Nate Silver's Blog, page 79

Will The Midterms Decide Who Runs In 2020?

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

sarahf (Sarah Frostenson, politics editor): It is now 21 DAYS UNTIL THE MIDTERMS!! And while voters will mainly be deciding who controls Congress, they’ll also maybe be deciding what kind of Democrat should run in 2020. For instance, if Democrats don’t take back the House, does that mean a Joe Biden run in the 2020 Democratic primary is more likely? Or if there is a blue wave and Democrats gain 60+ seats, does that make the road easier for a more progressive Democrat like Sen. Kamala Harris?

clare.malone (Clare Malone, senior political writer): Man, if the Democrats lose the House, I think there will be some straight-up PANIC.

natesilver (Nate Silver, editor in chief): There would be, although one could ask whether it was warranted or not.

clare.malone: I don’t think Joe Biden needs them to lose the House to prove he’s a good candidate. He could just point to Democratic Senate losses, maybe?

Assuming that Democrats lose in a couple of red states, a candidate like Biden could say, “Look, I will make inroads in a place like that.”

But I’m interested in Nate’s House take.

natesilver: I mean, to a first approximation I think a lot of this stuff is silly.

Here’s why:

There's no clear relationship between midterm losses and what happens in the next presidential election

Sometimes it's 2006 and there are two rough elections in a row
Sometimes it's 2010 and a win comes before a loss
The pattern just isn't strong https://t.co/7dzH6heerv pic.twitter.com/IVwUSew2ix

— David Byler (@databyler) October 15, 2018

As David says, there isn’t much of a pattern for how midterms affect the next presidential election.

Certainly. it will affect Democrats’ attitude, but how much that attitudinal change affects 2020, and whether that is helpful or hurtful to Democrats, is pretty up in the air, IMO.

clare.malone: Right — I mean was just about to say, proof aside (proof! facts!), I think candidates and party apparatchiks always use a loss to motivate their constituents.

That attitudinal thing can be pretty powerful in a primary campaign. See: Bernie Sanders.

natesilver: I’m skeptical that Biden could use Senate losses to justify the need for more conservative candidates … if Democrats also win the House.

We’ll see, though. There are some pretty wacky scenarios that are within the realm of possibility, like Democrats winning 35 House seats but losing four Senate seats.

clare.malone: I think people’s minds are on the Senate right now, though. And the Republican majority there does lie in smaller states and regions that Democrats have gradually lost over the past couple of decades.

It’s not an absurd argument to make in 2019.

perry (Perry Bacon Jr., senior writer): I think Biden has to decide if he wants to run or not. He was kind of confused about whether to run in 2016. And based on what he’s been saying, he doesn’t seem to know now either. I think a really strong push to draft him might encourage him to get in the running. And I think Democrats not winning the House (assuming that they lose the Senate too) will get more people to encourage him to run. Biden would be an important figure if he got in the race, in large part because others in this more “centrist” lane might not run if he is in.

clare.malone: I don’t think Biden is a Mario Cuomo: I think he’ll get in the race. I’m not sure how much he’ll toy with people up until the very end.

natesilver: Are people’s expectations that Democrats will win the Senate? If so, people aren’t paying much attention (certainly not paying much attention to our forecast).

clare.malone: I don’t know. I don’t think people expect that. I guess you hear “blue wave” bandied about and you could make assumptions.

sarahf: And it wasn’t always so dire in the Senate either — it wasn’t until early October that Democrats’ odds worsened dramatically.

But OK, let’s set aside what could happen in the Senate for a moment and assume that there is a huge blue wave in the House and even in some key gubernatorial races like Stacey Abrams’s, in Georgia, and Andrew Gillum’s, in Florida.

