Welcome to a special, post-debate edition of FiveThirtyEight’s weekly politics chat. The transcript below has been lightly edited.

sarahf (Sarah Frostenson, politics editor): Just seven candidates made the debate stage on Thursday, which means with just weeks to go before the Iowa caucuses, the field is slowly winnowing. And this has left us with a lot of questions — even if Thursday’s debate didn’t move the needle that much. For instance, is it really just a four-candidate race between Joe Biden, Bernie Sanders, Elizabeth Warren and Pete Buttigieg? Or did someone like Klobuchar have a break out performance?

What surprised you the most?

geoffrey.skelley (Geoffrey Skelley, elections analyst): I guess in terms of surprises, it’s that Biden and Sanders didn’t really take much heat in the debate. They had one head-to-head encounter over health care that was notable, with Sanders defending Medicare for All and Biden attacking it for costing too much, but many of the other candidates spent all their time targeting Buttigieg instead.

Buttigieg is narrowly ahead in Iowa, so that probably influenced Klobuchar and Warren’s attempts to go after him. But it’s somewhat remarkable to see the guys with the top polling numbers nationally mostly avoid criticism from other candidates on the stage.

seth.masket (Seth Masket, political science professor at the University of Denver and FiveThirtyEight contributor): What surprised me the most was how different a 7-person stage is from a 10-person stage. The conversations were substantive and useful. I regretted the loss of some earlier voices, but the dialogue last night was impressive overall, as were the criticisms.

geoffrey.skelley: I’ll second that, Seth. It was a richer debate because we heard more from every candidate on stage.

geoffrey.skelley: Considering Iowa is the alpha and omega of Klobuchar’s campaign, her going after Buttigieg as intensely as she did definitely made sense. Warren needs Iowa and New Hampshire, too, so her hits on Buttigieg weren’t a surprise, either, but I am really surprised Biden or Sanders weren’t attacked more.

julia_azari (Julia Azari, political science professor at Marquette University and FiveThirtyEight contributor): I’m struggling to come up with a surprise. Maybe I was perhaps a bit surprised that the moderators mentioned race in the primary as directly as they did, but I also found the difference between the first half and the second a bit jarring. It was pretty collegial until it wasn’t.

Who struggled?

julia_azari: I forgot Biden was there for a while, and Warren’s decision to go after Buttigieg might very well backfire. I do think his criticisms of her wealth and campaign finance decisions illustrated some of the challenges of making populist appeals, though, and that could cut against what seems to be the main justification for her candidacy — her credibility and authenticity on economic issues.

seth.masket: I don’t think Buttigieg had a bad night, necessarily, but he did take a lot of heat. He largely had good retorts, I thought, but his surge may have already run its course and he clearly has some vulnerabilities.

geoffrey.skelley: The main question I have about Buttigieg is how the attacks will be received. And I just don’t know — we’ve seen attacks on Biden work to some extent (Kamala Harris) but also fail (Julián Castro).

sarahf: Yeah, I’m not sure what people will make of Buttigieg’s performance. He got high marks, for instance, after the last debate in our poll with Ipsos, but I wonder if he’ll get high marks this time around. Parrying attacks can be a tricky business, because as Geoff pointed out, it’s not always clear how they’ll land. I think all the #winecave business, regarding Buttigieg’s boozy and expensive fundraiser could backfire, for instance.

geoffrey.skelley: I’ve heard it’s trending on Twitter!

sarahf: 😂

julia_azari: Yeah, political science twitter has been pretty vicious about Buttigieg. But I think it’s likely that he’ll benefit from having been attacked, at least in the media reports if not directly in polls.

Who had a good night?

seth.masket: Biden was good! He acted like a front-runner, mainly sticking to his strengths and areas of comfort, and I think he prioritized not screwing up over making big gains. His answer to the question about working with Republicans was very strong, especially given the impeachment events of this week.

julia_azari: Every time there’s a debate I feel like there’s wide consensus that Klobuchar had a good night, and maybe also that Yang had sort of a good night, so I guess I’m of that mind again.

seth.masket: Klobuchar definitely had some very well-executed moments. Her praise of colleagues’ lawmaking work on congressional committees was a backhanded way of criticizing Buttigieg’s relative inexperience, and it was some high-level shade.

sarahf: I’m curious if any of this will move the needle in the polls, though. To Julia’s point we seem to keep having this conversation around Klobuchar (and Booker when he was on the stage) about her having a strong debate performance — and Klobuchar has gotten relatively high marks in our polling with Ipsos, it has just never seemed to translate to a bump for her nationally. It’s hard for me to imagine it’s any different this time, especially given Biden had such a strong night.

geoffrey.skelley: If I had to pick the best nights on pure performance, I would go with Klobuchar and Sanders. I thought Klobuchar was strong on substance but also made a solid electability case by comparing her track record of winning statewide in Minnesota with Buttigieg’s lack of statewide electoral success: “If you had won in Indiana, that would be one thing. You tried, and you lost by 20 points.”

