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What We’re Watching For In The Second Democratic Debate

Welcome to FiveThirtyEight’s weekly politics chat. The transcript below has been lightly edited.

sarahf (Sarah Frostenson, politics editor): It’s hard to believe it’s been a month, but the Democratic primary debates are baaack. And on Tuesday and Wednesday evening, 20 candidates (10 each night) will take the stage, with one potentially big new showdown (Elizabeth Warren vs. Bernie Sanders) on the first night and one big rematch (Kamala Harris vs. Joe Biden) on the second night.

For reference, here’s Tuesday’s lineup: Bernie Sanders, Elizabeth Warren, Pete Buttigieg, Beto O’Rourke, Amy Klobuchar, Marianne Williamson, John Delaney, John Hickenlooper, Tim Ryan, Steve Bullock.

And Wednesday’s: Joe Biden, Kamala Harris, Cory Booker, Andrew Yang, Julián Castro, Tulsi Gabbard, Michael Bennet, Jay Inslee, Kirsten Gillibrand, Bill de Blasio.

So yes, let’s talk about the lineups and matchups, but first let’s also take a step back to talk about the role of primary debates — how do they change the race?

nrakich (Nathaniel Rakich, elections analyst): I think it’s clear that debates can change the race. But the effects might be fleeting, as after one debate the race might move in one direction while subsequent debates might push things in a different direction.

natesilver (Nate Silver, editor in chief): Debates also tend to ramp up in importance as the campaign goes along. It might feel like we’ve been covering this race forever. But we’re still in the rather early stages, as far as voters are concerned.

julia_azari (Julia Azari, political science professor at Marquette University and FiveThirtyEight contributor): I think I might have a slightly different take on this than Nate. My sense, based on the research, is that the debates will produce diminishing returns as opinions become solidified, but that might apply more for minor candidates than for contention between major ones like Harris and Biden. (Though there’s still a notable big name-recognition gap between the two.)

nrakich: I’m with Julia on this one. In 2016, the first Democratic primary debate had the highest ratings.

natesilver: But in some sense, the purpose of these early, very-inclusive debates is to see if any of the minor candidates can break through. Which didn’t really happen after the Miami debates, although you could argue the case for Castro I guess.

sarahf: Castro was interesting. His favorability numbers shot up, but he didn’t really see as much of a swing in support, or at least that is what we found in our poll with Morning Consult.

nrakich: But Castro is a great example of someone for whom the debates could build on each other to increase his support. He got people’s attention in the first debate; maybe, with another good moment this week, he’ll start to get their support. Or at least get enough backing to clear the third-debate thresholds.

natesilver: I’m skeptical that Castro is likely to break through. I mean, shouldn’t we take the opposite lesson from the first debates, in fact? That you can have a good debate and it doesn’t help you break through because the top of the field is pretty entrenched?

nrakich: We didn’t say he was likely to, though — just that the possibility existed.

He’s already at 130,000 donors, the threshold for the third debate, in large part due to his first debate performance.

natesilver: I guess I’m just saying that I think people are maybe underestimating how much voters like the top-tier candidates when they say they expect a middle-tier candidate to break out.

julia_azari: What we’ve seen so far leaves me questioning whether the top tier is really open to newcomers at this point. I think there’s contention over who will be in that second tier of candidates who meet the requirements for the fall debates, but most of those candidates won’t come close to winning the nomination.

sarahf: Or maybe even making the next debate!

This might be the last time we see many of these candidates on stage because September’s qualifying thresholds will be difficult for them to meet. (Candidates must have at least 2 percent support in four recent qualifying polls1 and 130,000 unique donors.2)

natesilver: There are a lot of middle-tier candidates, so what are the odds that at least one of them will break into the top tier at some point in the race? Maybe fairly high. Let’s say it’s 60 percent, just to make a number up. But that 60 percent is divided between a lot of different candidates.

sarahf: OK, so as to this top-tier vs. middle-tier debate …

Let’s look at night one and unpack some of the dynamics there. As a reminder, night one includes: Sanders, Warren, Buttigieg, O’Rourke, Klobuchar, Williamson, Delaney, Hickenlooper, Ryan, Bullock.