It doesn’t mean Democrats win in 2020, but doesn’t it change the playing field of candidates in the Democratic primary? Or would Sens. Harris, Elizabeth Warren and Cory Booker run no matter what?

clare.malone: I think Gillum or Abrams wins would be huge. It would challenge some norms about what sorts of candidates win in states where you need to win over moderates or Republican-leaning independents.

natesilver: Gov. Scott Walker losing his re-election bid in Wisconsin might have some interesting narrative implications too, although not in the same way that Gillum and Abrams do.

perry: I’m interested in Abrams’s and Gillum’s gubernatorial bids and Rep. Beto O’Rourke’s Texas Senate run because they are all making the case that it is a better strategy to try to amp up the base to get greater minority and youth turnout rather than trying to win over swing voters. If they do significantly better in their states than more moderate candidates from previous years, I think that would buttress Democrats like Warren and Harris, who are more likely to run more decidedly liberal campaigns.

But the Midwest is interesting, as Nate is hinting at. The Democrats are doing well in the Midwest with a bunch of candidates who are kind of bland and fairly centrist-friendly. The South and the Midwest are, of course, very different regions, too.

natesilver: I guess I’ve just never dealt with an election before where you’d get the sort of split verdict like the one we’re predicting, where Democrats win the House and do pretty darn well in gubernatorial races but fall short –– and possibly even lose seats –– in the Senate. And some of the high-profile toss-up races could also go in different directions. Maybe Gillum wins in Florida but Abrams loses in Georgia, for example.

In that case, there would be a sort of battle-of-narrative-interpretations over the midterms.

sarahf: As our colleague Geoffrey Skelley wrote, the last time the Senate and House moved in opposite directions during a midterm was in 1982, during under Ronald Reagan’s presidency.

Part of that was because Reagan had a pretty bad approval rating, in the low 40s … which isn’t too far off from where President Trump’s sits now.

natesilver: And I guess 1982 was interpreted as being pretty bad for Reagan? I was 4 years old then, so I don’t remember.

An Upset That Nobody Sees Coming Could Determine Control Of The House

In 2016, one of Hillary Clinton’s mistakes was not campaigning in the wrong states so much as not campaigning in enough states. Of course, it would have been nice if she’d known ahead of time exactly where President Trump was likely to do well — that he really could win in Michigan and Wisconsin, for instance, but not in Virginia and Colorado. But that’s not how polling and election forecasting works in the real world. Polls and forecasts are pretty good instruments, but they’re not all that precise. Nor do they necessarily go wrong in the places you expect them to go wrong. Therefore, campaigns should generally be active in a reasonably broad set of plausibly competitive states and districts. They shouldn’t get too cute by either triaging a race too soon or taking one for granted.

So as you see reports about Republicans or Democrats giving up on campaigning in certain races for the House, you should ask yourself whether they’re about to replicate Clinton’s mistake. The chance the decisive race in the House will come somewhere you’re not expecting is higher than you might think.

Let’s be more specific about that. Below is a table showing House races divided into the seven broad categories we use in our forecast, ranging from “solid D” (at least a 95 percent chance of the Democrat winning) to “solid R” (at least a 95 percent chance of the Republican winning). For each category, I’ve listed the chances that a district within that category will be the tipping-point district, according to FiveThirtyEight’s tipping-point index. The tipping-point index measures the likelihood that a state or congressional district will prove decisive to the overall outcome — in the case of the House, for instance, that it will be the 218th most Democratic or Republican district once all votes are counted on Nov. 6, providing the winning party with at least a 218-217 majority.

The House may be decided in an unexpected place

Projected wins and tipping-point chance by district category, according to the Classic version of FiveThirtyEight’s model as of 5 p.m. on Oct. 15

Tipping-point chance
Projected wins


Category
No. of races
Average race in this category
All races in this category, combined
Dem.
Rep.