And Sanders also seemed really at ease, even more so than usual. He was passionate, of course, but also was quick on his feet. While most people may remember Buttigieg and Warren battling it out over #winecave, Sanders inserted himself into the fray by saying that Biden and Buttigieg were in a competition to see who could get the most billionaire donors, and that Buttigieg may be trailing Biden 44 billionaires to 39, but that Buttigieg is “an energetic guy, and a competitive guy” who could “take on Joe on that issue.” It was an attack punctuated with some humor, too.

Did you learn anything new?

seth.masket: Sanders is white?

geoffrey.skelley: South Bend has a river running through it?

seth.masket: But to be serious for a moment, on the identity claims, I was somewhat surprised to see Sanders say he was Jewish, as he hasn’t talked much about being a Jewish American, and Buttigieg to describe himself as a “gay dude in Mike Pence’s Indiana.” Political types know these things, but are they generally known in the population? I’m not sure.

sarahf: Hearing candidates stake out positions on USMCA, the new trade agreement among the U.S., Canada and Mexico that passed the House earlier this week in a bipartisan vote, was notable. It gave me a new lens to think through how some of the candidates would approach bipartisan legislation. Sanders was adamantly against it, arguing that he wouldn’t vote in favor of it because it wouldn’t prevent “outsourcing” or do enough to protect workers, while Klobuchar was in favor of the deal.

julia_azari: I mean, is it remarkable that there was an impeachment vote yesterday and it affected the debate … not at all?

geoffrey.skelley: I guess that speaks to how partisan the impeachment has been. Everyone on stage favored impeaching the president, so it wasn’t really an area to find notable disagreements. If Gabbard had made the stage, though, her “present” vote on both articles might have been fodder for debate.

seth.masket:I wonder if anyone will ask the candidates, “What if your opponent isn’t Donald Trump?” I mean, the odds of that happening are pretty low, but maybe it’s worth discussing?

How did the moderators do?

julia_azari: I thought they were pretty substantive at times, but the race question (why is there only one candidate of color on stage) addressed to Andrew Yang was a sour note, fulfilling stereotypes that non-white candidates bear the primary responsibility for addressing diversity issues.

seth.masket: Given the absence of several candidates of color, the moderators did a good job keeping the conversation focused on race within several issues. But yes, I agree with Julia.

geoffrey.skelley: From a substance standpoint, I thought they did well. There was more foreign policy in this debate — PBS gonna PBS — which is really something we should spend more time on given how much power presidents have in that arena. At the same time, it’s also 💤 territory for many viewers.

julia_azari: They also asked about climate change relatively early on, which is an issue that has been absent from other debates and something that people have complained about.

geoffrey.skelley: That question at the end about gifts and forgiveness was silly, though.

julia_azari: Oh yes. Agreed, Geoffrey. Those closing questions can be so silly.

seth.masket: Yeah, that was a dumb question at the end, but as Renee Ann Cramer noted on Twitter, the answers were fascinating: Basically all the men wanted to gift their books and wisdom, while the women asked forgiveness.

Does the debate change anything in the horse race?

seth.masket: If Buttigieg has peaked (I think the polling trend is hard to discern at this point), I could imagine a Klobuchar surge. But as you all noted earlier, that hasn’t happened yet.

geoffrey.skelley: Depending on how those attacks against Buttigieg land, maybe this debate moves the needle in Iowa.

Remember that plenty of voters still haven’t made up their minds. A national CNN poll released on Thursday found that just 39 percent of Democrats had “definitely” decided on who they’re supporting. And as we get closer to the actual contests, more people will be paying attention, including last night — people could have been tuning in for the very first time. However, I expect the debate in January, when Iowa is right around the corner, will matter more in shifting opinions than last night’s.

julia_azari: The debate might refocus coverage on Buttigieg and give rise to some specific Buttigieg vs. Klobuchar moments or Buttigieg vs. Warren exchanges, which I think opens up a different vein than the Warren/Bernie vs. Biden thing that’s sort of defined the field thus far.

Biden’s closing statement was telling in that he said that everyone on the stage had “big progressive plans.” It seemed to me in this debate that the overall tone of the conversation had shifted left. Some candidates are still making the case for more moderate positions, but I think it’s clear that the left has set the terms of debate.