So given the lineup, there’s potential that some of the more moderate candidates — say, Buttigieg, O’Rourke and Klobuchar — maybe try to position themselves against Warren or Sanders, right? And that can maybe help them break through to the top tier? Or at least make the top tier look less fixed?

julia_azari: Yeah, “Can a middle-tier candidate move up?” seems like the unofficial slogan of night one.

sarahf: More so than night two?

julia_azari: I think so. But I reserve the right to flip-flop if one of you convinces me.

nrakich: Agreed, and in fact I’d pay even closer attention to the lower-tier candidates: Hickenlooper, Ryan, Bullock, Delaney. They know that this is their last chance to make a splash before the third debate’s stricter thresholds. And they all have little love for Sanders’s socialism/Warren’s progressivism.

I think they will lash out pretty hard.

julia_azari: And, in fact, I might convince myself to flip-flop because of the timing. If Buttigieg, O’Rourke or Klobuchar has a strong performance (say, on the level of Castro last time) and emerges as the official Biden Alternative for the Heartland Moderate (or whatever, don’t @ me), I think there’s still a strong chance that something else happens on night two that overshadows it.

nrakich: I also think the potential for Sanders-Warren fireworks is overrated. Despite their ideological similarities, they aren’t really competing for the same bloc of voters. Warren supporters are more likely to be higher-income or have a college degree, while Sanders’s support is more working-class.

natesilver: I strongly disagree with Rakich on the Sanders-Warren lanes thing!

sarahf: 🍿

nrakich: 🎆

natesilver: 🍿

sarahf: Finally, the two in-house Nathaniels fighting!

julia_azari: I’m just here for the ratio.

natesilver: But OK, I don’t think looking at the characteristics of Sanders’s current voters is the right way to go about it.

Because he’s lost a shit-ton of support since his last presidential run.

Roughly two-thirds of his supporters from 2016 have gone to other candidates. We know that because he got more than 40 percent of the vote then and is now polling in the mid-teens.

And a lot of those voters probably went to Warren.

Probably some went to Buttigieg, Biden, etc. too.

nrakich: Indeed — according to an Emerson poll conducted earlier this month, 25 percent of Sanders’s 2016 voters still support him, but 20 percent now support Biden, 15 percent support Warren, and 9 percent support Harris.

natesilver: I’m just saying, Sanders has already lost a lot of the voters that he was gonna lose to Warren. Maybe he lost most of them at the start of the cycle and then a few more as she’s gradually gained ground. The voters who are still with Sanders now might be fairly lukewarm on Warren, but that reflects a type of selection bias: They’re the ones who haven’t defected to Warren yet.

nrakich: I take your question, Nate.

And I agree with you generally that Sanders needs to go on the attack more. But that doesn’t necessarily mean he will. Especially when he and Warren are reportedly good friends.

natesilver: Friends, schmends, people are trying to WIN THE PRESIDENCY!!!!

sarahf: And what does that mean for the debate? Does Sanders have an incentive to go hard on Warren?

natesilver: Sanders probably — maybe definitely — needs some of Warren’s current voters to have a shot at the nomination. It doesn’t necessarily mean he needs to go after her, though, which could fairly easily backfire.

His staff, at times, has seemed a little prickly about Warren. Maybe they thought it was Sanders’s turn — he was the second-place finisher last time, after all. But she’s the one who seems to have momentum and whose chances the media is taking more seriously.

But, again, that doesn’t necessarily mean it’s a good look for Sanders to go after her. I’m not sure what he’d even say, exactly.