Solid D
190
0.02%
3.8%
189.6
0.4


Likely D
16
1.1
16.9
13.7
2.3


Lean D
8
1.8
14.0
5.4
2.6


Toss-up
19
1.4
27.3
9.2
9.8


Lean R
19
1.0
18.5
6.1
12.9


Likely R
48
0.4
17.5
6.7
41.3


Solid R
135
0.015
2.0
0.9
134.1

In considering the battle for the House, it would be easy to concentrate only on the 19 “toss-up” districts (as of Monday evening)1 — plus the eight that are “lean D.” If Democrats win all those districts, plus all the “likely D” and “solid D” districts, they’ll wind up with 233 seats — a net gain of 38 seats from Republicans and comfortably enough to take the House.

It’s extremely unlikely that everything will work out quite so precisely, however. Individual House races are fairly hard to predict. They don’t get all that much polling. Sometimes the candidates make a big difference, and sometimes they don’t. There will be lots of idiosyncratic and even “surprising” demographic patterns that emerge on Nov. 6, but the whole reason they’ll be surprises is because we won’t know about them ahead of time.

What this means is that Democrats will almost invariably lose some of the toss-ups, perhaps along with a couple of the “lean D” races, even if they’re having a pretty good night2 on Nov. 6. Unless we’re really, really lucky, the races just aren’t going to wind up in the exact order our model lists them or in the exact order that the Democratic Congressional Campaign Committee and National Republican Congressional Committee expect.

So it greatly helps Democrats that they also have a long tail of 19 “lean R” seats and 48 “likely R” seats3 where they also have opportunities to make gains. (Conversely, there aren’t that many “lean D” or “likely D” seats that Democrats need to defend.) These races are long shots individually for Democrats — a “likely R” designation means that the Democratic candidate has only between a 5 percent and 25 percent chance of winning in that district, for instance. But they’re not so unlikely collectively: In fact, it’s all but inevitable that a few of those lottery tickets will come through. On an average election night, according to our simulations, Democrats will win about six of the 19 “lean R” seats, about seven of the 48 “likely R” seats — and, for good measure, about one of the 135 “solid R” seats.4 (That is, it’s likely that there will be at least one total and complete surprise on election night — a race that was on nobody’s radar, including ours.)

When I’ve pointed out the importance of the “lean R” and “likely R” races to other election geeks, the general response has been to agree that these seats might be vulnerable, but to suggest that they’ll only fall to Democrats in the event of a landslide, upping the Democrats’ ceiling but not necessarily helping their median projection.

I think this is probably wrong. I don’t want to say “just trust us,” but we spend a lot of time evaluating uncertainty in the forecast, including the crucial issue of the extent to which races are correlated with one another. Indeed, House races are correlated with one another, but not to the same extent that presidential ones are, where the same two candidates are on the ballot in every state. And this year in particular, competitive House races span a pretty wide array of districts that vary in their partisanship, their demographics and whether there’s an incumbent running or not. They also vary in the extent to which they have reliable polling. Thus, the model thinks there’s a 36 percent chance that the tipping-point district — the pivotal race in a close election — winds up coming from the “lean R” or “likely R” pile. Democrats won’t “need” any of those seats if they win all the toss-ups, but it’s highly unlikely that they’ll win all the toss-ups.

To be fair, some of this is just because there are a lot of “lean R” and “likely R” districts. If you took just one “toss-up” district and just one “likely R” district, the “toss-up” would be about four times as likely to produce the tipping-point district. However, there are about three times as many “likely R” districts as “toss-up” districts, which evens things out a lot.

But that long list of “likely R” races is a tangible risk for Republicans. Democrats have raised a ton of money almost everywhere (contra the media narrative, not just in high-profile elections such as the Texas Senate race) and nominated credible candidates all over the map. Where there are districts with demographics that have shifted more than people expect, or complacent incumbents who don’t do a good job of turning their voters out, or last-minute mini-scandals, Democrats are poised to take advantage of those opportunities. That’s a big part of why they’re 6-in-7 favorites in our House forecast.

Politics Podcast: Can Democrats Win Big With Only Women?

