WESTERVILLE, Ohio — The CNN/New York Times debate on Tuesday night revealed new dynamics in the Democratic presidential race: Senator Elizabeth Warren took sustained fire from multiple rivals, former Vice President Joseph R. Biden Jr. struggled to make an impact and Mayor Pete Buttigieg and other candidates were newly aggressive in making their points.
Here are six takeaways from the debate:
Warren takes incoming, for a change
For the first time this year, Ms. Warren was frequently called out and criticized by her rivals:
Mr. Biden called her health care plans “vague” and argued she had never accomplished anything big.
Mr. Buttigieg implied she didn’t trust the American people to decide whether they wanted to remain on private health insurance plans.
Senator Amy Klobuchar denounced Ms. Warren’s plans as a “pipe dream.”
Senator Kamala Harris wanted to know why Ms. Warren didn’t join her call for Twitter to ban President Trump from its social media platform.
For a candidate who has risen in the polls based on her policy acumen and specifics, Ms. Warren’s unwillingness to address the question of whether her “Medicare for all” plan would require higher taxes on the middle class was striking. And her opponents put her on the defensive.
Ms. Warren in large part survived the attacks, though she never did answer questions about whether she’d raise those middle-class taxes. Nor did she explain to Ms. Harris why she thinks Mr. Trump should remain on Twitter. But she did present a concise counterargument, saying that only her ambitious ideas can produce an electoral mandate from disaffected Americans to defeat Mr. Trump.
In all, the debate served as a certification of Ms. Warren’s status as one of two front-runners in the race, alongside Mr. Biden. It also crystallized much of the 19-way race as a contest to be the Biden alternative. The candidates sparring with Ms. Warren were auditioning to Democratic voters not just how they would go toe-to-toe with President Trump, but also how they would stack up against Ms. Warren as the campaign narrows to just a few candidates.
Unlike the previous three debates, nobody instigated a fight with Mr. Biden. It was a sign both of his diminished status in the race — he’s no longer the solo front-runner, having ceded ground to Ms. Warren — but also evidence that attacking Mr. Biden hasn’t served his rivals well when they’ve tried.
The toughest moment for Mr. Biden came when the moderators pressed him on his son Hunter Biden’s work in Ukraine. When no candidate pressed him on the topic, it faded from the discussion after Mr. Biden delivered a garbled and wobbly explanation.
Mr. Biden, as is his custom, at times wandered away from the question at hand. During a monologue about tax rates, he bemoaned the size of the field and the relatively brief amount of time allotted candidates to answer questions.
He was strongest when on offense against Ms. Warren. But it was a telling sign that his rivals tried to present themselves as a Biden alternative by contrasting themselves with Ms. Warren instead of Mr. Biden. She. not the former vice president, looked like the candidate to beat on Tuesday night.
Sanders calms concerns post heart attack
He railed against billionaires. He pitched “Medicare for all.” He tossed out his campaign URL. He said “damn” — twice.
It was vintage Bernie Sanders on Tuesday — and that was a relief to his supporter and advisers two weeks after the 78-year-old suffered a heart attack.
“I’m healthy, I’m feeling great,” Mr. Sanders said as the debate approached the two-hour mark. But by then Mr. Sanders had made that case with his performance, dueling with Mr. Biden over their ideological differences and thrusting his arm into the arm to seek more airtime.
“We are going to be mounting a vigorous campaign all over this country. That is how I think I can reassure the American people,” Mr. Sanders said when asked about his health.
When Senator Cory Booker interjected with a joke that Mr. Sanders also supports medical marijuana, Mr. Sanders did not hesitate with the retort, “I’m not on it tonight.”
He may not have won over new supporters, but he looked like the same old Bernie Sanders. For this debate, that was more than enough.
Buttigieg’s biggest night yet
For months, Mr. Buttigieg has been satisfied to make most of his points at the debates without scoring them at the expense of his rivals. That ended Tuesday.
Mr. Buttigieg sparred sharply with former Representative Beto O’Rourke on guns. He rebuked Representative Tulsi Gabbard on foreign policy. And, most notably, he engaged in the most substantive and sustained contrast of any candidate yet with Ms. Warren.
It was Mr. Buttigieg’s exchange with Ms. Warren over “Medicare for all” that was most memorable, pressing her as she declined to say, yet again, whether her plan would require a middle-class tax increase. (She says her plan would curb middle-class “costs.”)
“A yes or no question that did not get a yes or no answer,” Mr. Buttigieg said, adding, “Your signature, Senator, is to have a plan for everything. Except this.” He rattled off how her plan would “obliterate” the private health insurance of 150 million Americans while pitching his “Medicare for all who want it” alternative.
Mr. Buttigieg’s rebuke of Mr. O’Rourke — “I don’t need lessons from you on courage” — may lend itself more to a viral moment. But the bigger leap was to be seen as a foil to Ms. Warren.
It felt at times on Tuesday as if the sprawling 12-person stage had actually narrowed to a four-person debate, with Ms. Warren and Mr. Sanders representing the left, and Mr. Biden and Mr. Buttigieg representing the center-left. The occasional television shot of just those four served to hammer home the point.
Booker and Harris settle for staying out of fray
Mr. Booker and Ms. Harris were not the main course on Tuesday. They were the palette cleansers. Mr. Booker and Ms. Harris both came into the debate struggling for support and attention. And it was apparent by the end of the first hour that they had adopted a similar game plan: seeking to rise about the fray and food fight unfolding around them while punching at President Trump.
“Tearing each other down because we have a different plan is unacceptable,” Mr. Booker said. He had been the first candidate to castigate the media for asking Mr. Biden questions about his son’s work in Ukraine.
At one point, Ms. Harris aired a complaint that women’s advocates have pressed for months: the lack of questions about abortion. “This is the sixth debate we have had in this presidential cycle. Not one word with all of these discussions about health care, on women’s access to health care. It’s outrageous,” Ms. Harris said.
On Tuesday, both Ms. Harris and Mr. Booker hit Mr. Trump harder on foreign affairs than any rivals onstage. This is not a new strategy. Ms. Harris focused on Mr. Trump during the last debate, too. And for two candidates who have punched their ticket to November, this was a bloodless way to sell themselves without much risk on a crowded stage.
No game-changing moments for low-polling candidates
The sixth night of Democratic presidential debates delivered three hours of discussion but no signature moments and little likely to be remembered when the primaries and caucuses begin in February.
The most contentious exchanges — between Ms. Warren and Mr. Buttigieg, and then again between Mr. Biden and Ms. Warren — were intermittent, spaced throughout a debate that by obligation had to include seven candidates who haven’t sniffed 5 percent in a poll in months.
With so many low-polling candidates obligated to get speaking time too, the debate meandered through exchanges with Ms. Klobuchar, Mr. O’Rourke and Mr. Castro, each of whom faces long odds to appear at the party’s next debate on Nov. 20 in Atlanta. The billionaire investor Tom Steyer was there too, though, in his first debate appearance, spent more time introducing himself to Democratic voters than he did making a case why he’d be better than anyone else onstage.
While exposing the divisions between the party’s factions, the most taut moments of contrast served more as an example of what is to come once the field shrinks.