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

sarahf (Sarah Frostenson, politics editor): Tonight marks the fourth Democratic primary debate, and although we’ve written, as a site, that maybe the race is now just between two or three candidates … there are actually 12 candidates on the debate stage. Which kind of begs the question: How much do these debates actually matter? Are they winnowing the field? Helping voters better understand the candidates?

In honor of one of my favorite debate-style questions that seems to have fallen out of favor, a quick show of hands 👋 — who thinks these debates matter?

galen (Galen Druke, podcast producer and reporter): I think debates can matter in primaries. But I don’t think the debates in the 2020 Democratic primary have mattered very much.

So … timid hand raise from me.

julia_azari (Julia Azari, political science professor at Marquette University and FiveThirtyEight contributor): 👋I think they have mattered.

perry (Perry Bacon Jr., senior writer): The DNC has used the debate qualification process to basically winnow the field — that has mattered, of course. But I don’t think the actual debates have mattered much.

galen: I don’t even think the DNC’s criteria to determine who makes the debates have mattered all that much!

The public doesn’t seem particularly interested in anyone beyond the top 3-5 candidates.

sarahf: Galen bringing the heat 🔥

julia_azari: Here’s why I’d argue the debates have mattered: 1) This field has more potential front-runners than any in recent history, with maybe the exception of the Republican field in 2016. 2) Debates offer an opportunity for front-runners to show their flaws.

It’s notable, for instance, that Elizabeth Warren has managed to get through the debates without having any bad moments so far. And with Joe Biden, his debate performances haven’t been outstanding necessarily, but his support hasn’t changed a ton either.

perry: Julia, are you saying the debates haven’t been bad for Biden?

julia_azari: Right, I don’t think they have been. Sure, the debates have showcased his flaws in a way that wouldn’t be as evident without them. (He’s slow on his feet, at times, and rambles). But the debates have also reinforced conceptions that folks had of Biden going in; namely, that he’s moderate and looking to carry on former President Barack Obama’s legacy. Entrenching the status quo still has an effect; it’s just hard to make a big show of it.

sarahf: And what about someone like Kamala Harris? Can’t we trace her highs — and lows — to the debates?

julia_azari: Harris definitely has had a series of bad debate moments, and they have mattered. She’s had lines that landed poorly in the third debate, flailed a bit on health care questions in the second debate and later faced backlash against her confrontation with Biden in the first debate.

galen: But isn’t it also true that Harris’s story is more of a reversion to the mean after her boost from the first debate wore off?

After all, she had lost roughly a third of what she’d gained in the polls by the second debate, and her fall in the polls wasn’t about debate performance.

sarahf: But her rise was!

galen: OK, sure. The debate mattered … for two weeks.

Which a nominee does not make.

sarahf: Haha, what about someone like Warren, though? Isn’t there an argument that her debate performance has helped fuel some of her rise in the polls? As Julia mentioned earlier, it is notable that she hasn’t really had a bad debate performance yet.

galen: So, I looked at this a bit before our chat, and it is clear that Warren began rising in the polls before the first debate on June 26 and 27.

And sure, you can see some upward movement in the polls in the week or so after the second and third debates. But it’s hard to chalk that up to just her debate performance because she’s been gaining steadily throughout the summer. In fact, some of her biggest gains came in the last two weeks, which was long after the third debate on Sept. 12.

perry: As Galen said, Warren has been steadily rising in the polls for months now — but I’d argue that none of the debates were big inflection points for Warren or the other candidates, for three reasons: 1) Biden entered the race with strong numbers, and he’s largely maintained his standing. 2) Sanders’s numbers have fallen, but that doesn’t seem to be tied to the debates; and 3) None of the lower-profile candidates have broken out in the debates. Pete Buttigieg’s rise, for example, happened outside of the debates.

galen: Amen to what Perry said.

The Warren story is about running a good campaign and the media loving her.

It’s not a story of owning the debates.

julia_azari: I would never argue that Warren’s story was mainly about owning the debates. But I don’t think we can entirely dismiss them either. Think of debates like vice-presidential picks: They can do a fair amount of harm, but they also rarely help.

True, this argument is more applicable to the front-runners than the other candidates — but debates are important for highlighting a candidate’s flaws.

perry: If Julia’s argument is ‘debates matter because Biden and Warren could have screwed up really bad and didn’t,’ I agree with that.

I don’t think Harris’s decline is because of the debates, but we might just disagree there.

sarahf: OK, so it sounds as if debates serve two main functions: 1) Test out the strength of the front-runners; 2) Give someone who isn’t a front-runner an opportunity to break through.

We’ve talked about the first point quite a bit, but perhaps the second point really hasn’t been borne out this cycle? Because even after Julián Castro had a stand-out performance in the first debate, or Beto O’Rourke performed well in the third debate, their numbers in the national polls haven’t shifted that much.

julia_azari: Yeah. I mean, there were brief moments where it looked like someone’s performance might shift the race, but that just hasn’t happened. And I’d argue some of the minor, yet plausible, candidates — Amy Klobuchar, O’Rourke — just haven’t had great performances, overall.

perry: Is a debate performance only good or bad if it moves the numbers, though?