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In this week’s episode, the FiveThirtyEight Politics podcast crew considers whether Democrats can win the House or Senate by relying solely on their advantages with women. The team also looks at early indicators of who might run for president in 2020, such as who has visited Iowa, written a book or campaigned for fellow party members.

You can listen to the episode by clicking the “play” button in the audio player above or by downloading it in iTunes , the ESPN App or your favorite podcast platform. If you are new to podcasts, learn how to listen .

The FiveThirtyEight Politics podcast publishes Monday evenings, with occasional special episodes throughout the week. Help new listeners discover the show by leaving us a rating and review on iTunes . Have a comment, question or suggestion for “good polling vs. bad polling”? Get in touch by email, on Twitter or in the comments.

2018-19 NBA Predictions

How this works: These forecasts are based on 50,000 simulations of the rest of the season. Elo ratings — which power the pure Elo forecast — are a measure of team strength based on head-to-head results, margin of victory and quality of opponent. Our CARMELO forecast doesn’t account for wins and losses; it is based entirely on our CARMELO player projections, which estimate each player’s future performance based on the trajectory of other, similar NBA players. Read more »

Design and development by Jay Boice, Rachael Dottle, Ella Koeze and Gus Wezerek. Statistical model by Nate Silver. Additional contributions by Neil Paine. Illustration by Elias Stein.

Why The House And Senate Are Moving In Opposite Directions

At first, I was a little skeptical of the narrative that Justice Brett Kavanaugh’s confirmation process could send the House and Senate moving in opposite directions. Usually in politics, a rising tide lifts all boats — so whichever party benefited from the Supreme Court nominee’s confirmation would expect to see its fortunes improve in both its best states and districts and its worst ones.

But a House-Senate split is exactly what we’re seeing in the FiveThirtyEight forecast. Democratic prospects in the Senate are increasingly dire, having fallen to about 1 in 5. Indeed, it’s been hard to find any good news for Democrats in Senate polling lately. In the House, by contrast, their opportunity is holding up relatively well. In fact, Democrats’ chance of taking the House has ticked back upward to about 4 in 5, having improved slightly from around 3 in 4 immediately after Kavanaugh was confirmed. And while district-by-district House polling has been all over the place lately, Democrats’ position has improved slightly on the generic congressional ballot.

On the surface, you might reason that House and Senate battlegrounds aren’t that different from one another. Yes, the most competitive Senate races this year are in really, really red states. Specifically, the average competitive Senate race, weighted by its likelihood of being the decisive state in determining the majority according to FiveThirtyEight’s tipping-point index, is 16 percentage points more Republican than the country overall.1 But the average competitive House district is also pretty red: 8 points more Republican than the country overall, weighed by its tipping-point probability.

The more time you spend looking at the battlegrounds in each chamber, however, the more you’ll come to two important conclusions:

The House and Senate battlegrounds really aren’t that much alike. In several important respects, in fact, they’re almost opposite from one another. For example, House battlegrounds are more educated than the country overall, while Senate ones are less so.
The Democrats’ map in the House is fairly robust, because they aren’t overly reliant on any one type of district. (This stands in contrast to the Senate, where most of the battlegrounds fit into a certain typology: red and rural). While House battlegrounds are somewhat whiter, more suburban and more educated than the country overall, there are quite a few exceptions — enough so that Democrats could underperform in certain types of districts but still have reasonably good chances to win the House. This differs from Hillary Clinton’s position in the Electoral College in 2016, in which underperformance among just one group of voters in one region — white working-class voters in the Midwest — was enough to cost her the election.

So let’s look in more detail at the characteristics of the House and Senate battlegrounds, starting with some basics: their geographic region (as according to the U.S. Census Bureau) and whether they’re incumbent-held or open-seat races. In the series of charts that follow, I’ll show what these characteristics look like in an unweighted average of all 435 congressional districts, and compare that to what’s happening in battlegrounds. (Rather than handpick the “battleground” contests, I’m weighting all races by their tipping-point probabilities in the House and the Senate; contests more likely to prove decisive have outsized sway in the calculation.)

