Trendlines in the RealClearPolitics average of polls show Elizabeth Warren on a continuous rise since the September debate at the expense of almost everyone else in the field. This surge has brought about more media coverage, but also increasing scrutiny coming from the remaining candidates. The night largely ended up as a vetting of Warren, which she mostly passed, but not without a few contentious moments. Each candidate’s grade reflects the extent to which their performance on the night is likely to help their chances in the primary.

Elizabeth Warren: A-

Senator Warren came into the debate with high expectations for a second time running, as well as more attention being paid to her surging candidacy. Judging by her amount of speaking time alone — six minutes more than Joe Biden, who was second in speaking time — one might easily be convinced that she is the de facto leader in the race. She had to handle attacks from multiple sides, often doing quite well. The most notable critiques came from Buttigieg, Klobuchar and Biden, usually calling her plans some version of “pie in the sky.” If for no other reason than the amount of attention being paid to her and attacks by the candidates at her side, she came across as the one to beat in the room. Overall, much of the debate seemed like an attempt by several candidates to discredit Warren, with her passing the test, despite a few attacks from Klobuchar and Buttigieg having some bite to them. It will be interesting to see if the polls reflect this.

Bernie Sanders: B+

Perhaps no candidate had more riding on this debate than Senator Sanders, who came into it on the heels of a heart attack a couple of weeks prior and a media narrative that suggests his campaign is headed nowhere. Given the questions around his health and the viability of his candidacy, he could hardly have hoped for a better night. Sanders may well be the only candidate that can be said to focus on policy and big ideas to a fault. Considering the debate format and how much value notable one-liners carry, policy alone has hardly ever made any candidate a winner of a debate, let alone a primary. When moderator Erin Burnett was getting ready to ask about his health and how he plans to reassure voters that he is up to the stress of the job, he tried to interject to get a point across on the discussion about holding pharmaceutical executives accountable for disasters such as the opioid epidemic. He did answer immediately after, inviting all to attend or watch a major rally in Queens with a special guest — which was later reported to be Congresswoman Alexandria Ocasio-Cortez, perhaps one of the most sought after endorsements of the primary — and suggesting that the vigorous campaign that he hopes to wage should assuage such concerns. The solid performance, coupled with endorsements from Congresswomen Ilhan Omar and Ocasio-Cortez should reinvigorate the Sanders campaign and give it good PR for the time being, enough to make him one of the winners of the night.

Amy Klobuchar: B

Senator Klobuchar had her best night of the campaign thus far. She came ready with pointed critiques, specifically on healthcare, for Senator Warren. Warren’s performance could stand to suffer depending on whether or not those arguments, which can be watched in full here, landed for voters. She had a strong night, with firm responses and material ready to go on the offensive with at a moment’s notice. Klobuchar and her staff hope this will be an inflection point in the race for her, but if one thing is for certain, it is far more difficult to make a lasting impression — specifically when it is needed for a campaign that is struggling — on a 12 candidate stage than, say, a five or six candidate field.

Joe Biden: B-

Senator Joe Biden's performance was a mixed bag. On the one hand, it seems that the consensus that he is the one to beat has shifted, and because of this, he joined almost everyone else, sans Sanders, in going after Warren and her ostensible lack of transparency and clarity in her plans. His response to the claims of misdeeds by him and his son in relation to Ukraine drummed up by the White House was unconvincing at best. He did, however, have some effective lines, particularly on foreign policy, where he exuded confidence, competence and experience. Referencing his experiences in dealing with foreign leaders, Biden called Trump's recent decision to remove troops from northeastern Syria shameful and an abandonment of the Kurds in favor of Erdoğan. He also had a moment with Warren that some perceived as Biden shouting her down and trying to take credit for the Consumer Financial Protection Bureau, which was created in large part thanks to Warren’s efforts. Warren seemed startled, and it made for a very awkward moment, which will surely not help him. It was a decent display overall from Biden, but nothing that will make him more likely to win the nomination than last week.

Pete Buttigieg: B-

Mayor Buttigieg, who enjoyed a wave of great press and overall attention paid to his campaign when he finished Q2 as the top fundraiser in the field, has struggled to take a further step forward since. He may have enjoyed his best debate thus far, although there were a few strange moments as well. His aforementioned questioning of Warren on healthcare was strong, and there is evidence to suggest that Klobuchar and Buttigieg did well for themselves on this subject. He also harshly rebuked Beto O'Rourke during a back and forth on the issue of guns when O’Rourke hinted that Buttigieg’s opposition to his proposal was because he is being controlled by poll testing and political consultants, to which Buttigieg responded that he does not need lessons from O’Rourke about courage, political or personal. This came across as harsh and unnecessarily derisive. Nonetheless, the potential for growth may well be there for Buttigieg — although it would have to come at the expense of somebody else, like Biden or Warren falling substantially — and will largely come down to who the voters trust more on healthcare, a choice between candidates behind Medicare For All and those in support of a reformed Affordable Care Act like Buttigieg. This seems to be the wedge issue that his campaign has decided is most important to press on, and it has some pundits declaring the Mayor of South Bend one of the winners of the night.

Cory Booker: B-

Senator Booker set a fundraising goal shortly after the third debate, suggesting that if he was unable to reach it he would have to drop out. He reached the goal, and continues on for the time being. There is, unfortunately, not an awful lot to say about Booker or his performances. He was pretty good, as he was at most of the debates thus far, but seems to have fallen short of making an impactful positive impression, or, more importantly, gaining support, and that is unlikely to change from this performance.

Andrew Yang: B-

Businessman Yang had a decent night as well, scoring a few good points for himself on contrasts in policy with other candidates. The most noteworthy back and forth for Yang was probably when he squared off with Bernie Sanders and Elizabeth Warren. He said that Sanders’ federal jobs guarantee is looking to the past for solutions to present or future problems, because most Americans do not want to work for the government. Then he got a word in about Warren’s quip that blaming job loss on automation is “a good story, except it’s not really true” by responding that Americans are smart and can see what is happening around them, and that UBI is the best solution to these problems. Once again, how well these exchanges went for their respective contributors depends on who the viewers find more trustworthy on the issue. 

Kamala Harris: C+

Senator Harris and her campaign seem to have lost the plot, at least for the time being, and are thus struggling to find a way back into the “top-tier” of candidates. It’s interesting because her first debate performance was quite emphatic and drew a lot of attention — mostly positive from what I saw, but some negative as well — which was supposed to cement her status among the leaders in the race. Her poll numbers did initially go up, and according to RCP averages, they nearly doubled shortly after the June debates, but it seems that her campaign has decided against that more assertive and unapologetic posture, which raises the question as to why. The back and forth with Warren about banning Trump from Twitter seemed like an odd topic to put so much emphasis on, but she did have a strong moment in her impassioned defense of women’s reproductive rights. Her languishing campaign definitely needs a jolt of energy, but it was nowhere to be found that night.