Below, who did well and who didn't.
• Joe Biden: I've had him as a loser in just about every debate thus far. He's been halting, often confused and hasn't shown himself to be the kind of debater Democrats will want going toe-to-toe with President Donald Trump. Thursday night was better. It wasn't flawless, but he kept things on the rails, had flashes of good humor, and was deft with tough moments he could see approaching, including about his age.
He dealt particularly well with the toughest question he got, which was about a recent Washington Post report on how leaders, including those in the Obama administration, misled the country about the status of the war in Afghanistan. He said he argued against nation-building there and emphasized disagreements with the Pentagon about things like the troops surge. And he's got documents to back that up. He had previously struggled when asked to own particular elements of the Obama legacy, but not Thursday.
Perhaps most importantly for him, as the candidate who leads almost all of the national polls - and has in recent weeks reasserted that lead - the other candidates mostly gave him a pass. Even when the topic was conducting high-dollar fundraisers, most of the heat was trained on South Bend, Indiana, Mayor Pete Buttigieg, and when Sen. Bernie Sanders of Vermont seemed to want to press the issue on Biden, he was bypassed. Suddenly, we saw the Joe Biden who dealt with Paul Ryan in the 2012 vice presidential debate. Will he stick around, though?
• Buttigieg under fire: The most pointed exchange of the evening - and one of the most pointed exchanges of any debate to date - came when Elizabeth Warren went after Buttigieg. Hard. It was pretty brutal. She pointed to a fundraiser he recently held in a wine cave. "Billionaires in wine caves should not pick the next president of the United States, Mr. Mayor," she said, punctuating it by referring to $900 bottles of wine and addressing him directly.
But Buttigieg, as he almost always has been, was prepared. He noted he was the least wealthy of anyone onstage, and then he hit back just as hard. He noted that Warren transferred millions raised for her Senate campaign to her presidential bid, which included money raised at big-dollar fundraisers. "This is the problem with issuing purity tests you cannot yourself pass," he said. Warren has largely avoided attacking other candidates and has avoided being attacked herself. The fact that she opted to go after Buttigieg reinforces what a force he has become in this race - and how he, even with his more mainstream approach, has apparently peeled off some of her voters.
Buttigieg also parried a series of attempts by Sen. Amy Klobuchar, D-Minn., to goad him, including on his views of press freedom and his comments about the Washington experience of his opponents. It may not have been fun for Buttigieg, but he passed the tests. He's a force in this race.
• A more realistic approach: The early debates were focused on Medicare-for-all, free college and other issues on which the party has moved to the left. But increasingly as the field has shrunk - and Medicare-for-all has fallen out of favor rather quickly with, even Democratic voters - there is more of an emphasis on realism. That's been Buttigieg's angle for a long time, and that was certainly the case again Thursday night. ("We've got to break out of the Washington mind-set that measures the business of an idea by how many trillions of dollars it adds to the budget or the boldness of an idea by how many fellow Americans it can antagonize," was his big line.)
But the rest of the field was there too. Candidates admitted that people might have to be moved from places that are hit by climate change. There was less promising of huge things. Warren didn't play up Medicare-for-all, as she had previously. Bernie Sanders brought it up, and Biden made an impassioned case against its steep costs. Biden also seemed to temper his claim that, if he became president, Republicans would suddenly start working with Democrats. "I didn't say returned to normal," Biden said. "Normal is not enough. In fact, we've had to move beyond normal."
• Bernie Sanders on race, again: If there was one issue that dogged Bernie Sanders in his 2016 campaign against Hillary Clinton, it was his inability to appeal to minority voters. And for one striking moment on Thursday, that problem reared its ugly head again. The candidates were asked about the declining diversity in their debate field, and when the question was presented to Bernie Sanders, he opted instead to try to talk return to a previous topic, climate change. Debate moderator Amna Nawaz of PBS NewsHour cut in, though. "Senator, with all respect, this question is about race. Can you answer the question as it was asked?"
The crowd roared. Sanders tried to rescue it by saying people of color would suffer from climate change, too, and then he offered some boilerplate about problems that plague minority communities. It was one moment, but it came just after the only minority candidate onstage, Andrew Yang, gave a detailed answer citing Martin Luther King Jr., and it briefly revived some old demons.
Sanders also, shortly thereafter, responded to a quote Barack Obama recently gave about old, white men running countries. When debate moderator Tim Alberta noted Sanders was the oldest candidate onstage, and Sanders interjected, "And I'm white, as well!" It wasn't awful, but it may not have been the time to emphasize that.
• Democratic harmony: For the first hour-plus, this looked less like a debate and more like a town hall, in which each candidate was able to use a bunch of talking points, unchallenged. Then things turned. It was Warren vs. Buttigieg, yes, but Klobuchar in particular was looking to mix it up with just about everyone. The candidates took exception to the moderators' questions. Sanders waved his arm when Biden was talking - as he is wont to do - and Biden told him, "Put your hand down for a second, Bernie." Biden even sought to one-up Warren on her selfie game. It was evident that we are about a month and a half from the actual votes.
• The moving background: For some reason, the debate stage featured a moving background with the logos of the debate sponsors. I can't be the only one who found it slightly nauseating?
• The billing: Part of Democrats' challenge in 2020 is to compete with the news machine that is Donald Trump. And that was particularly the case Thursday night, the day after Trump was impeached. It was perhaps an unfortunate bit of timing, including because it was six days before Christmas, and that won't be the case in future. But this was a really substantive debate, and it will be a shame if people weren't tuned in.
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