How House and Senate battlegrounds compare based on incumbency and geography

Chance that a race will have a certain characteristic

Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point states*




Democratic incumbent
40%
6%
46%


Republican incumbent
46
71
29


No incumbent
14
25
25




Characteristic
All congressional districts
House tipping-point districts
Senate tipping-point states




Northeast
18%
19%
2%


Midwest
22
27
32


South
37
27
41


West
23
27
25

*Weighted by tipping-point probability, which is the likelihood that a particular state or district is decisive in determining majority control. Tipping-point determinations are as of 12 p.m. on Oct. 13.

One obvious but overlooked difference between the House and the Senate is that Democratic incumbents have very little exposure in the House but a ton of it in the Senate. For instance, there’s a 46 percent chance that the tipping-point race in the Senate will be one featuring a Democratic incumbent, but only a 6 percent chance for the House. Just the reverse is true for Republicans; they have tons of vulnerable incumbents in the House but few in the Senate. What this means is that, other factors held equal, things that reduce the incumbency advantage will tend to hurt Democrats in the Senate but help them in the House. If, for instance, the Kavanaugh hearings turned the public further against incumbent politicians in both parties, that could contribute to the increasing divergence we’re seeing between the House and Senate forecasts.

Geographically, the competitive House races are almost evenly divided between the four major Census Bureau regions. This is part of what makes Democrats’ map robust: Even if they completely flopped in one of these regions, they could still narrowly win the House by performing to the model’s expectations in the other three. Note, however, that relative to population, the South is slightly underrepresented among the competitive House districts — it represents 37 percent of congressional districts overall but 27 percent of the competitive ones. That’s probably a good thing for Democrats because their coalitions in the South tend to rely on racial minorities and on younger voters — groups that don’t turn out as reliably in midterms as they do in presidential elections.

By contrast, there’s a 41 percent chance that the tipping-point state in the Senate will be in the South. And whereas the Northeast is fairly important to the House map, with a number of competitive races in New York, New Jersey and Pennsylvania, there’s almost nothing interesting happening in the Northeast on the Senate side of the ledger.

Next, here are the political characteristics of competitive districts, based on FiveThirtyEight’s partisan lean index and on whom they voted for in 2012 and 2016. (To make for an apples-to-apples comparison between the House and the Senate, the statistics for Senate races in these next two charts are based on congressional districts within states with competitive Senate races rather than the states overall. For instance, if Tennessee has an 11 percent chance of being the tipping-point state in the Senate, that 11 percent chance is divided between the nine congressional districts in Tennessee to estimate how important individual congressional districts are toward determining Senate control.)

How House and Senate battlegrounds compare based on recent voting patterns

Chance that a race will have a certain characteristic

Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point districts*




Obama-Clinton
39%
15%
27%


Obama-Trump
5
17
4


Romney-Clinton
3
17
2


Romney-Trump
52
51
67




Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point districts*




Very Democratic†
32%

16%


Competitive
29
82
21


Very Republican†
39
18
63

* Weighted by tipping-point probability, which is the likelihood that a particular state or district is decisive in determining majority control. For the Senate, statistics are compiled on a district-by-district basis but weighted based on the probability that the state will be decisive to Senate control. Tipping-point determinations are as of 12 p.m. on Oct. 13.

† At least 10 points more Democratic or Republican than the country overall.

It’s true that House battlegrounds are Republican-leaning — but for the most part, they’re Republican-leaning and not much more than that. Only 18 percent of competitive House races have a partisan lean of R 10 or better for the GOP, for instance. By contrast, weighted by their importance to determining the outcome of the Senate, 63 percent of competitive districts are at least R 10. Romney-Clinton and Obama-Trump districts — that is, districts that split their vote between the past two presidential elections — are quite important in the House but not really a factor in the Senate.

