieg, who was coming off a close second in New Hampshire but is struggling to win over nonwhite voters.

To date, Sanders’s opponents have spent a good deal time scuffling among themselves, challenging Sanders mostly on Medicare-for-all. That dynamic changed dramatically during Wednesday’s debate, making for the most exciting debate of the primary season.

Buttigieg most fiercely went after Sanders, taking shots at the senator’s health-care plan, his refusal to release his health records and his “my way or the highway” policy stances. Standing among several older guys yelling at one another, Buttigieg came across as exceedingly calm. On climate change, he offered a sense of urgency and promised to add farmers to the solution. Unlike Sanders and Warren, who are ready to put workers in old energy sectors out of business, he argued the best way to help those displaced is to offer more jobs. He rebuffed Bloomberg’s suggestion we could convince China to see things our way on climate change. He repeatedly tussled with Klobuchar, lighting into her for voting to confirm Trump appointees. When she accused him of not being in the arena (“you’ve memorized a bunch of talking points”), Buttigieg shot back: “This is the arena, too. You don’t have to be in Washington to matter.”

Sanders, pummeled during the day for his refusal to produce once-promised medical records and his spokeswoman’s false accusation that Bloomberg had suffered heart attacks, needed to show he had responses to legitimate concerns about his health. He didn’t. He simply reiterated that he had put out letters, not his complete health record. He yelled through much of the debate, insisting his Medicare-for-all proposal would not force Nevada’s Culinary Union (which opposes Sanders’s proposal) to give up its health-care plan. He also went full-on socialist, telling Bloomberg he shouldn’t have been allowed to earn his billions.

Bloomberg made clear coming into the debate that he wants this to be a two-person race between him and Sanders. It turned out to be a free-for-all, with Bloomberg as the target — primarily concerning his stop-and-frisk policy as mayor but also on his use of nondisclosure agreements with former employees at his news and business information company. On stop-and-frisk, he tried to get out of trouble by saying the problem with the policy was how it “turned out.” Warren shot that down, noting that it was wrong from the onset. Warren also laid into him on nondisclosure agreements, demanding he say how many NDAs existed. Biden also jumped in, challenging Bloomberg to release ex-employees from the NDAs. It was a surprisingly awful exchange for Bloomberg, who must have known the hit was coming.

For Biden, it is essential he show some improvement in Nevada (even a third-place finish would be a lift). If not, his campaign may implode before Super Tuesday. He arrived at the debate with the game plan to attack both Bloomberg and Sanders. He largely delivered, hitting Bloomberg on stop-and-frisk (reminding the audience it was the Obama administration that came in to New York City to monitor the tactic and then called for its end), and Sanders on his health-care plan. He inserted himself into a squabble between Klobuchar and Buttigieg on Mexico policy, asserting his experience with the country. He made a strong showing on climate change. He also challenged Bloomberg, saying “greed" — and not the end of redlining — was responsible for the financial crash. On socialism, he neatly sidestepped the argument over labels and went back to his basic message of economic fairness and equalizing the tax on capital gains and wages. He hit back at Warren for suggesting he wanted to be the friend of Senate Majority Leader Mitch McConnell (R-Ky.) and showed off his empathy for ordinary working-class people.

Klobuchar and Warren, both struggling to stay in the race, needed a big boost to boost their poll numbers and infuse their campaigns with cash. Warren tried to lift her profile by hitting everyone on the stage — except Sanders — for just about everything. She might have helped deflate Bloomberg, but refusing to go after the candidate cleaning her clock with progressive voters may not work to her advantage. At times, she seemed churlish, accusing moderates of wanting to be “liked” by McConnell.

Klobuchar had her moments, hitting the progressives for not understanding that Democrats had to win outside blue enclaves. She wound up in a spat with Buttigieg over her failure to name the president of Mexico. Unlike recent debates, she seemed to be caught back on her heels; her obvious personal dislike for Buttigieg did not make her seem like the uniter she has promised to be.

WINNERS: A fiery debate with minimal moderator-intrusion; Buttigieg; Biden

LOSERS: Bloomberg; Warren’s refusal to hit Sanders; Klobuchar’s spats with Buttigieg

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