Serious question.

sarahf: This feels like the old “if a tree falls in the forest” question … but yes, right??

julia_azari: I think you can talk about someone’s debate performance separate from his or her polling numbers.

Take Biden in the last debate. He got flustered when asked a question about the legacy of segregation in the U.S., and his response was a word salad in which he suggested playing a record player at night could help children be exposed to more words. It was, as Jamil Smith at Rolling Stone pointed out, a really troubling answer that underscored just how out of touch Biden is on issues of race.

But as we discussed earlier, Biden’s numbers haven’t really shifted because of the debates. Instead, I think his debate performances have staked out where he falls in a party that is increasingly split on the question of whether the party is too “woke” on issues of race, as well as whether returning to the status quo before Trump is desirable.

perry: So I agree with this, and I think the debates have shaped the contours of how the race is being discussed.

Biden’s weird comment about record players, for instance, has opened the door for people who were already against him to strengthen their case to people who might be inclined to like Biden (black voters.)

I’m increasingly convinced that I should be watching the debate for the discussions of issues, not for how the event affects the polls. So when I say the debates don’t matter, I mean in that they don’t matter in terms of affecting the horse race. I definitely think the debates matter for better understanding the divides in the party.

galen: I’ve definitely learned about the contours of the Democratic Party from watching these debates. The first debate, in particular, was interesting for showing how far to the left the candidates thought they had to go in order to win. But also …

THIS ISN’T HORSESHOES AND HAND GRENADES, PERRY!

WINNING IS WHAT MATTERS.

perry: Well, winning matters, sure. But Biden has now called “Medicare for All” too radical in several debates. That is not great for Warren if she is the nominee — since Trump and his team can quote Biden criticizing that policy.

However, the fact that the debates have all led with a discussion around health care has definitely helped frame the primary around this issue, turning the larger “electability” discussion into a policy divide (Medicare for All vs. “Medicare for everyone who wants it.”)

julia_azari: And, of course, once you’ve won the nomination, it matters what you do with your coalition. Can you keep it together? Are people disgusted with you? There’s now a whole other thing to win — the general election.

galen: I like that point, Julia, but I also think that how the eventual nominee is defined will have a lot more to do with how Republicans characterize them through campaigning than with what Democrats said about them during the debate.

julia_azari: But the debates do reveal candidates’ positions and force candidates to occasionally take firm stances.

perry: So what have the debates revealed thus far?

sarahf: That aside from Biden, no other moderate candidate has really caught on?

I continue to be amazed that no other moderate candidate has really emerged as an alternative to Biden (maybe Buttigieg).

julia_azari: Well, the revelations are limited to a degree, given the party is changing, but I’d say they include: Biden will stick to his positions on race from the early 1990s, Castro is well-versed on LGBT issues, and Beto wants to take away your AR-15.

perry: I do think the second and third debates — and the fallout from them — revealed a party that wants to move on from many of Obama’s policies, but at the same time, can’t really abide by any direct criticism of Obama.

galen: What about positions that will shape the 2020 general election?

I think, for instance, Warren’s announcement that she supports decriminalizing crossing the border — and the fact that she raised her hand in the first debate when asked if she supported it — is a 2020 attack ad if she wins the nomination. Support for decriminalizing border crossing among Democrats is also unclear. Some pollsters like NPR/PBS News Hour/Marist have found middling support (45 percent), although other progressive pollsters like YouGov Blue have found that Democrats are perhaps warming to the idea.

perry: I mean, I think Democrats will support this position and basically all of Warren’s positions if she is the nominee, although I know decriminalizing border crossings is a controversial stance.

galen: Oh, I don’t think Democrats won’t vote for Warren or support her positions, but can Democrats win a general election with only support from “get in line with the party” Democrats? Maybe. I don’t know.

perry: I tend to think that the argument that “Democrats’ liberal positions in the primary will hurt them in the general” should be tempered. After all, Trump ran a primary campaign that advocated barring all Muslims from entering the U.S. and building a border wall between the U.S. and Mexico. He didn’t back down in the general, and now he’s president.

julia_azari: Right, perhaps one of the more lasting messages of 2016 is you don’t have to run to the center to win.

sarahf: OK, to wrap — it seems as if there is some consensus that the debates have mattered, at least in helping us better understand where the party stands on certain issues or what direction the party could move in. And maybe the debates have accomplished more of that — at least this cycle — than they have impacted individual candidates?

galen: Here’s a take we can all agree on (maybe): The debates have mattered for political science, though perhaps not for the actual primary race.

Actually, I have a caveat to make.

There are going to be SO MANY more debates.

And they could still change things, especially as the field winnows.

sarahf: Wow, backtracking.

galen: Haha, this isn’t a backtrack. I’ve maintained that the debates haven’t mattered so far.

julia_azari: I think we’re feeling some of what we’re feeling because people aren’t paying attention yet. For people who follow politics closely enough to watch the early debates, much of what we saw confirms previous stereotypes about who the candidates are.

galen: 🙌

Julia speaking truth.

perry: My concluding thought is that I keep thinking the debates will change the poll numbers, and they just aren’t. And that’s made me rethink some of my assumptions about politics, television and the Democratic Party.