Finally, here’s what competitive districts look like based on three characteristics that are increasingly predictive of voting behavior: race, education and urbanization.

How House and Senate battlegrounds compare based on key demographics and urbanization

Chance that a race will have a certain characteristic

Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point districts*




High education (>=35% bachelor’s degrees)
28%
37%
13%


Medium education
35
41
43


Low education (
37
22
45




Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point districts*





29%
18%
24%


50-80% non-Hispanic white
48
51
38


>80% non-Hispanic white
23
30
38




Characteristic
All congressional districts
House tipping-point districts*
Senate tipping-point districts*




Urban (>2500 people per square mile)
21%
8%
14%


Suburban (500-2500 people per square mile)
23
29
14


Exurban (100-500 people per square mile)
31
39
26


Rural (
25
24
46

*Weighted by tipping-point probability, which is the likelihood that a particular state or district is decisive in determining majority control. For the Senate, statistics are compiled on a district-by-district basis but weighted based on the probability that the state will be decisive to Senate control. Tipping-point determinations are as of 12 p.m. on Oct. 13.

I’ve defined high-education districts as those where at least 35 percent of the adult population has a bachelor’s degree. By that measure, 28 percent of congressional districts in the country overall are highly-educated. But 37 percent of the House battleground districts are highly-educated. By contrast, only 13 percent of the districts that are most important to Senate control have high education levels.

Racially, both House and Senate battlegrounds are whiter than the country as a whole, but the skew is worse in the Senate: 38 percent of districts most important to Senate control are at least 80 percent non-Hispanic white, compared to just 23 percent of districts in the country overall.

Lastly, competitive House districts are concentrated in the suburbs and exurbs (defined based on population density), which make up about half of congressional districts overall but closer to two-thirds of competitive ones in the House. Suburban and exurban districts are quite unimportant to the Senate, however, where the key races are disproportionately based on rural states or in states such as Nevada with a mix of urban and rural areas with little in between.

I’m not going to go on for too much longer because I hope those numbers really speak for themselves. I suppose I had some intuition about how different House and Senate battlegrounds are different from one another — but that intuition didn’t match how sharp the differences are in the data.

Politics Podcast: Two Forecasts Diverged In A Wood

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In this installment of “Model Talk” on the FiveThirtyEight Politics podcast, Nate Silver explores different hypotheses for why the House and Senate forecasts have moved in opposite directions in recent days. He also discusses the different types of uncertainty at play in the election and takes questions from listeners.

You can listen to the episode by clicking the “play” button in the audio player above or by downloading it in iTunes , the ESPN App or your favorite podcast platform. If you are new to podcasts, learn how to listen .

The FiveThirtyEight Politics podcast publishes Monday evenings, with occasional special episodes throughout the week. Help new listeners discover the show by leaving us a rating and review on iTunes . Have a comment, question or suggestion for “good polling vs. bad polling”? Get in touch by email, on Twitter or in the comments.

Politics Podcast: Are Any Of The Post-Kavanaugh Narratives Right?

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In a live taping of the FiveThirtyEight Politics podcast, the crew reviews the narratives that have emerged from Justice Brett Kavanaugh’s confirmation process and debates which ones are correct. They also discuss over- and underrated Senate races and play a round of the game “Guess What Americans Think.”

You can listen to the episode by clicking the “play” button in the audio player above or by downloading it in iTunes , the ESPN App or your favorite podcast platform. If you are new to podcasts, learn how to listen .

The FiveThirtyEight Politics podcast publishes Monday evenings, with occasional special episodes throughout the week. Help new listeners discover the show by leaving us a rating and review on iTunes . Have a comment, question or suggestion for “good polling vs. bad polling”? Get in touch by email, on Twitter or in the comments.

What’s Behind Democrats’ Shrinking Senate Odds?

Republicans’ chances of keeping the Senate are up to about a 4 in 5 (79 percent), according to the “Classic” version of the FiveThirtyEight forecast. Republicans have always been favored to hold the Senate, but that’s nevertheless a meaningful improvement from recent weeks, when their odds were generally hovering between 2 in 3 (67 percent) and 7 in 10 (70 percent) instead.