He has, at times, tried to emphasize his electability vis-a-vis Warren, a strategy that I think is a bit dubious.

nrakich: I feel like that won’t win him a lot of friends among people who already don’t like the way he treated the last woman he faced in a primary.

natesilver: He has sometimes tried to act like he was the OG Democratic Socialist and she’s stepping on his turf, which I don’t think is a particularly compelling message either.

julia_azari: One thing I want to note about Warren and Sanders is how we (media, voters, everyone) understand what goes on within parties in a nomination contest. Because you essentially have two people competing who have somewhat different approaches to their shared ideological lane. So is this competition about candidates and their personalities? Or is it about which approach gets to bear the standard for the economically left wing of the party? It’s kind of remarkable that we’re seeing public contestation at this level — not just between factions but within them.

nrakich: I definitely think it’s a competition of personalities, not ideologies. I think a lot of elites who support Warren really don’t like Sanders because of his “revolution” rhetoric and somewhat ornery personality.

sarahf: What are some other dynamics we expect on night one? Do we think, tactically speaking, it makes sense for the other candidates to position themselves against the front-runners, i.e. Warren and Sanders?

natesilver: I think it makes sense for Klobuchar to push back against them.

nrakich: Yeah, I think it makes a lot of sense for the moderates like Klobuchar, Hickenlooper and Delaney to set themselves up as a foil against Sanders or Warren.

julia_azari: The smart move for Klobuchar-O’Rourke-Buttigieg is to try to emerge as the leader of that pack. I think, if we conceptualize the nomination as a process of coalition-building, there’s potential for Klobuchar to build on her status as a woman, a Midwesterner and a pragmatic candidate. But the staff stuff may have sunk her, I don’t know.

natesilver: Klobuchar might actually have a shot at the nomination. I’m not sure I care what Delaney does though.

nrakich: DeLaNeY sHoUlD bE aT cEnTeR sTaGe

(Nate, did I do that right?)

natesilver: I don’t think you can troll effectively with Delaney.

It’s not like Yang or Williamson, where there’s something inherently trollish about their candidacies.

sarahf: And Steve Bullock, while I don’t think he has a shot at winning the nomination, could still be an interesting addition. At the very least, he wasn’t in the first debate, so voters won’t have heard him make his case yet.

nrakich: Yes, Bullock is a strong candidate on paper: two-term governor of a red state, and he has some institutional support in Iowa. Unlike some of the other lower-tier candidates, you can see a path to the nomination for him, however faintly.

But I would guess that virtually no one has heard words come out of his mouth, so this week will be big for him.

julia_azari: Bullock also has anti-establishment cred from being excluded from the first debate. Will anyone care? I don’t know. As someone writing about party legitimacy, I’m way into watching that unfold.

natesilver: Overall, the moderates would rather be on the stage against Biden, no?

nrakich: Yeah, I think so, Nate, but with Sanders, they’ll still have material to work with.

sarahf: Is the idea here it’s better to be on a stage where you can show what you have in common with someone who’s polling better than you? Rather than showing how you’re different?

julia_azari: Yeah, I think this debate might be a good test of whether it’s good for these kinds of candidates to be on a stage with the front-runner in their “lane” or if it’s better to go up against the front-runner not in their “lane” to establish themselves as the main alternative.

nrakich: I think it’s just because you can make the most effective attack on Biden in person (as Harris showed), and if it lands, you’re likely to be the beneficiary.

natesilver: I think a lot of the moderates need Biden to implode to have a shot, so you’d rather just be on the stage with him so that you can benefit directly from him imploding. It’s harder if you have to count on a parlay of you doing well in one debate and then Biden doing poorly in the other debate but somehow none of the candidates from the other debate get credit for dismantling Biden.

sarahf: OK, on to night two!

Reminder, the stage is: Biden, Harris, Booker, Yang, Castro, Gabbard, Bennet, Inslee, Gillibrand, de Blasio.

nrakich: All of the nonwhite candidates are debating on this night. I find this fascinating.

Also, Biden sharing the stage with them is fascinating.

Harris and Booker in particular have shown that they are eager to attack Biden on racial-justice issues.

sarahf: Right, and we’ve got the potential for a rematch on our hands. What are the non-probabilistic odds, you think, that Harris and Biden spar again?

nrakich: High.