This means Republicans have left what you might call the “Hillary Clinton zone” — the name I mentally assign to 70-ish percent chances where you’re only a normal-sized polling error away from losing the election. Less snarkily, Republicans have escaped a situation where Democrats could win the Senate merely by winning all the toss-up races. Instead, Democrats would have to win at least one of the four races — North Dakota, Tennessee, Texas and the Mississippi special election — that our model currently rates as “lean Republican” or “likely Republican.”1 to have a mathematical shot at the Senate. So, while it’s crucial to remember that a 4 in 5 chance is a long way from 100 percent, the GOP is in a pretty good position.

Rather than get too philosophical, however, let’s pose a more specific question: Is the GOP’s improved position in the Senate because of just one or two races? Or a certain type of race? (For instance, races in red states?) Or is it more broad-based?

Here’s a comparison of the odds our model is showing for each competitive2 Senate race as of now (Oct. 9), compared with where they stood on Sept. 12. Why Sept. 12? For one thing, that was the day we launched our Senate forecast. But it was also a relatively calm moment in the news cycle. There had been just enough time for some post-Labor Day polls (traditionally a time when voters become more attentive to campaigns) to filter into our polling averages. Brett Kavanaugh’s initial confirmation hearings had taken place, but Christine Blasey Ford had not yet had her name published by The Washington Post.

How Democrats’ odds have changed in Senate races

Democratic chances of winning on Sept. 12 vs. Oct. 9 (as of 10 a.m.), according to the FiveThirtyEight 2018 Senate forecast

Lite forecast (polls only)
Classic forecast (polls plus fundamentals)


State
9/12
10/9
Change
9/12
10/9
Change




North Dakota
40%
14%
-26
62%
31%
-31


Tennessee
55
41
-14
31
29
-2


Missouri
59
51
-8
69
57
-12


Indiana
75
68
-7
84
75
-9


Texas
27
23
-4
31
25
-6


Nevada
55
52
-3
59
50
-9


Minnesota special
87
85
-2
91
89
-2


Mississippi special
25
23
-2
16
14
-2


Montana
78
79
1
90
84
-6


Wisconsin
93
96
3
95
97
2


West Virginia
85
88
3
87
88
1


Florida
50
57
7
57
60
3


Arizona
61
68
7
64
65
1


Ohio
88
97
9
91
95
4


New Jersey
78
88
10
93
92
-1


Overall Senate
28
21
-7
32
21
-11

Races in which Democrats’ chances have consistently been greater than 95 percent or less than 5 percent in the Classic version of the forecast are not listed.

As you can see in the table, I’ve shown how the numbers have changed in both the Lite version of our forecast, which sticks to the polls as much as possible, as well as in the Classic version, which incorporates “fundamentals” (non-polling factors such as fundraising and historical trends that help predict the outcome).3 For some races, these tell different stories. In Tennessee, for instance, the Lite forecast shows Democrat Phil Bredesen’s chances waning, reflecting that Republican Marsha Blackburn has gained in polls. But the Classic version of our Tennessee forecast is essentially unchanged since last month because the shift toward Blackburn was expected based on the fundamentals since Tennessee is a very red state.

In the Lite version of our model, Democrats’ decline really boils down to a few states: Indiana, Missouri, Tennessee and especially North Dakota, where Democratic incumbent Heidi Heitkamp went from slightly behind in polls to way, way behind. Note that these are all very red states and that three of the four feature Democratic incumbents. (And Bredesen, as a former governor, might be thought of as a quasi-incumbent.)

Outside of these states, Democrats’ numbers have held up pretty well. In fact, they’ve improved in several more purplish states such as Ohio, Florida and Arizona. Furthermore, somewhat contrary to the conventional wisdom, Bob Menendez, the embattled Democratic incumbent in New Jersey, has seen his numbers improve in the polls, not worsen.