And I think Biden will be readier for it. (Or at least he should be — he has no excuse now.)

natesilver: I think Harris-Biden Round 2 is fairly likely to be the headline that emerges, yeah.

sarahf: My bet is that Booker joins the headline, largely because, as Nathaniel mentioned earlier, he’s also taken Biden to task on issues of race.

Booker also is a pretty strong debater, I think.

natesilver: Could Harris, in theory, rely on Booker to be the more aggressive one and try to remain a bit above the fray?

I’m not saying it’s a good strategy or a bad strategy, but it’s one she could consider.

Biden is still very popular with Democrats and she doesn’t necessarily want to alienate his voters.

julia_azari: I think that’s definitely a possibility and a strategy she could consider. The dilemma with tackling Biden’s record on race is that candidates may want to do it as long as something like reparations isn’t pinned to them when the general election rolls around. Not saying this is right or wrong morally or strategically, but I do think it’s a calculation.

And to some degree, I think that’s sorta the larger dilemma of this primary (I’m really liking the word “dilemma” today, leaning into it) — how does one compete fiercely in this kind of field without alienating the supporters of other candidates?

sarahf: And as we’ve talked about before, if Biden were to falter, both Harris and Booker have some chance of benefiting from supporters switching to them instead. So it will be a fine balance between weakening Biden while not alienating his base too much.

nrakich: FWIW, I think Harris’s attack in the first debate was excellent precisely because it conveyed respect to Biden while also totally destroying him.

sarahf: Yeah, she even started her attack by saying how much she respected Biden.

natesilver: Ohhhh I don’t really think it conveyed much respect.

I mean, it wasn’t out of bounds.

But saying you respect someone as a rhetorical strategy is only loosely correlated with actually conveying respect.

julia_azari: I’m not sure about the respect thing either.

But I think it was a great piece of political theater, and there’s some evidence that debates are good for changing people’s impressions of how viable or electable a candidate is. Harris perhaps helped people envision her on a debate stage with Trump.

nrakich: I have no idea if Harris actually respects Biden, but it’s about how people interpret it, and I think she managed to land a devastating attack in a way that didn’t come off as mean. So I don’t think it alienated anyone but the most diehard Biden fans who think he is above reproach.

Harris’s unfavorable rating went up just 1.4 points after the debate, according to our tracking poll, so few voters seemed put off by her approach.

sarahf: OK, let’s wrap. Top line, what will you be looking for on Tuesday and Wednesday?

nrakich: It’s kind of a boring answer, but I’ll again be looking to see if any of the middle- or lower-tier candidates have a moment that earns them a burst in support. Otherwise, it’s going to be the same old cast of characters on the September stage, and you’ll probably see multiple people drop out. (Note: That may happen anyway.)

natesilver: I’d be interested in if O’Rourke, Buttigieg and/or Klobuchar explicitly play to the center.

Klobuchar seemed reluctant to do that in the first debate.

julia_azari: The four things I’ll be looking for are: 1) movement among top-tier candidates; 2) the porousness of the top tier, i.e. can anyone else get into it; 3) who is competing against whom (e.g. what “lanes” emerge); and 4) what issues emerge as the ones that will define the primary race?

Because how the candidates link themselves to and prioritize issues might give us a sense of how fault lines will emerge as the primary season progresses.

FiveThirtyEight’s most memorable debate moments


  1. National or early-state polls from approved pollsters, released after the first debate and at least two weeks before the third debate on Sept. 12-13.

  2. Including at least 400 individual donors in at least 20 states.

Nate Silver is the founder and editor in chief of FiveThirtyEight.

Nathaniel Rakich is a senior editor and senior elections analyst at FiveThirtyEight.

Sarah Frostenson is FiveThirtyEight’s former politics editor.

Julia Azari is an associate professor of political science at Marquette University. Her research interests include the American presidency, political parties and political rhetoric. She is the author of “Delivering the People’s Message: The Changing Politics of the Presidential Mandate.”