To summarize, the pattern in Senate polls has been as follows:

In general, Democrats’ position has gotten worse in red states but has been steady-to-improving in purple and blue states. There are a couple of exceptions to this pattern (Joe Manchin has continued to poll well in West Virginia) but not many.
On top of that, Democrats have had particular problems in North Dakota, where Heitkamp has seen her numbers go especially south. In fact, absent Heitkamp’s decline, Democrats’ overall position in the Lite forecast is about the same as it was a month ago. (The declines in states such as Indiana are offset by gains in states such as Florida.) Since North Dakota is rarely polled, that raises the question of whether Heitkamp’s position was this bad all along and didn’t have much to do with her decision to vote against Kavanaugh’s confirmation to the Supreme Court; notably, one of the polls showing her down double digits was conducted almost entirely before the hearing with Ford and Kavanaugh on Sept. 27.

The Classic version of our model adds more complexity to the story. Although the polls have moved in the direction the fundamentals predicted in some states, such as Florida, New Jersey and Tennessee, it’s having trouble with Democratic incumbents such as Heitkamp and Missouri’s Claire McCaskill in very red states. The basic heuristic behind the Classic version of our model is that it’s very rare for a party’s incumbents to lose when national trends favor it. So the Classic model has been expecting these Democratic incumbents to gain ground in the polls. Instead, with the exception of Manchin and arguably Montana’s Jon Tester, the Democratic incumbents have been losing ground.

Overall, this is one of those times where the “what” is easier than the “why.” The what is that Democrats’ position has worsened in the Senate as a result of declining numbers in deeply red states — where, because of their terrible Senate map, Democrats have a ton of exposure. But the why is not totally clear: It might be attributable to Kavanaugh, or it might have been baked in all along.

Politics Podcast: Collins Says ‘Yes’ On Kavanaugh

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After Republican Sen. Susan Collins of Maine said Friday that she would vote for President Trump’s nominee to the Supreme Court, Brett Kavanaugh’s confirmation was all but assured. In this emergency episode of the FiveThirtyEight Politics podcast, the team discusses the upcoming Senate vote and its implications for the midterm elections.

You can listen to the episode by clicking the “play” button in the audio player above or by downloading it in iTunes , the ESPN App or your favorite podcast platform. If you are new to podcasts, learn how to listen .

The FiveThirtyEight Politics podcast publishes Monday evenings, with occasional special episodes throughout the week. Help new listeners discover the show by leaving us a rating and review on iTunes . Have a comment, question or suggestion for “good polling vs. bad polling”? Get in touch by email, on Twitter or in the comments.

Politics Podcast: Collins Says Yes On Kavanaugh

By Nate Silver, Geoffrey Skelley, Micah Cohen and Sarah Frostenson, Nate Silver, Geoffrey Skelley, Micah Cohen and Sarah Frostenson, Nate Silver, Geoffrey Skelley, Micah Cohen and Sarah Frostenson and Nate Silver, Geoffrey Skelley, Micah Cohen and Sarah Frostenson












 












More: Apple Podcasts |
ESPN App |
RSS
| Embed


Embed Code

After Sen. Susan Collins said she would vote for Brett Kavanaugh Friday, his confirmation to the Supreme Court was all but assured. In this emergency episode of FiveThirtyEight’s Politics podcast, our politics team discusses the confirmation vote and its implications for the midterm elections.

You can listen to the episode by clicking the “play” button in the audio player above or by downloading it in iTunes , the ESPN App or your favorite podcast platform. If you are new to podcasts, learn how to listen .

The FiveThirtyEight Politics podcast publishes Monday evenings, with occasional special episodes throughout the week. Help new listeners discover the show by leaving us a rating and review on iTunes . Have a comment, question or suggestion for “good polling vs. bad polling”? Get in touch by email, on Twitter or in the comments.